JP2012114014A - Charged beam device, and image display method of charged beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged beam device which is capable of displaying an observation image with both low and high magnifications and with a short update time, a high degree of freedom, and stability, and capable of readily finding a desired observation position to be observed with a high magnification, with a good operability.SOLUTION: A scanning electron microscope has an input device 30, an image display device 40, and a controller 100. The scanning electron microscope uses an electron beam to 2D-scan a scan area on a sample which has been specified by the input device 30, detects charged particles from the scan area, and displays an observation image on the image display device 40 in synchronization with a scan signal of the electron beam. In the scanning electron microscope, the controller 100 gains a first observation image of a first scan area of a sample with a given magnification, and displays the first observation image in a first window of the image display device, the input device 30 is used to specify a position and an area in the first observation image thereby to set a second scan area, and the controller gains a second observation image of the second scan area with a magnification larger than the first magnification, and displays, on the image display device 40, a second window where the second observation image is drawn in combination with the display of the first window.

Description

  The present invention relates to a charged beam apparatus such as a scanning electron microscope, a semiconductor inspection apparatus, and a mask inspection apparatus, and an image method of the charged beam apparatus. In particular, two observation images with different magnifications can be displayed on one image display screen. The present invention relates to a charged beam apparatus and an image display method of the charged beam apparatus.

  A scanning electron microscope, which is a kind of the charged beam apparatus described above, scans a focused electron beam two-dimensionally in an observation region on a sample, and uses a detector to detect secondary electrons generated from the sample due to the electron beam. Detection is performed, and image data is generated based on the signal from the detector and the scanning signal of the electron beam, and an enlarged observation image of the observation region of interest is obtained. In such a scanning electron microscope, an enlarged image with a desired magnification can be obtained by controlling the deflection coil disposed in the electron beam path and changing the size of the scanning region on the sample.

  In order to obtain a high-magnification magnified image of the observation area of interest of the sample, an observation image with a magnification (low magnification) lower than the magnification (high magnification) to be observed is displayed in advance, and the sample device or on the sample is displayed. The scanning region of the electron beam is moved to search for an observation region in which a high-magnification observation image is obtained in the low-magnification observation image. Then, after determining the observation area, set the scanning area so that the center position of the determined observation area becomes the center of the observation image, and gradually increase the magnification of the electron microscope to the desired area. An enlarged image with a magnification is obtained.

  Here, when observing with such a scanning electron microscope, it is not always possible to obtain a desired observation image only by a series of operations such as exploration of the observation region at low magnification and observation at high magnification. In many cases, the operation of increasing the magnification while searching for the observation region by operating the sample device or the like at a low magnification is repeated, and it takes a lot of time for observation.

  Furthermore, in the case of a large sample such as a silicon wafer, it becomes more difficult to specify a minute observation region from a vast sample surface. In addition, when the sample is placed on the sample stage and moved mechanically, the observation point moves greatly only by slightly operating the sample stage, so that the setting of the observation point becomes more difficult. Furthermore, when observing the sample at an inclination, the image may change greatly from the case where the image is not inclined by the inclination, and the observation region is more difficult to specify.

  In order to cope with this, a charge beam device has been proposed that simultaneously displays a low-magnification image and a high-magnification image on an image display device. In Patent Document 1, a sample is irradiated with an irradiation beam, a means for scanning the irradiation beam, a means for repeatedly changing the scanning range into a plurality of stages, and each sample signal obtained by scanning over the plurality of magnifications are detected. And means for independently displaying a plurality of sample images based on the respective sample detection signals at the same time, with two display devices and two display areas in which the display screen is divided in half, with different magnifications. An electron beam apparatus for displaying the image is described.

  Patent Document 2 discloses a means for scanning a first region of a sample with an irradiation line, a means for detecting information obtained from the first region, and a detection signal based on the detected information signal. A second image in which a first image of the first region is displayed and the second region in the first region is simultaneously enlarged to a corresponding portion in the first image during the sample scanning. A charged beam apparatus comprising means for displaying as an image.

Japanese Patent Publication No.46-24459 Japanese Patent Publication No.53-40478

  However, the method disclosed in Patent Document 1 has a double image update time for displaying one screen in order to display low-magnification and high-magnification images with normal image quality (size and resolution). In addition, there is a problem that the display positions of both the high and low screens are fixed, and the operator needs to perform operations while changing the line of sight while comparing the two screens.

