JP2012138219A - Sample stage device, and electron beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a specimen to a desired position in a desired attitude by a simple and intuitive operation.SOLUTION: When a multi-axial stage 40 of a scanning electron microscope 10 is rotated horizontally, inclined or moved horizontally, an operation of rotating, inclining or horizontally moving an image for specification is performed by means of a mouse 62 while creating an image for specification from an SEM image obtained from a signal of a secondary electron detector 20 and displaying the image on an image display unit 61. A coordinate generation means 52 converts the current coordinates of the multi-axial stage 40 based on the image for specification after operation, and multi-axial stage drive control means 53 drives the multi-axial stage 40 by the converted coordinates.

Description

  The present invention relates to a sample stage apparatus and an electron beam apparatus, and more particularly, a sample stage apparatus having a plurality of degrees of freedom including plane rotation and holding a sample in a predetermined posture and position based on designated coordinates, and the sample stage apparatus To an electron beam apparatus.

  As an electron beam apparatus as described above, there is a scanning electron microscope provided with a multi-axis stage having five degrees of freedom (see Patent Document 1). As shown in FIG. 8, this multi-axis stage is capable of moving the sample 220 in five degrees of freedom: front-rear and left-right directions (X, Y), up-down direction (Z), plane rotation (R), and tilt (T). It has a mechanism that can. According to the scanning electron beam apparatus including such a multi-axis stage, the sample can be observed in an arbitrary posture and position.

JP 2002-319364 A

  However, the scanning electron microscope as described above has a problem that it takes time and labor to observe the sample when the sample to be observed is rotated to observe the same observation region from another direction.

  FIG. 9 is a schematic diagram for explaining an observation state in a conventional scanning electron microscope. As shown in FIG. 9A, when the tilt observation image 210 from the A direction of the sample is obtained, the upper surface 211 and one side surface 212 of the sample can be observed. When it is desired to observe the other side surface 213 of the sample from such a state, it is necessary to rotate the sample and change the inclination to perform observation from the B direction shown in FIG. By performing observation from this direction, as shown in FIG. 9B, the upper surface 211 and the other side surface 213 can be displayed and observed on the observation image 210 of the sample.

  However, when observing the same observation area of the sample from different directions in this way, in conventional scanning electron microscopes, the user observes the sample and moves the multi-axis stage little by little to the extent that the sample is not lost. It is necessary to move the sample by driving in the directions (X, Y), the rotation direction (R), and the tilt direction (T). Since the observation position of the sample is generally deviated from the rotation center and tilt axis of the multi-axis stage, the same region cannot be observed unless the position is adjusted in the front-rear and left-right directions as the multi-axis stage rotates and tilts. Such an operation is particularly troublesome when observation is performed at a high magnification or when a sample to be observed is large.

  Accordingly, an object of the present invention is to provide a sample stage device and an electron beam device that can move a sample to a desired posture and position by a simple and intuitive operation.

  The invention according to claim 1 for solving the above-described problem has a multi-axis stage having a plurality of degrees of freedom including plane rotation and holding a sample in a predetermined posture and position based on a designated posture and position coordinates. A designation image generating means for generating a designation image for displaying a photographed image of the sample in a desired posture and position based on the observation image of the sample obtained in the initial state, and a display device for displaying the designation image And a posture position designation means having a pointing device for designating the posture and position of the sample on the operation image of the display device, and the setting coordinates of the multi-axis stage based on the designation image designated by the posture position designation means And a multi-axis stage drive control means for driving and controlling the multi-axis stage based on the set coordinates.

  Similarly, the invention of claim 2 is the sample stage apparatus according to claim 1, wherein the observation image of the sample in the initial state is obtained based on charged particles emitted from the sample irradiated with the electron beam. It is characterized by that.

  Similarly, the invention according to claim 3 is the sample stage apparatus according to claim 1, wherein the observation image of the sample in the initial state is an optical image of the sample.

  Similarly, the invention of claim 4 is the sample stage device according to any one of claims 1 to 3, further comprising coordinate storage means for storing one or more sets of coordinates specified by the target specifying means, The axis stage drive control means drives the multi-axis stage based on the coordinates stored in the coordinate storage means.

  Similarly, the invention according to claim 5 is the sample stage device according to any one of claims 1 to 4, wherein the multi-axis stage is 5 of tilt, Y direction, X direction, Z direction, and horizontal rotation. It is characterized by having three degrees of freedom.

  Similarly, the invention of claim 6 is an irradiation means for scanning the sample with an electron beam, a sample information generation means for generating sample information based on charged particles from the sample irradiated with the electron beam, and claims 1 to An electron beam apparatus comprising: the sample stage apparatus according to any one of Items 5 above.

  Similarly, the invention of claim 7 is characterized in that the electron beam apparatus according to claim 6 is a scanning electron microscope.

  Similarly, the invention of claim 8 is characterized in that the electron beam apparatus of claim 7 comprises an optical microscope.

  Similarly, the invention of claim 9 is the electron beam apparatus according to any one of claims 6 to 8, wherein a plurality of coordinates are stored in a plurality of coordinates specified by a designated designation image and the plurality of coordinates. Image storage means for storing a plurality of observation images of the sample at each posture and position of the sample stage device set based on the above, and a continuous display means for continuously displaying the plurality of stored observation images. Features.

  According to the present invention, the multi-axis stage can be set to a predetermined posture and position simply by setting the observation posture and position of the sample while visually recognizing the operation image of the sample. The sample can be set to the posture and position of and can be observed.

It is a schematic diagram which shows schematic structure of the scanning electron microscope which concerns on the example of embodiment. It is a block diagram which similarly shows the control system of a scanning electron microscope. It is a schematic diagram which similarly shows the production | generation and imaging state of the designation | designated image of a scanning electron microscope. It is a schematic diagram which similarly shows the image for designation | designated of a scanning electron microscope. It is a flowchart which similarly shows the procedure of observation of a scanning electron microscope. It is a flowchart which similarly shows the setting procedure of the sample attitude | position and position of a scanning electron microscope. It is a flowchart which similarly shows the image display procedure of a scanning electron microscope. It is a schematic diagram which shows the movement freedom degree of a sample. It is a schematic diagram for demonstrating the observation state in the conventional scanning electron microscope.

  A scanning electron microscope according to an embodiment for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a schematic configuration of a scanning electron microscope according to an embodiment. The scanning electron microscope 10 includes an optical microscope 30 in the same housing, and acquires and displays SEM image data and optical image data of an observation region in the sample 18. First, the basic configuration of the scanning electron microscope 10 will be described.

  The scanning electron microscope 10 converges the electron beam 13 generated from the electron beam source 12 in the upper part of the lens barrel 11 with the condenser lens 14, deflects it with the deflection coil 15, and adjusts the convergence and focus with the objective lens 16, The sample 18 in the sample chamber 17 is scanned. The sample 18 is disposed on the multi-axis stage 40. The multi-axis stage 40 includes a known drive mechanism such as a motor or a screw mechanism, and the sample 18 is set to have the axis in the front-rear and left-right directions (X, Y), the vertical direction (Z), the horizontal rotation (R), and the X-axis direction. The sample can be moved with five degrees of freedom of tilt (T) (see FIG. 8), and the sample can be moved to a specified position and rotated horizontally, and can be tilted at an arbitrary angle. In the multi-axis stage 40, an inclination mechanism 41, a Y-direction movement mechanism 42, an X-direction movement mechanism 43, a Z-direction movement mechanism 44, and a rotation mechanism 45 are arranged from the lower stage. The multi-axis stage 40 is driven and controlled by a control unit 50 (see FIG. 2) described later.

  The charged particles 19 such as secondary electrons and reflected electrons generated from the sample 18 are detected by the secondary electron detector 20 and synchronized with the scanning state of the electron beam 13 by the SEM image display control means 55 (see FIG. 2). The SEM image data is obtained by processing, and the SEM image is displayed on the image display device 61 (see FIG. 2).