  In addition, since the one described in Patent Document 2 changes the scanning trajectory of the electron beam during horizontal scanning to capture an image of two magnifications of a high-magnification image, excessive overshoot occurs at the start point and end point of the trajectory change. And undershoot occur, and there is a problem that image distortion is large and practicability is poor.

  The techniques described in Patent Document 1 and Patent Document 2 are difficult to maintain image quality equivalent to that of normal observation with the image display technology at that time, and the apparatus becomes complicated and operability is difficult. Then did not spread.

  Therefore, the present invention can stably obtain an observation image with both low and high magnifications in a short update time, and can display an observation image with high magnification with a high degree of freedom, and has high operability with high operability. It is an object of the present invention to provide a charged beam apparatus capable of quickly exploring a desired observation position and an image display method for the charged beam apparatus.

  In order to solve the above-mentioned problems, the invention of claim 1 is directed to a charged beam source for generating a charged beam, a deflection coil for two-dimensionally scanning the charged beam in a scanning region on a sample based on a scanning signal, and the scanning signal. A scanning control device that outputs charged particles from the sample, outputs a detection signal, a display device that displays an observation image based on the image signal, and the scanning signal and the detection signal A charge beam apparatus comprising: an image display control device that outputs the image signal; and an input device that inputs the scan signal and a setting value for generating the image signal. As a signal, a first scanning signal for scanning the first scanning region and a second scanning signal for scanning a second scanning region located in the first scanning region and having a size smaller than the first region are 1 or The image display control device alternately outputs every several frames, and the image display control device displays a first image signal displayed in a first window for displaying an enlarged image of the first scanning region on the display device, and an image of the second scanning region. Generating a second image signal for displaying the second window on the second window, and combining the first image signal and the second image signal to display the second window on the first window on the display device. Output as an image signal, and the input device designates the position of the display image of the display device, thereby setting the scan setting value for designating the scan position and scan range in the sample in the second scan region as the set value And a display setting value for designating a display position and a display range in the display device of the second window.

  According to a second aspect of the present invention, in the charged beam apparatus according to the first aspect, a mouse device for designating coordinates on a sample by designating coordinates on each window displayed on the display device by the input means, It is a pointing device including a trackball device.

  According to a third aspect of the present invention, in the charged beam device according to the first or second aspect, the image display control device outputs the image signal without delay in response to generation of the scanning signal of the scanning control device. It is characterized by doing.

  According to a fourth aspect of the present invention, in the charged beam apparatus according to any one of the first to third aspects, the operation control device includes an autofocus device that automatically adjusts the focus of the charged particles, and the display The control device includes an image quality adjustment device that automatically adjusts the display image quality of the display device, and the autofocus device and the image quality adjustment based on an image displayed in one of the displayed first window and second window. It is characterized by comprising adjustment means characterized by comprising adjustment means for adjusting at least one of the devices.

  According to a fifth aspect of the present invention, in the charged beam device according to any one of the first to fourth aspects, the input device is an image of a designated one of the first window and the second window. Can be output to the display control device and the image display device.

  According to a sixth aspect of the present invention, in the image display method of the charged beam device, the scanning region on the sample designated by the input device is two-dimensionally scanned with the charged beam, and charged particles from the scanning region are detected to detect the charged region. In the image display method of a charged beam apparatus for displaying an observation image on an image display device in synchronization with a scanning signal of a charged beam, a step of acquiring a first observation image at a predetermined magnification in a first scanning region of a sample, and the image display device Displaying the first observation image in the first window, setting the second scanning region by designating the position and region in the first observation image with the input device, and the second scanning region A step of acquiring a second observation image having a magnification larger than the first magnification and a second window for drawing the second observation image on the image display device combined with the display of the first window. And wherein further comprising the steps of, a.

  According to a seventh aspect of the present invention, in the image display method of the charged beam apparatus according to the sixth aspect, the second window is enlarged to an arbitrary size while maintaining the center position and magnification of the second observation image. It is characterized by including the process to do.