  The optical microscope 30 includes an optical system in an optical barrel, and also includes a light source that illuminates the sample 18, an electronic image sensor such as a CCD image sensor, and a CMOS element, and outputs optical image data. Then, an enlarged optical image of the observation region of the sample 18 is displayed on the image display device 61 (see FIG. 2). Here, the optical axis of the optical microscope 30 is inclined at a predetermined angle so as to intersect the optical axis of the scanning electron microscope 10 in the observation region of the sample 18. The optical microscope 30 may be disposed so as to coincide with the optical axis of the scanning electron microscope. In this embodiment, there is no adverse effect on the observation conditions of each other. For example, if a through-hole is formed in the optical system of an optical microscope in order to pass an electron beam, adverse effects such as partial darkening of the optical image of the optical microscope may occur, but this embodiment eliminates such an effect. can do.

  Here, the imaging magnification of the scanning electron microscope 10 and the optical microscope 30 can be appropriately changed according to the purpose of imaging. When determining the imaging position of the sample 18, it is preferable to set the imaging magnification of the optical microscope 30 to be smaller than the imaging magnification of the scanning electron microscope 10. In addition, the sample 18 can be observed by being tilted at an arbitrary angle. When the sample surface is tilted in a direction perpendicular to the optical axis of the optical microscope 30, a good optical image can be obtained by the optical microscope 30.

  Next, control of the scanning electron microscope according to the present embodiment will be described. FIG. 2 is a block diagram showing a control system of the scanning electron microscope according to the embodiment. Connected to the scanning electron microscope 10 is a control unit 50 that performs display control of the image of the scanning electron microscope 10 and drive control of the multi-axis stage 40. The controller 50 is connected to posture position specifying means 60 for an operator to specify the posture and position of the multi-axis stage 40. The posture position designation means 60 includes an image display device 61 that displays a captured image and a designated image for posture and position designation, and a mouse that is a pointing device in which an operator designates a point on the image display device 61 and designates processing. 62 and a keyboard 63 for inputting text and numerical values. As the pointing device, for example, a trackball other than the mouse can be used. Also not. For text and numerical input devices, means other than the keyboard can be used.

  The control unit 50 includes a designation image generation unit 51 that generates a designation image to be displayed on the image display device 61, and a coordinate generation unit 52 that generates coordinate data for driving the multi-axis stage 40 based on the designation image. A multi-axis stage drive control means 53 for driving and controlling the multi-axis stage 40 based on the coordinate data, a coordinate memory 54 for storing a plurality of coordinate data, and an image based on a signal from the secondary electron detector 20. An SEM image display control means 55 for displaying an SEM image on the display device 61, an designation image memory 56 for storing designation image data generated by the designation image generation means 51, and an imaging for storing a plurality of captured images. And an image memory 57.

  The designation image generation means 51 generates a designation image based on the SEM image acquired in the initial state and stores it in the designation image memory 56. While observing the designation image displayed on the image display device 61, the operator designates this image with the mouse 62 and horizontally rotates (R), tilts (T) so that the sample has a desired posture and position. ), Plane position (X, Y), and magnification state. Based on this designation, the designation image generation means 51 displays the designation image stored in the captured image memory 57 in a designated state by rotating, tilting, moving the plane, and scaling the designation image. Convert.

  FIG. 3 is a schematic diagram showing the generation and imaging state of the designated image of the scanning electron microscope according to the embodiment, and FIG. 4 is a schematic diagram showing the designated image of the scanning electron microscope. The designation image generation means 51 first generates the designation image 110 based on the initial SEM image. In this example, the designation image 110 is an image taken from the A direction with the sample tilted. In addition, this designation image can be made schematic by omitting details in addition to using the SEM image as it is. The designation image 110 is stored in the designation image memory 56. In this example, in the designation image 110, the upper surface 111 and the one side surface 112 on the near side appear, and the other side surface 113 on the far side is not displayed. This designation image 110 is used for designation and serves as a standard indicating a desired posture position state.

  The designation image generation means 51 deforms the designation image 110 stored in the designation image memory 56 according to the designation from the posture position designation means 60. In this embodiment, the processes that can be specified with the mouse 62 are horizontal rotation movement, tilt movement, plane movement, and magnification change. The sample is rotated by rotating the wheel of the mouse 62, the sample is tilted by dragging the mouse with the right mouse, the plane is moved by the left drag of the mouse, and the magnification is changed by rotating the wheel while being pressed.

  For example, when the sample is observed from the direction of arrow A (FIG. 3A), when the sample is observed from the direction of arrow B, that is, when the sample is rotated 180 ° (FIG. 3B), the operator moves the mouse 62. Rotate the wheel. Along with this, the designation image generation means 51 rotates the designation image 110, and the operator observes this image (FIG. 3C) to obtain a desired state. Here, since the designation image generation means 51 is a rotation of the designation image 110 stored in the designation image memory 56, the designation image 110 (FIG. 3C) to be displayed is actually displayed. Unlike the image observed in FIG. 1, the one side surface 112 remains appearing and the other side surface 113 is not displayed. It should be noted that the designation image 110 can be generated by the SEM image display control means 55 by inputting values of movement and magnification change from the keyboard 63.

  In this example, the coordinate generation means 52 generates each coordinate of the multi-axis stage 40 based on the display state of the designation image 110 and stores it in the coordinate memory 54, and the multi-axis stage drive control means 53 based on the coordinates. The multi-axis stage 40 is driven.

  In a state where the multi-axis stage 40 is driven based on the designated coordinates, an SEM image is generated by the SEM image display control means 55 based on a signal from the secondary electron detector 20 and displayed on the image display device 61. (FIG. 3D). In this observation image 120, the upper surface 121 and the side surface 123 which is the back side before rotation are displayed on the front side, and a desired observation image after rotation can be obtained.

  The designation image generation means 51 also changes the designation image 110 and displays it on the image display device 61 when rotating, tilting, moving the position, and changing the magnification. FIG. 4 is a schematic diagram showing a designation image of the scanning electron microscope. 4A shows the designation image 110 at the time of rotational movement, FIG. 4B shows the designation image 110 at the time of tilt movement, and FIG. 4C shows the designation image 110 at the time of horizontal position movement and magnification change. ing.

  Specifically, during the rotation of the sample shown in FIG. 4A, the designation image generation means 51 rotates and displays the designation image 110. Also, at the time of tilting shown in (b), the designating image generating means 51 displays the designating image 110 by deforming the designating image 110 as if the sample was tilted. Furthermore, at the time of the position movement and the magnification change shown in (c), the designation image generation means 51 changes the size of the designation image 110 and displays the arrangement position in the entire visual field 115.

  Next, generation of coordinates in the coordinate generation unit 52 will be described. The coordinate generation unit 52 performs conversion based on the following expression from the orientation and position of the designation image 110 designated by the orientation position designation unit 60, and outputs the coordinates.

Here, x, y, and z are current coordinates, φ is a tilt angle, θ is a rotation angle, and X, Y, and Z are coordinates after conversion. This equation is for a case where the multi-axis stage 40 is configured by arranging the tilt mechanism 41, the Y-direction moving mechanism 42, the X-direction moving mechanism 43, the Z-direction moving mechanism 44, and the rotating mechanism 45 in this order from below. If the arrangement order of these mechanisms is changed, it is necessary to change them appropriately.

  The control unit 50 is configured as a computer including a CPU, a ROM, a RAM, an HDD, and the like, and executes the stored software on the CPU to perform image processing and coordinate conversion by a known method. Realize the function. Also, these functions can be implemented as hardware.