  According to the present invention, since the scanning of the charged beam on the sample is alternately performed for each frame, the display device displays a high magnification image superimposed on the first window displaying the low magnification image and the first window. The second window to be displayed is displayed well. In addition, the position and display range of the high-magnification image displayed in the second window on the sample and on the screen can be determined simply by specifying and operating the position on the image of the first window displayed on the image display device with the input device. Therefore, an observation image with both low and high magnification can be obtained with a simple operation. Therefore, a high-magnification observation image can be displayed with a high degree of freedom, and a desired observation position with a high magnification can be quickly searched with good operability.

It is a schematic diagram which shows schematic structure of the scanning electron microscope which concerns on the example of embodiment. It is a schematic diagram which similarly shows the dimension and position of the 1st window and 2nd window in a display apparatus. It is a schematic diagram which similarly shows the dimension and position of the 1st scanning area | region and 2nd scanning area | region on a sample. It is a block diagram which similarly shows the structure of the control system of a scanning electron microscope. It is a block diagram which similarly shows the structure of the operation control apparatus and image display control apparatus of a scanning electron microscope. Similarly, the waveform of a scanning signal is shown, (a) is a schematic diagram showing a horizontal scanning signal, and (b) is a schematic diagram showing a vertical scanning signal. It is a flowchart which similarly shows the display procedure of the high magnification image of a scanning electron microscope. It is a schematic diagram which similarly shows the relationship between a sample and a picked-up image and a scanning signal. It is a schematic diagram which similarly shows the relationship between a sample and a picked-up image and a scanning signal. It is a flowchart which similarly shows the display procedure of the high magnification image of a scanning electron microscope. It is a flowchart which similarly shows the focus adjustment and image quality adjustment of a scanning electron microscope.

  Hereinafter, an example of an embodiment of a charged beam apparatus according to the present invention will be described with reference to the drawings. Hereinafter, although a scanning electron microscope is described as an example as an embodiment, the present invention can be applied to other apparatuses such as a semiconductor inspection apparatus and a mask inspection apparatus as a charged beam apparatus.

  FIG. 1 is a schematic diagram showing a schematic configuration of a scanning electron microscope according to an embodiment. The scanning electron microscope 10 converges an electron beam 13 as a charged beam generated from an electron beam source 12, which is a charged beam source in the upper part of the lens barrel 11, by a condenser lens 14, and deflects and scans it by a deflection coil 15. The convergence and focus are adjusted by the lens 16, and the sample 18 in the sample chamber 17 is two-dimensionally scanned. Note that the sample 18 is disposed on the sample stage 21 and can be moved to an arbitrary position or inclined at an arbitrary angle.

  The scanning electron microscope 10 includes a control device 100, an input device 30, and an image display device 40. The control device 100 generates a scanning signal of the deflection coil 15 and a control signal of the objective lens 16, and also displays a scanning electron microscope image (SEM image) in synchronization with the signal from the detector 20 and the scanning signal. It is displayed on the device 40. The input device 30 also receives various setting values designated by the operator for the control device 100, that is, scanning setting values for scanning the electron beam, and display setting values for designating the enlarged image display region in the image display device. input. In this example, the input device 30 includes a mouse device that operates by designating coordinates on an image displayed on the image display device 40, and a keyboard that inputs numerical values, characters, and symbols. In addition to the mouse device, other pointing devices such as a trackball device can be used. The image display device 40 can use a plasma display or CRT in addition to a liquid crystal display (LCD).

  In the scanning electron microscope 10, charged particles 19 such as secondary electrons and reflected electrons generated from the sample 18 are detected by a detector 20. The signal from the detector 20 is synchronized with the scanning signal of the deflection coil 15 by the control device 100 and a scanning electron microscope image (SEM image) is displayed on the image display device 40.

  The scanning electron microscope 10 according to the present embodiment displays on the image display device 40 a first window that displays a low-magnification observation image and a second window that displays a high-magnification observation image. FIG. 2 is a schematic diagram showing dimensions and positions of the first window and the second window in the display device according to the embodiment. FIG. 3 is a schematic diagram showing dimensions and positions of the first scanning area and the second scanning area in the sample. It is.

  As shown in FIG. 2, a first window 51 and a second window 52 are displayed on the image display device 40. Hereinafter, the display size of the first window 51 is HL × VL, the size of the second window 52 is Hh × Vh smaller than the first window 51, and the center position of the second window 52 is the center position of the first window 51. It is assumed to be located at a point (Vc, Hc) in the HV coordinate system with the center O1 of the first window as the origin.

  Further, as shown in FIG. 3, a first scanning region 61 for acquiring a low magnification image and a second scanning region 62 for acquiring a high magnification image are set on the surface of the sample 18. In FIG. 3, three types of second scanning regions 62, 63, and 64 having different double interest rates are displayed. In FIG. 3, the magnification of the scanning area indicated by reference numeral 62 is indicated as 2, the magnification of the scanning area indicated by reference numeral 63 is indicated by 4, and the magnification of the scanning area indicated by reference numeral 64 is indicated by 8. Hereinafter, the size of the first scanning region 61 is XL × YL, the size of the second scanning region 62 with a magnification of 2 is XH × YH, and the center position of the second scanning region 62 is the center of the first scanning region 61. It is assumed that it is located at a point (Xc, Yc) in the XY coordinate system with O2 as the origin. Note that the sizes of the second scanning region 63 with a magnification of 4 and the second scanning region with a magnification of 8 are set smaller according to the magnification.

  In the scanning electron microscope 10 according to this example, an image obtained in the first scanning region 61 is displayed in the first window 51, and an image obtained in the second scanning region 62 is displayed in the second window 52. Then, the second scanning area 62 is moved to an arbitrary position in the first scanning area 61 by the designation from the input device 30, and the second window 52 is displayed at a corresponding position in the first window 51.

  The size of the first scanning area 61 is set according to the magnification of the image acquired as a low magnification. Furthermore, as described above, the size of the second scanning region 62 is set according to the magnification for the low-magnification image acquired as the high magnification.

  Furthermore, in the scanning electron microscope 10 according to the present embodiment, the size of the second window 52 can be arbitrarily set. That is, the size of the second window 52 can be changed while the magnification is fixed, and the size of the second scanning region 62 is also changed with the change of the size of the second window 52.

  Therefore, the control device 100 uses the deflection coil 15 as a scanning signal to scan the first scanning region 61 for scanning the first scanning region 61 for acquiring a low magnification image, and the second scanning region for displaying the high magnification image. The second scanning signal S2 for scanning 62 is alternately output every frame. The first scanning signal S1 and the second scanning signal S2 can be output not only for each frame but for each arbitrary frame.

  In addition, the control device 100 displays the first image signal displayed in the first window 51 that displays the enlarged image of the first scanning region 61 on the image display device 40 and the image of the second scanning region 62 on the second window 52. A second image signal to be generated, and the first image signal and the second image signal are combined and displayed as an image signal so that the second window 52 is superimposed on the first window 51 on the display device. .

  Further, the input device 30 includes a mouse device for inputting a setting value by designating a position of a display image of the image display device 40, and a keyboard for inputting a numerical value such as a magnification and a character symbol. A scanning setting value that specifies the first scanning area 61 and the second scanning area 62 and a display setting value that specifies the magnification, size, and position of the first window 51 and the second window 52 in the image display device 40 are output.

  Note that the mouse device of the input device 30 designates the inside of the first window 51 in a state where the size of the first scanning region 61 and the scanning position in the sample are set as initial values. The coordinates (Xc, Yc) and the scanning range (XH, YH) in the first scanning area 61 can be designated. As a result, a display setting value for designating the display position and display range of the second window 52 in the first window 51 is output.

  Next, the control of the scanning electron microscope 10 will be described in detail. 4 is a block diagram showing the configuration of the control system of the scanning electron microscope according to the embodiment, FIG. 5 is a block diagram showing the configuration of the operation control device and the image display control device of the scanning electron microscope according to the embodiment, and FIG. The waveform of a scanning signal is shown, (a) is the schematic which shows a horizontal scanning signal, (b) is the schematic which shows a vertical scanning signal. In FIG. 6, for the convenience of drawing, the number of horizontal scans is smaller than the actual number.

  As shown in FIG. 4, the control device 100 includes a scan drive device 110 that outputs a scan signal to the deflection coil 15, a scan control device 120 that controls the scan drive device 110, and noise processing and AD of the signal from the detector 20. A signal processing device 130 that performs conversion processing, an image display control device 140 that receives a signal from the signal processing device 130 and generates display image data of the image display device 40, and an auto that is connected to the objective lens 16 and performs autofocus processing. A focus device 150, an image quality adjustment device 160 that performs automatic image quality adjustment, and a sample stage control device 170 that performs drive control of the sample stage 21 are provided. By specifying the displayed first window 51 or second window 52, the autofocus device 150 and the image quality adjustment device 160 can adjust the image of the designated designated window to an optimum state.

  As shown in FIG. 5, the scanning drive device 110 includes a horizontal scanning signal generation device 111 that generates a horizontal scanning signal and a vertical scanning signal generation device 112 that generates a vertical scanning signal under the control of the scanning control device 120. Prepare.

  As shown in FIG. 5, the scan control device 120 includes a first scan setting storage unit 121, a second scan setting storage unit 122, and a scan switching device 123. The first scan setting storage unit 121 stores data for generating a first scan signal for acquiring a low-magnification image. The second scan setting storage unit 122 stores a first scan signal for acquiring a high-magnification image. Data for generating two scanning signals is stored.

  The scan switching device 123 switches the setting values in the first scan setting storage unit 121 and the second scan setting storage unit 122 for each frame of the image display device. As a result, the scanning drive device 110 outputs a horizontal scanning signal (FIG. 6A) and a vertical scanning signal (FIG. 6B) as shown in FIG. In the example shown in FIG. 6, the first scanning signal S1 and the second scanning signal S2 are alternately output for each frame. In this example, the scan switching device 123 alternately outputs each scan signal for each frame number, but this setting can be freely changed. That is, after outputting the first scanning signal S1 by a predetermined number of frames, the second scanning signal S2 is output by a predetermined number of frames. For example, after outputting the first scanning signal S1 by one frame, the second scanning signal is output over a plurality of frames. S2 can be output.

  As shown in FIG. 5, the image display control device 140 includes an image generation device 141, an output switching device 142, a low-magnification image memory 143 that is a first image memory, and a high-magnification image memory 144 that is a second image memory. And an image composition device 145. The image generation device 141 includes a first scanning region 61 based on the signal of the detector 20 from the signal processing device 130 and the first scanning signal S1 and the second scanning signal S2 that are alternately output from the scanning control device 120. The low magnification image and the high magnification image of the second scanning region 62 are alternately output.

  The low-magnification image memory 143 stores the first image signal of the first scanning area 61 output from the image generation device 141 as a low-magnification image. Further, the high-magnification image memory 144 stores the second image signal of the second scanning area 62 output from the image generation device 141 as a high-magnification image. The output switching device 142 switches the output of the image generation device 141 to the low magnification image memory 143 and the high magnification image memory 144 and outputs the result. The image composition device 145 combines the low-magnification image stored in the low-magnification image memory 143 and the high-magnification image stored in the high-magnification image memory 144, the low-magnification image in the first window 51, and the high-magnification image in the second window. An image signal for displaying is output.

  In the scanning electron microscope 10 according to the present embodiment, such a control device 100 is constituted by a computer having a CPU, HDD, RAM, ROM, and various IO interfaces, and software stored in the HDD and ROM. Are executed by the CPU using the RAM as a work area, thereby realizing functions such as processing, setting, and waveform generation of each device.

  Next, the basic operation of the control device 100 will be described. Hereinafter, a low-magnification image is displayed as a first window 51 on the image display device 40 in a range of HL × VL, and a high-magnification image is displayed as a second window 52 in a part of the Hh × Vh range (see FIG. 2). ). In the present embodiment, in order to simultaneously display a low-magnification image and a high-magnification image, as shown in FIG. 3, an XL × YL first scanning area 61 set at a predetermined position on the sample, and the first scanning area The XH × YH second scanning area 62 set in 61 is alternately scanned for each display frame of the image display device 40.

  Here, the ratio HL / XL = VL / YL between the size of the screen and the size of the scanning area on the sample is the magnification of the low-magnification image displayed in the first window 51, which is the magnification of a normal scanning electron microscope. It becomes.

  When displaying a high-magnification image in the second window 52, when displaying on the screen at the same pixel density as the low-magnification image displayed in the first window 51, the first window 51 and the second window 52 overlap, If an image of a hidden portion of one window 51 is also captured, the total number of pixels to be captured is a value proportional to the total area of the display images of the low magnification image and the high magnification image.

  For example, if the display range of the high-magnification image is 1/4 of the low-magnification side, the area of the high-magnification image is 1/16. Since the update time of both images is proportional to the total number of pixels, the image update time in the above case is 1 + 1/16 = 17/16 in the case of only a low-magnification image.

  In this embodiment, if the display area on the high-magnification side is suppressed to a certain value, the low-magnification image and the high-magnification image are hardly increased compared to the time required for displaying the first window 51, as compared with the time required for displaying the first window 51. Images can be displayed simultaneously. This relationship does not depend on the magnification of the image on the high magnification side, and is the same regardless of the magnification of the image on the high magnification side. On the other hand, when the same function is realized using so-called digital zoom, all pixels of the low-magnification side image are captured at a pixel density that can be practically obtained by cutting out only the high-magnification part. It is necessary to capture the number of pixels corresponding to the magnification of the image, and the image update time becomes extremely long. For example, if the high magnification side is set to 4 times the low magnification side, the total number of pixels is 4 × 4 = 16 times, and the image update time is 16 times, which is not practical.

  In order to capture a high-magnification image, the target area of the low-magnification image on the sample is finely scanned as shown in FIG. 3, but the size of scanning on the high-magnification side is the size of the high-magnification image displayed on the screen. The value is proportional to the size and inversely proportional to the magnification for the low magnification image.

If the magnification of the high-magnification image relative to the low-magnification image is M and the high-magnification side scanning width is XH × YH,
XH = XL × Hh / HL / M
YH = YL × Vh / VL / M
It becomes.

  The position on the sample from which a high-magnification observation image is desired is selected by moving the high-magnification image display area HhxVh on the display screen shown in FIG. At this time, if the second scanning signal S2 is generated by changing the center value of the first scanning signal S1 by Xc and Yc according to Hc and Vc obtained from the mouse device, as shown in FIG. The second scanning region 62 set at the center position Xc, Yc can be scanned on the sample.

  The size of the second window 52 (the size of the field of view) for displaying the high-magnification side image is specified by dragging around (HhxVh) of the second window 52. At this time, the amplitudes XH and YH of the second scanning signal S2 in FIG. 6 may be changed according to the values Hh and Vh obtained from the screen. Thereby, the (XH × YH) range of the second scanning region 62 on the sample in FIG. 3 is scanned.

  The magnification of the high-magnification image relative to the low-magnification image can be changed in inverse proportion to the amplitude of the second scanning signal S2 by reducing the amplitude of the second scanning signal S2 while maintaining the size of the display area of the high-magnification image. At this time, the second scanning region is reduced like the second scanning region 63 and the second scanning region 64 in FIG. This setting can be performed, for example, by inputting a numerical value from a keyboard or operating a wheel of a mouse device.

  Next, an operation procedure of the scanning electron microscope 10 according to the embodiment will be described. When observing a sample with the scanning electron microscope 10, first, a low-magnification image is set. The setting of the low-magnification image is the same as the case of observing the sample with a normal scanning electron microscope. As a result, XL, YL, HL, and VL are set in the first scan setting storage unit 121, and a low-magnification image of the first scan area is displayed in the first window 51 displayed on the image display device 40. Next, in this state, a high-magnification image of the second scanning region 62 is displayed on the second window 52 of the image display device 40.

  FIG. 7 is a flowchart showing a procedure for displaying a high-magnification image. First, the display state of the high-magnification image is designated. This is based on three types of settings, that is, designation of the magnification of the high-magnification image (x2, x4, x8, etc.) relative to the low-magnification image, designation of the display position of the high-magnification image, and designation of the window size of the high-magnification image This is performed by selecting a process to be executed (step ST21). This selection is performed by performing a predetermined operation with a mouse device or a keyboard, and the selection of processing and the setting of each condition can be changed later (step ST28).

  The magnification of the high-magnification image is set by inputting the magnification M from the keyboard (step ST22). Thereby, the magnification M of the high-magnification image is set (step ST23). This magnification can also be specified by operating the mouse wheel.

  The designation of the display position of the high-magnification image is performed by dragging the second window 52 displaying the high-magnification image with a mouse and moving it to a desired position (step ST24). Thereby, the values Hc, Vc, Xc, Yc are set in the second scanning setting storage unit 122 (step ST25).

  The window size of the high-magnification image is designated by dragging the outline around the second window 52 displaying the high-magnification image with the mouse and changing the size (step ST26). Thereby, the values Hh, Vh, XH, and YH are set in the second scan setting storage unit 122 (step ST27).

  When the above processing is performed, the setting information stored in the first scan setting storage unit 121 and the second scan setting storage unit 122 is alternately output from the scan control device 120 to the scan drive device 110, and the scan drive device 110. Generates the first scanning signal S1 and the second scanning signal S2 alternately. Thereby, based on the signal from the sample detected by the detector 20, the image display control device 140 displays the low-magnification image of the first scanning region 61 in the first window 51 of the image display device 40 and the second window 52 of the second. A high-magnification image of the two scanning area 62 is displayed (step ST29). In the scanning electron microscope 10, the condition change for acquiring a high-magnification image from the input device 30 is immediately processed, and an image associated with the condition change is displayed on the image display device 40 in real time.

  The change in the captured image and the scanning signal accompanying the change in the conditions of the second window 52 display will be specifically described. This example is a case where processing for expanding the display range of the second window is performed (step ST26 and step ST27 in FIG. 7). FIG. 8 is a schematic diagram illustrating the relationship between the sample and the captured image and the scanning signal in the scanning microscope according to the embodiment, and FIG. 9 is a schematic diagram illustrating the relationship between the sample and the captured image and the scanning signal in accordance with the setting change in the scanning electron microscope. FIG.

  In the example shown in FIG. 8, when the first scanning region 71 and the second scanning region 72 of the sample are scanned based on the first scanning signal S1 and the second scanning signal S2, the first scanning region is displayed in the first window 81. 71, and a high-magnification image of the second scanning region 72 is displayed in the second window 82. In this state, the outline around the second window 82 in FIG. 8 is dragged with the mouse device so that it is enlarged in the vertical and horizontal directions as in the second window 83 in FIG. Then, the vertical and horizontal amplitudes of the second scanning signal S2 increase from Xa1, Ya1 to Xa2, Ya2, and accordingly, a high-magnification image of the enlarged range is displayed on the second window 83.

  Next, a case where a high-magnification image is displayed on the entire surface of the image display device 40 without changing the center position of the high-magnification image displayed in the second window 52 will be described. FIG. 10 is a flowchart showing an image display method of the scanning electron microscope. For this reason, the control device 100 performs the following processing when an instruction from the input device 30, for example, a specific key is pressed.

  First, a low-magnification image is displayed on the first window 51 and a high-magnification image is displayed on the second window 52 of the image display device 40 (step S31). Next, the low magnification image displayed in the first window 51 is selected by double clicking with the mouse device (step ST32). Then, XH = XL / M, YH = YL / M, Xc = Xc (no change), Yc = Yc (no change), Hh = HL, Vh in the second scan setting storage unit 122 of the scan control device 120. = VL, Vc = 0, and Hc = 0 are set (step ST33), and a window of size HL × VL is displayed on the display screen of the image display device, and the specified location is placed in this window as it is. The second window 52 is enlarged to the size of the first window 51, and a high-magnification image is displayed (step ST34).

  Next, the focus and image quality adjustment of the scanning electron microscope will be described. FIG. 11 is a flowchart showing focus adjustment and image quality adjustment of the scanning electron microscope according to the embodiment. The scanning electron microscope 10 according to the present embodiment performs focus and image quality adjustment so that one of the high-magnification image and the low-magnification image can be optimally displayed. FIG. 10 is a flowchart showing an image display method of the scanning electron microscope according to the embodiment. In this example, the focus adjustment by the autofocus device 150 and the image quality adjustment by the image quality adjustment device 160 are optimum for one of the selected magnifications.

  First, according to the procedure described above, a low-magnification image is displayed on the first window 51 and a high-magnification image is displayed on the second window 52 of the image display device 40 (step S41). Next, by operating the mouse device or the keyboard, one magnification for performing focus adjustment and image quality adjustment is selected (step ST42). Then, by inputting this instruction to the autofocus device 150 and the image quality adjustment device 160, the autofocus device 150 and the image quality adjustment device 160 analyze the image of the selected magnification, and based on the analysis result, the focus is obtained by a known method. Adjustment (step ST43) and image quality adjustment are performed (step ST44).

  As described above, according to the scanning electron microscope 10 according to the present embodiment, the electron beam 13 on the sample 18 is scanned alternately in the two scanning regions for each frame, and the image display device 40 has a low-magnification image. The first window 51 that displays the image and the second window 52 that displays the high-magnification image superimposed on the first window are displayed favorably. In addition, the high magnification image displayed on the second window 52 on the sample and on the screen can be simply specified and operated on the image of the first window 51 displayed on the image display device 40 by the input device 30. The position and display range can be changed, and an observation image with both low and high magnifications can be stably obtained in a short update time. Therefore, a high-magnification observation image can be displayed with a high degree of freedom, and a desired observation position with a high magnification can be quickly searched with good operability.

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 Detector 21 Sample stage 30 Input device 40 Image display device 51 First window 52 First 2 window 61 1st scanning area 62, 63, 64 2nd scanning area 71 1st scanning area 72 2nd scanning area 81 1st window 82 2nd window 83 2nd window 100 Controller 110 Scan driver 111 Generation of horizontal scanning signal Device 112 Vertical scanning signal generator 120 Scan control device 121 First scan setting storage unit 122 Second scan setting storage unit 123 Scan switching device 130 Signal processing device 140 Image display control device 141 Image generation device 142 Output switching device 143 Low magnification image Memory 144 High magnification image memory 145 150 autofocus device 160 image-quality adjusting apparatus 170 sample stage controller

Claims (7)

A charged beam source for generating a charged beam, a deflection coil for two-dimensionally scanning the charged beam in a scanning region on the sample based on a scanning signal, a scanning control device for outputting the scanning signal, and charged particles from the sample A detector that detects the detection signal and outputs a detection signal; a display device that displays an observation image based on the image signal; an image display control device that outputs the image signal based on the scanning signal and the detection signal; In a charged beam device comprising: an input device for inputting a set value for generating a scanning signal and the image signal;
The scanning control device scans a first scanning signal for scanning the first scanning region as the scanning signal, and a second scanning region located in the first scanning region and having a size smaller than the first region. The scanning signal is output alternately every one or a plurality of frames,
The image display control device displays a first image signal to be displayed on a first window for displaying an enlarged image of the first scanning region on the display device, and a second to display an image of the second scanning region on a second window. The image signal is generated, and the first image signal and the second image signal are combined and output as the image signal so that the display device displays the second window on the first window,
The input device designates a position of a display image of the display device, thereby setting, as the set value, a scan set value for designating a scan position and a scan range in the sample in the second scan region, and the second window A charged beam apparatus characterized by outputting a display setting value for designating a display position and a display range in the display apparatus.   2. The pointing device according to claim 1, wherein the input device is a pointing device including a mouse device and a trackball device that designate coordinates on a sample by designating coordinates on each window displayed on a display device. Charged beam device.   3. The charged beam apparatus according to claim 1, wherein the image display control device outputs the image signal without delay in response to generation of a scanning signal of the scanning control device. The operation control device includes an autofocus device that automatically adjusts the focus of charged particles,
The display control device comprises an image quality adjustment device for automatically adjusting the display image quality of the display device,
An adjusting means for adjusting at least one of the autofocus device and the image quality adjusting device based on an image displayed in one of the displayed first window and second window; The charged beam apparatus according to any one of claims 1 to 3, wherein:   The input device can output to the display control device and the image display device a set value for displaying an image of one of the designated windows of the first window and the second window on the entire surface of the display device. The charged beam apparatus according to any one of claims 1 to 4, wherein: A scanning region on the sample designated by the input device is two-dimensionally scanned with a charged beam, charged particles from the scanning region are detected, and an observation image is displayed on the image display device in synchronization with the scanning signal of the charged beam. In the image display method of the charged beam apparatus, obtaining a first observation image at a predetermined magnification in the first scanning region of the sample;
Displaying the first observation image in a first window of the image display device;
Setting a second scanning region by designating a position and a region in the first observation image with the input device;
Obtaining a second observation image having a magnification larger than the first magnification of the second scanning region;
Displaying a second window for drawing the second observation image on the image display device in combination with the display of the first window;
An image display method for a charged beam apparatus. The image display method of the charged beam apparatus according to claim 6, further comprising a step of enlarging and displaying the second window to an arbitrary size while maintaining a center position and a magnification of the second observation image.