  Next, an imaging procedure of the scanning electron microscope 10 according to the embodiment will be described. FIG. 3 is a flowchart showing a procedure for observation of the scanning electron microscope, and FIG. 4 is a flowchart showing a procedure for setting the sample posture and position of the scanning electron microscope.

  In this example, the SEM image of the sample at the initial position and orientation is acquired, and the orientation and position of the sample to be imaged next by the operator are displayed while the instruction image created based on this image is displayed on the display device. specify.

  First, in the current visual field, the SEM image display control means 55 generates an SEM image based on the signal from the secondary electron detector 20, and the coordinate generation means 52 acquires the current coordinates of the multi-axis stage 40 (SA1). Next, the designation image generation means 51 generates designation image data based on the SEM image. The designation image data is stored in the designation image memory 56, and the designation image is displayed on the image display device 61 based on the designation image data (SA2). The operator operates the mouse 62 while observing the designation image to designate horizontal rotation movement, tilt movement, plane movement, and magnification change so that the designation image is in a desired state (SA3).

  In accordance with the designation by the operator, the designation image generation means 51 changes the image data stored in the captured image memory 57 (SA4), stores it in the designation image memory 56, and displays it on the image display device 61 (SA5). ). In accordance with the change of the designation image, the coordinate generation means 52 converts the coordinates (SA6) and stores them in the coordinate memory 54.

  When the required posture position is determined by the designation image 110, the operator presses a predetermined key button or clicks a specific location with the mouse. Thereby, the posture and position of the sample are determined, and the SEM image acquisition process is started (SA7). Then, the multi-axis stage drive control means 53 drives the multi-axis stage 40 based on the coordinates stored in the coordinate memory 54 and arranges (SA8) in the designated posture and position to perform imaging (SA9). ). The captured image data is stored in the captured image memory 57, and the SEM image of the posture and position designated by the designation image generation means 51 is displayed. Note that processing for sharpening an image by autofocusing or the like can be performed before imaging.

  Next, designation of the posture of the sample and the posture of the position using the mouse 62 will be described. FIG. 6 is a flowchart showing a sample orientation and position setting procedure of the scanning electron microscope according to the embodiment. When specifying the posture and position of the sample, first, an image for specification is displayed on the image display device 61 (SB1), and the wheel of the mouse 62 is rotated (SB2) to specify the rotational movement of the sample ( SB3). Similarly, the mouse 62 is right-dragged (SB4), and the tilt movement of the sample is designated (SB5). Further, the mouse 62 is left-dragged (SB6), the sample is moved in a plane, and the mouse 62 is rotated while being pressed (SB8), and the sample is rotated (SB9). The correspondence between these processes and mouse operations can be arbitrarily changed. In addition, other pointing devices such as a trackball can be used instead of the mouse.

  By these designations, the designation image generation means 51 changes the designation image and displays it on the image display device 61 (SB10). Finally, the coordinate generation means 52 of the multi-axis stage 40 based on this changed state. Coordinates are generated (SB11).

  The scanning electron microscope 10 according to the present embodiment can continuously display a plurality of images taken when the sample is moved. FIG. 7 is a flowchart showing an image display procedure of the scanning electron microscope. Such processing is to display changes in the observation image during movement as a moving image when the sample is rotated, tilted, moved in plane, or moved in combination.

  In this imaging process, first, the operator designates the posture and position (rotation, tilt, horizontal position, magnification, etc.) of the sample while viewing the designation image (SC1). Then, the coordinate generation means 52 calculates the coordinates of the multi-axis stage 40 in the posture and position and stores them in the coordinate memory 54. This processing (SC1, SC2) is performed at a plurality of predetermined locations (SC3), and the obtained position and orientation coordinates are sequentially stored in the coordinate memory 54.

  Next, the multi-axis stage drive control means 53 drives the multi-axis stage 40 with reference to a plurality of coordinates stored in the coordinate memory 54, and the SEM image display control means 55 from the secondary electron detector 20 at each coordinate. Imaging is performed based on the signal (SC4), and the image data is sequentially stored in the captured image memory 57 (SC5).

  When all the imaging is completed, the SEM image display control means 55 operates as a continuous display means according to an instruction from the operator, sequentially displays a plurality of images stored in the captured image memory 57 (SC7, SC8), and the process ends. .

  In this way, the scanning electron microscope 10 can sequentially display SEM images at a plurality of designated locations, and can display an observation image of the sample as a moving image.

  In the embodiment, the instruction image is generated based on the SEM image. However, the instruction image can be generated based on an enlarged image obtained by the optical microscope 30 disposed in the scanning electron microscope 10. When the instruction image is generated based on the optical microscope image, the instruction image can be displayed as a color image, which facilitates visual recognition.

  As described above, the scanning electron microscope 10 according to the present embodiment can operate the multi-axis stage 40 simply by intuitively operating the instruction image displayed on the image with the mouse, and can change the desired posture and position of the sample. An enlarged image can be obtained.

DESCRIPTION OF SYMBOLS 10 Scanning electron microscope 11 Lens tube 12 Electron beam source 13 Electron beam 14 Condenser lens 15 Deflection coil 16 Objective lens 17 Sample chamber 18 Sample 19 Charged particle 20 Secondary electron detector 30 Optical microscope 40 Multi-axis stage 41 Tilt mechanism 42 Y direction Movement mechanism 43 X-direction movement mechanism 44 Z-direction movement mechanism 45 Rotation mechanism 50 Control unit 51 Designation image generation means 52 Attitude position coordinate generation means 53 Multi-axis stage drive control means 54 Position / attitude coordinate memory 55 SEM image display control means 56 Designation Image memory 57 Imaged image memory 60 Posture position designation means 61 Image display device 62 Mouse 63 Keyboard 110 Designation image 111 Upper surface 112 One side surface 113 Other side surface 120 Observation image 121 Upper surface 123 Other side surface

Claims (9)

A multi-axis stage having a plurality of degrees of freedom including plane rotation and holding a sample in a predetermined posture and position based on a designated posture and position coordinates;
Based on the observation image of the sample acquired in the initial state, a designation image generating means for generating a designation image for displaying a photographed image of the sample in a desired posture and position;
A posture position designation means comprising a display device for displaying the designation image and a pointing device for designating the posture and position of the sample on the operation image of the display device;
Coordinate generation means for generating set coordinates of the multi-axis stage based on the designation image designated by the posture position designation means;
A sample stage apparatus comprising: a multi-axis stage drive control unit that drives and controls the multi-axis stage based on the set coordinates.   The sample stage apparatus according to claim 1, wherein the observation image of the sample in the initial state is obtained based on charged particles emitted from the sample irradiated with the electron beam.   The sample stage apparatus according to claim 1, wherein the observation image of the sample in the initial state is an optical image of the sample.   Coordinate storage means for storing one or more sets of coordinates designated by the target designation means is provided, and the multi-axis stage drive control means drives the multi-axis stage based on the coordinates stored in the coordinate storage means. The sample stage device according to any one of claims 1 to 3, wherein the sample stage device is provided.   The sample stage apparatus according to any one of claims 1 to 4, wherein the multi-axis stage has five degrees of freedom of tilt, Y direction, X direction, Z direction, and horizontal rotation. Irradiation means for scanning the sample with an electron beam;
6. A sample information generation unit that generates sample information based on charged particles from a sample irradiated with an electron beam; and the sample stage device according to claim 1. Electron beam equipment.   The electron beam apparatus according to claim 6, wherein the electron beam apparatus is a scanning electron microscope.   The electron beam apparatus according to claim 7, further comprising an optical microscope. Coordinate storage means for storing a plurality of sets of coordinates specified by a specified image, and image storage means for storing a plurality of observation images of the sample at each posture and position of the sample stage device set based on the plurality of coordinates When,
Continuous display means for continuously displaying the plurality of stored observation images;
The electron beam apparatus according to claim 6, further comprising: