Patent Publication Number: US-10763074-B2

Title: Charged particle beam apparatus, observation method using charged particle beam apparatus, and program

Description:
TECHNICAL FIELD 
     The present invention relates to an observation technology of a charged particle beam apparatus. 
     BACKGROUND ART 
     A charged particle beam apparatus is an apparatus that irradiates a sample with a charged particle beam and performs observation, and thus it is necessary to set an observation object in a vacuum in order to prevent charged particles from scattering. Therefore, there has been known an observation auxiliary function of displaying an image captured at lower magnification than observation magnification, in order to identify an observation position on a sample, in a case where it is not possible to recognize the observation sample with naked eyes, and providing the observation position on the captured image having a low magnification. 
     There are PTL 1 and PTL 2 as background art of this technical field. In PTL 1, description of “means for displaying an observation frame superimposed on an optical image of a sample, and the like” is provided. In addition, PTL 2 discloses that “it is possible to provide a scanning electron microscope that is capable of obtaining a very low-magnification image in a short time and with a small memory capacity and performing a search for a visual field by wide-field image observation, during the search for a visual field in a condition that it is not possible to observe the entire region of a sample even at the lowest magnification”. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP-A-10-3875 
     PTL 2: JP-A-7-130319 
     SUMMARY OF INVENTION 
     Technical Problem 
     The inventors of this application have obtained the following findings, as a result of an intensive study on a method for identifying and setting an observation position of a sample by intuition and with high accuracy in a charged particle beam apparatus. 
     In the related art, in observation by using the charged particle beam apparatus, the following methods are used as means for identifying an observation position of a sample set in a sample chamber in a vacuum. 
     (1) Provide one image having a low magnification, and illustrate an observation position on the low-magnification image. 
     (2) Image a plurality of low-magnification images and illustrate observation positions by switching the low-magnification images depending on magnification. 
     (3) Capture images in a designated continuous region, generate a low-magnification image by connecting the images, and illustrate an observation position of a sample. 
     For example, the apparatus in PTL 1 provides an observation position on a sample by displaying a frame indicating a current observation position on one low-magnification optical image. The apparatus in PTL 2 acquires a plurality of images while capturing and stage moving are alternately performed and finally aligns the images based on coordinate, thereby generating one low-magnification image for a search for a visual field. 
     However, in a method for providing the low-magnification image or the observation position on the connected low-magnification image, it is difficult to identify the observation position in a case where a magnification of a visual field displayed on a screen of the optical image or the connected image significantly differs from a magnification of an observation field in which observation is currently performed. In addition, also in a method for providing an observation position by switching a plurality of low-magnification images, an image, on which the observation position is to be displayed, is not suitable for the magnification at which the image is currently observed in some cases. 
     Hence, the present invention provides a technology in which it is possible to provide an observation position even when a magnification at which current observation is performed (a magnification of an observation image) significantly differs from a magnification of an image on which the observation position is displayed. 
     Solution to Problem 
     For example, in order to solve such a problem described above, configurations described in claims are adopted. This application includes a plurality of means which solve the problem described above and, as an example thereof, there is provided a charged particle beam apparatus including: an optical system that irradiates a sample mounted on a sample stage with a charged particle beam; at least one detector that detects a signal which is generated from the sample; an imaging device that acquires an observation image from the detected signal; a mechanism for changing observation positions in the sample which has at least one of a stage that moves the sample stage and a deflector that changes an irradiation position of the charged particle beam; a display unit that displays an operation screen provided with an observation image displaying portion that displays the observation image and an observation position displaying portion that displays an observation position of the observation image; and a controller that controls display processing of the operation screen. The controller causes a plurality of observation position displaying images at different magnifications to be superimposed and displayed on the observation position displaying portion, based on magnifications and coordinates at which the observation images are acquired. 
     In addition, according to another example, there is provided an observation method performed by using a charged particle beam apparatus, the method including: a step of irradiating a sample mounted on a sample stage with a charged particle beam by an optical system; a step of detecting a signal that is generated from the sample by at least one detector; a step of acquiring an observation image from the detected signal by an imaging device; a step of displaying, by a controller on a display unit, an operation screen provided with an observation image displaying portion that displays the observation image and an observation position displaying portion that displays an observation position of the observation image; and a step of superimposing and displaying a plurality of observation position displaying images at different magnifications on the observation position displaying portion, by the controller based on magnifications and coordinates at which the observation images are acquired. 
     In addition, according to still another example, there is provided a program that causes an information processing device including a calculation unit, a storage unit, and a display unit to execute a process of displaying an observation image obtained by a charged particle beam apparatus, the program causing the calculation unit to execute a display process of displaying, on the display unit, an operation screen provided with an observation image displaying portion that displays the observation image and an observation position displaying portion that displays an observation position of the observation image, and a display process of superimposing and displaying a plurality of observation position displaying images at different magnifications on the observation position displaying portion, based on magnifications and coordinates at which the observation images are acquired. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide an observation position even when a magnification at which current observation is performed (a magnification of an observation image) significantly differs from a magnification of an image on which the observation position is displayed. Additional features related to the present invention are clarified in the description of the present specification and accompanying features. In addition, problems, configurations, and effects other than those in above description are clarified in the following description of examples. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates an example of a schematic diagram of a charged particle beam apparatus according to the present invention. 
         FIG. 2  illustrates an example of a configuration of displaying an observation position on an operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 3  illustrates an example of the configuration of displaying the observation position on the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 4  illustrates an example of the configuration of displaying the observation position on the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 5  illustrates an example of the configuration of displaying the observation position by using a plurality of images on the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 6  illustrates an example of the configuration of displaying the observation position by using the plurality of images on the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 7  illustrates the operation screen before a rotating operation by a stage or an optical system, in the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 8  illustrates the operation screen after the stage rotates the orientation of the sample, in the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 9  illustrates the operation screen after the rotating operation by the optical system, in the operation screen of the charged particle beam apparatus according to the present invention. 
         FIG. 10  illustrates an example of a basic configuration of an observation position displaying portion according to the present invention. 
         FIG. 11  is a diagram illustrating an operation of a deflection degree displaying indicator of the observation position displaying portion according to the present invention. 
         FIG. 12  illustrates an example of a configuration of displaying a plurality of images obtained by different imaging systems in the observation position displaying portion according to the present invention. 
         FIG. 13  illustrates a first example of controlling a magnification of an observation image and a magnification of the observation position displaying portion in conjunction with each other. 
         FIG. 14  illustrates the first example of controlling the magnification of the observation image and the magnification of the observation position displaying portion in conjunction with each other. 
         FIG. 15  illustrates the first example of controlling the magnification of the observation image and the magnification of the observation position displaying portion in conjunction with each other. 
         FIG. 16  illustrates a second example of controlling the magnification of the observation image and the magnification of the observation position displaying portion in conjunction with each other. 
         FIG. 17  illustrates the second example of controlling the magnification of the observation image and the magnification of the observation position displaying portion in conjunction with each other. 
         FIG. 18  is a view illustrating another configuration of the observation position displaying portion in the operation screen according to the present invention. 
         FIG. 19  illustrates another example of an indicator of the observation position in the observation position displaying portion according to the present invention. 
         FIG. 20  illustrates an example of displaying a positional relationship between detectors in a sample chamber on the observation position displaying portion according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, examples of the present invention will be described with reference to the accommodating figures. The accompanying figures illustrate specific examples in accordance with a principle of the present invention; however, the examples are described for easy understanding of the present invention and are never used to limit the present invention to the description. 
     A charged particle beam apparatus accelerates particles which are charged (charged particles), such as an electron or a cation, with an electric field and irradiates a sample. The charged particle beam apparatus performs observation, analysis, processing, or the like of a sample by using an interaction between a sample and charged particles. Examples to be described below can be applied to an electron microscope, an electron beam drawing apparatus, an ion processing apparatus, an ion microscope, or various charged particle beam apparatuses such as observation·inspection apparatus obtained by applying the apparatuses described above. 
     First Example 
       FIG. 1  is an example of a charged particle beam apparatus. For example, the charged particle beam apparatus includes a sample chamber  101  that maintains a vacuum state such that a charged particle beam is not scattered, an optical system  102  that finally converges charged particle beams to a sample  103 , a detector  106  that detects a signal which is obtained from the sample  103 , and an imaging device  110  that converts the signal detected by the detector  106  into an image. 
     The optical system  102  includes a charged particle source  141 , a deflector  108 , an objective lens  142 , and the like. The optical system  102  may include another lens and an electrode, in addition to the constituent elements described above, some of the elements may be different, and a configuration of the optical system  102  is not limited thereto. 
     The imaging device  110  includes a memory  151  that stores a signal detected in the detector  106 . The imaging device  110  converts the signal detected in the detector  106  into an image. The image acquired by the imaging device  110  is transmitted to control and calculation unit  111  and is displayed on a display unit  112 . 
     The control and calculation unit  111  is a controller that controls various constituent elements of the charged particle beam apparatus in an observation condition input by a user and controls a display of observation results. The control and calculation unit  111  is configured of an information processing device such as a computer. For example, the control and calculation unit  111  includes a CPU (also referred to as a processor)  113 , a main storage device  114  as a memory, a secondary storage device  115  as a HDD, an input unit  116  as a keyboard and a mouse, the display unit  112  as a display, and a communication unit (not illustrated) that communicates with constituent elements of the charged particle beam apparatus. 
     The control and calculation unit  111  is capable of displaying, on the display unit  112 , an image from the imaging device  110  and information of an observation position from a stage control device  120  into a type that is viewed by a user and storing the image and the information in the storage devices  114  and  115 . In order to perform such a process, the control and calculation unit  111  includes a display processing unit  117  that performs a process of displaying an operation screen on the display unit  112  and a setting processing unit  118  that sets various observation conditions. 
     The process that is executed by the control and calculation unit  111  can be executed by software. For example, various programs stored in the secondary storage device  115  is evolved in the main storage device  114 . Here, programs corresponding to the display processing unit  117  and the setting processing unit  118  are evolved. In addition, an image input from the imaging device  110  is temporarily stored in the main storage device  114 . The CPU  113  executes a program loaded in the main storage device  114 . 
     The charged particle beam apparatus includes a sample stage  104  on which the sample  103  is mounted, a stage  105  on which the sample stage  104  is disposed, and a deflector  108  that changes an irradiation position of the charged particle beam so as to change the observation position. The charged particle beam apparatus may include at least one of the stage  105  and the deflector  108 , as a mechanism that changes the observation position. 
     The stage  105  is a mechanism that moves the sample stage  104  so as to change the observation position. The stage  105  is controlled by the stage control device  120 . The stage control device  120  includes a controller  121 , a drive unit  122 , and a coordinate storage unit  123 . The controller  121  controls an operation of the entire stage control device  120 . The drive unit  122  generates a drive signal and drives the stage  105 . The coordinate storage unit  123  stores a stage coordinate. The controller  121  acquires stage coordinate information from the coordinate storage unit  123  and transmits the stage coordinate image to the control and calculation unit  111 . In this manner, the control and calculation unit  111  is capable of finding the coordinate position of the captured image. The stage coordinate may be stored in the stage control device  120  or may be stored in the control and calculation unit  111 . 
     The deflector  108  is controlled by the deflection control device  130 . The deflection control device  130  includes a controller  131 , a drive unit  132 , and a coordinate storage unit  133 . The controller  131  controls an operation of the entire deflection control device  130 . The drive unit  132  generates a drive signal and drives the deflector  108 . The coordinate storage unit  133  stores a deflection degree. The controller  131  acquires the deflection degree information from the coordinate storage unit  133  and transmits the information to the control and calculation unit  111 . In this manner, the control and calculation unit  111  is capable of finding whether any coordinate on the sample  103  is irradiated with the charged particle beam. The deflection degree may be stored in the deflection control device  130  or may be stored in the control and calculation unit  111 . According to the configuration, it is possible to identify the acquired image and observation position. 
       FIGS. 2 and 3  illustrate an example of the operation screen that is displayed on the display unit  112 . The display processing unit  117  of the control and calculation unit  111  displays the operation screen on the display unit  112 . Hereinafter, an image that is obtained by irradiating the sample  103  with the charged particle beam is referred to as an “observation image”, and an image for identifying the observation position in the sample  103  is referred to as an “observation position displaying image”. In this example, the operation screen includes an observation image displaying portion  201 , an observation image importing portion  202 , an observation position displaying portion  203 , an observation magnification setting portion  205 , and an observation position displaying portion-magnification setting portion  206 . 
     The observation image displaying portion  201  is a region for displaying the observation image. The observation image that is obtained by irradiating the sample  103  with the charged particle beam is input to the control and calculation unit  111  via the imaging device  110 . The display processing unit  117  displays the observation image on the observation image displaying portion  201 . In an example in  FIG. 2 , an image displayed on the observation image displaying portion  201  is a low-magnification image obtained by capturing the entire sample  103 . 
     The observation position displaying portion  203  is a region for displaying the observation position displaying image. The observation image importing portion  202  is an interface for importing the observation position displaying image on the observation position displaying portion  203 . Here, in order to acquire the observation position displaying image, a user clicks the observation image importing portion  202  by using the input unit  116 . When receiving the input, the display processing unit  117  acquires an image that is displayed on the observation image displaying portion  201 , and the image is displayed on the observation position displaying portion  203 . Here, as illustrated in  FIG. 3 , the observation position displaying image that is displayed on the observation position displaying portion  203  is a first image  204  having a low magnification. 
     The observation magnification setting portion  205  is a slide bar by which a magnification of the observation image is settable. The observation magnification setting portion  205  can increase or decrease the magnification of the observation image.  FIG. 3  illustrates an example in which the user operates the observation magnification setting portion  205  by using the input unit  116  after the first image  204  is displayed on the observation position displaying portion  203 , and the magnification of the observation image is increased. 
     The display processing unit  117  displays an observation position indicator  207  on the observation position displaying portion  203  in order to assist identification of the observation position. In the example in  FIG. 3 , a position of the image that is currently displayed on the observation image displaying portion  201  is displayed on the first image  204  by the observation position indicator  207 . In this example, the observation position indicator  207  is a frame that indicates the same region as an observation field. 
     The observation position displaying portion-magnification setting portion  206  is an interface for adjusting the magnification of the observation position displaying portion  203  and can be used to zoom in to and out from the observation position displaying image. The observation position displaying portion-magnification setting portion  206  can zoom in to or out from the first image  204 . In the related art, in a case where the magnification of the observation image is increased, the indicator of the observation position is reduced on the image having the low magnification, and thus it is difficult to find an observation field range and the observation position. By comparison, in this example, the observation magnification setting portion  205  can increase the magnification of the observation image, a button (plus button) of the observation position displaying portion-magnification setting portion  206  is pressed such that it is possible to zoom in to the observation position displaying image. In association with the operation, the image that is displayed on the observation position displaying portion  203  zooms in and the observation position indicator  207  in a region of the observation field is increased. In this manner, the user can find the observation field range and observation position with accuracy. 
     In this example, the observation position indicator  207  may be a frame that indicates the same region as the observation field or may be a cross cursor. The observation position indicator  207  may be capable of identifying an observation position or may have a different shape. In addition, here, as an example, the observation position indicator  207  is displayed on the observation position displaying portion  203 ; however, the observation position indicator may not be displayed. 
     In the example, the display processing unit  117  displays the first image  204  on the observation position displaying portion  203  such that the central position of the observation image displaying portion  201  is coincident with the central position of the observation position displaying portion  203 . Hence, when the stage  105  or the deflector  108  for changing the observation position is controlled and the observation position is changed, the display processing unit  117  moves the first image  204  in the observation position displaying portion  203  in conjunction with change in observation position. In this example, the display processing unit  117  always displays the current observation position (observation position indicator  207 ) at the central position of observation position displaying portion  203 . As an another example, the first image  204  is not moved, and the observation position indicator  207  may be moved in the observation position displaying portion  203  in conjunction with the control of the stage  105  or the deflector  108 . 
     In addition, in the example, a predetermined position on the first image  204  of the observation position displaying portion  203  is clicked, and thereby the first image can move to the observation position corresponding to the clicked position. When receiving information of a click to the observation position displaying portion  203 , the setting processing unit  118  transmits a control signal to the stage control device  120  or the deflection control device  130 . In this manner, the first image moves to the observation position corresponding to the clicked position. The display processing unit  117  displays the observation image of the observation position obtained after the movement on the observation image displaying portion  201  and the first image  204  is moved such that the clicked position is coincident with the center of the observation position displaying portion  203 .  FIG. 4  illustrates an operation screen obtained after the observation position is designated. The user clicks the position  208  on the operation screen in  FIG. 3 . The setting processing unit  118  transmits the control signal to the stage control device  120  or a deflection control device  130  such that the position  208  is coincident with the observation position. The display processing unit  117  displays the observation image of the observation position on the observation image displaying portion  201  and moves the first image  204  such that the clicked position  208  is coincident with the center of the observation position displaying portion  203 . 
     It is possible to use various designation methods as the designation method described above as long as it is possible to designate the observation position. The designation method of the observation position may be a method by the click or may be a method of moving the first image  204  through drag and drop with respect to the observation position indicator  207 . In addition, in a case of using a touch panel, the designation method described above may be a touch operation, a drag operation, or the like. 
     In addition, the designation of the observation position may be performed on the observation image displaying portion  201 . For example, any position on the observation image displaying portion  201  is clicked. The setting processing unit  118  transmits the control signal to the stage control device  120  or the deflection control device  130  such that the clicked position is coincident with the observation position (that is, the clicked position is coincident with the central position of the observation image displaying portion  201 ). The display processing unit  117  displays the observation image of the observation position on the observation image displaying portion  201  and moves the first image  204  such that the clicked position is coincident with the center of the observation position displaying portion  203 . 
       FIGS. 5 and 6  illustrate an example in which a plurality of images are imported on the observation position displaying portion  203 . In the example, it is possible to import the plurality of images having different magnifications on the observation position displaying portion  203 . For example, in the state in  FIG. 3 , a user clicks the observation image importing portion  202  by using the input unit  116 . At this time, the display processing unit  117  displays a second image  301  having an observation magnification higher than that of the first image  204  on the observation position displaying portion  203 . The second image  301  has a visual field narrower than that of the first image  204 ; however, when the images are compared in the same field region, the second image  301  has higher resolution than the first image  204  and becomes an image having much information. As described above, a high-magnification image is obtained in a region in which the user is interested, and it is possible to import the image as the observation position displaying image. Hence, it is possible to generate an observation position displaying map having a larger amount of information in the region in which the user is interested. 
     The first image  204  and the second image  301  imported by the observation image importing portion  202  are accumulated in the main storage device  114  or a secondary storage device  115  in a form associated with the coordinate positions of the images. The display processing unit  117  superimposes and displays a plurality of observation position displaying images (the first image  204  and the second image  301 ) having different magnifications on the observation position displaying portion  203 , based on the magnification and the coordinate at which the observation images (here, the first image  204  and the second image  301 ) are acquired. 
       FIG. 5  illustrates an example in which the user operates the observation magnification setting portion  205  by using the input unit  116  after the second image  301  is imported on the observation position displaying portion  203 , and the magnification of the observation image is increased. In the example in  FIG. 5 , a position of the observation image that is currently displayed on the observation image displaying portion  201  is displayed on the second image  301  by the observation position indicator  207 . 
       FIG. 6  illustrate an example in which a button (minus button) of the observation position displaying portion-magnification setting portion  206  is pressed and the observation position displaying image (the first image  204  and the second image  301 ) zoom out. The first image  204  and the second image  301  are displayed on a position corresponding to the coordinate position, based on the coordinate position during the imaging. In the example in  FIG. 6 , the first image  204  and the second image  301  are superimposed and displayed on the observation position displaying portion  203 . Since the second image  301  is the high-magnification image, a display size of the second image  301  on the observation position displaying portion  203  is smaller than a display size of the first image  204 . Here, the display processing unit  117  superimposes and displays the second image  301  having the adjusted size at a position (coordinate position) corresponding to the first image  204 . In  FIGS. 5 and 6 , an example in which two images having different magnifications during the observation are imported on the observation position displaying portion  203 ; however, it is needless to say that three or more images may be imported on the observation position displaying portion  203 . 
     According to the configuration described above, while the user appropriately changes the magnification and the observation position of the observation image, it is possible to import the plurality of images having different magnifications as the observation position displaying image on the observation position displaying portion  203 . It is possible to identify the observation position on the image (first image  204 ) having the low magnification in a case where the magnification of the observation image is low, whereas it is possible to identify the observation position on the image (second image  301 ) having the high magnification in a case where the magnification of the observation image is high. 
     In addition, according to the configuration described above, the user can import many images having the high resolution in a region in the vicinity of a structure as an observation object, and thus much information is obtained. On the other hand, in a region in which only an external appearance of the sample  103  is seen, the image having low resolution may be imported. Hence, while the user appropriately changes the magnification and the observation position of the observation image according to an observation object of the user, it is possible to generate a map for identifying the observation position. In addition, since the user may import an image having the high resolution in only a necessary region, it is possible to reduce an amount of use of the image memory. In addition, since an amount of irradiation to the sample  103  with the charged particle beam, it is possible to reduce damage to the sample  103 . 
       FIGS. 7 to 9  illustrate an example in a case of using a rotation operation by the stage and the optical system. The stage  105  has two axes (an X axis and a Y axis) through which movement in a plane is performed to be orthogonal to the charged particle beam and an axis (a Z axis) that moves in a direction (vertical direction) in which the sample  103  is parallel with the charged particle beam. In addition to this, the stage  105  has an axis (T axis) of inclination of the sample  103  with an axis orthogonal to the charged particle beam as the center and an axis (R axis) of rotation of the sample  103  around an axis parallel to the charged particle beam. Here, rotation on the R-axial stage in the stage  105  is described. 
     When the R-axis stage is rotated such that an orientation of the sample  103  is rotated, the observation image that is displayed on the observation image displaying portion  201  is rotated. In conjunction with the rotation, the display processing unit  117  rotates the first image  204  and the second image  301  about a coordinate (reference sign  401 ) of a rotation axis of the R-axis stage on the observation position displaying portion  203 .  FIG. 7  illustrates an operation screen obtained before the rotation operation by the stage or the optical system.  FIG. 8  illustrates an operation screen obtained when the rotation operation is performed by the R-axis stage. 
     In addition, the optical system  102  includes a mechanism that changes a scanning direction of the charged particle beam. Hence, it is possible to change the scanning direction of the charged particle beam and to rotate and display the observation information by the optical system  102 .  FIG. 9  illustrates the operation screen obtained when the rotation operation is performed by the deflector  108  of the optical system  102 . In a case where the optical system  102  rotates the observation image, the display processing unit  117  rotates the first image  204  and the second image  301  about the center (reference sign  402 ) of the observation position displaying portion  203  in conjunction with the rotation of the observation image. 
     As described above, in a case where the display processing unit  117  moves the observation position by the stage  105  or the deflector  108 , the display processing unit  117  moves the first image  204  and the second image  301  in conjunction with the movement of the observation position. 
     According to the configuration described above, an orientation of the images (the first image  204  and the second image  301 ) of the observation position displaying portion  203  is always coincident with that of the observation image displaying portion  201 . Hence, the user can find the orientation of the sample  103  with intuition, and the operability improves. 
       FIG. 10  illustrates an example of the observation position displaying portion  203 . In  FIG. 10 , the same reference signs are assigned to the same constituent elements as those in  FIGS. 2 and 3 , and the description thereof is omitted. 
     In the configuration, a positional relationship between the sample  103  and the sample stage  104  is unclear. In addition, when the observation position displaying image is imported on the observation position displaying portion  203 , the position of the sample  103  in the sample chamber  101  is unclear. Hence, a sample stage simulating  FIG. 501  and the sample chamber cross-section simulating  FIG. 502  are displayed on the observation position displaying portion  203 . In this manner, before the observation position displaying image is imported on the observation position displaying portion  203 , it is possible to substantially find the position of the sample  103  in the sample chamber  101  and a positional relationship between the sample stage  104  and the observation sample. 
     In addition, the display processing unit  117  changes a size of the sample stage simulating  FIG. 501  by linking with a size of the sample stage  104  and displays the figure on the observation position displaying portion  203 . Hence, it is possible to more intuitively find a positional relationship between the sample stage and the sample  103  in the sample chamber  101 . 
     In the example, when the stage control device  120  moves the stage  105 , the display processing unit  117  moves the sample stage simulating  FIG. 501  on the observation position displaying portion  203  in conjunction with the movement of the stage  105 . In this manner, the user can find the positional relationship obtained during the observation in real time. 
     In addition, any position of the observation position displaying portion  203  is clicked, and thereby the stage  105  may be moved to the clicked position. When receiving information of a click to the observation position displaying portion  203 , the setting processing unit  118  transmits a control signal to the stage control device  120 . The sample stage simulating  FIG. 501  of the observation position displaying portion  203  may be moved through drag and drop, and thereby the stage  105  may be moved. The setting processing unit  118  transmits the control signal to the stage control device  120  such that the position of the sample stage simulating  FIG. 501  after the drag and drop is coincident with the position of the stage  105 . According to the configuration described above, it is possible to change the observation field by the click or the drag and drop on the observation position displaying portion  203 . In particular, in a case where many images and various setting portions are displayed on the observation position displaying portion  203 , it is advantageous to be able to designate the observation position by the drag and drop. 
     In addition, the display processing unit  117  displays, on the observation position displaying portion  203 , a center indicator  503  indicating a position that is currently observed. The user can identify the accurate observation position with the center indicator  503 . 
     The display processing unit  117  controls to decrease a size of the observation position indicator  207 , when the magnification of the observation image increases. In addition, the display processing unit  117  controls to increase the size of the observation position indicator  207 , when the magnification of the observation image decreases. 
     The display processing unit  117  controls to increase the size of the observation position indicator  207 , when the magnification of the observation position displaying portion  203  increases by the observation position displaying portion-magnification setting portion  206 . In addition, the display processing unit  117  controls to decrease the size of the observation position indicator  207 , when the magnification of the observation position displaying portion  203  decreases by the observation position displaying portion-magnification setting portion  206 . According to the control described above, it is possible to find a visual field range of the current observation position with accuracy. 
     When the observation position displaying image is imported on the observation position displaying portion  203  by the observation image importing portion  202 , the display processing unit  117  adjusts the magnification of the observation position displaying portion  203  such that the imported observation position displaying image is displayed on the entire region of the observation position displaying portion  203 . In this manner, it is possible to adjust current observation magnification and the magnification of the observation position displaying portion  203  immediately after the image imported. This function makes it possible to find the accurate observation position without manipulating the magnification of the observation position displaying portion  203 . In addition, the adjustment of the magnification of the observation position displaying portion  203  enables the user to immediately find which position on the sample  103  is observed. 
     In addition, in a case where the magnification of the observation position displaying portion  203  decreases, and an image is acquired in a condition of the high observation magnification, the image is displayed to have a small size in the observation position displaying portion  203 , and thus visibility deteriorates. Hence, when the magnification of the observation position displaying portion  203  decreases, the display processing unit  117  may display the image in a rectangular frame having the same size as that of the image. In a case where only the position of the imported image needs to be found, a mark is not limited to the frame, and a mark such as a point or a circle may be displayed at the position of the image. 
     In addition, when the magnification of the observation position displaying portion  203  decreases, the display processing unit  117  may set the image to non-display in a case where the observation position displaying image is smaller than a predetermined size. For example, a first image  511  and a second image  512  are displayed on the observation position displaying portion  203 . Here, the first image  511  is a high-magnification image obtained when the observation is performed at high magnification, and the second image  512  is a low-magnification image obtained when the observation is performed at magnification lower than that of the first image  511 . When the magnification of the observation position displaying portion  203  decreases, the display processing unit  117  sets the first image  511  to non-display in a case where the first image  511  is smaller than the predetermined size. On the other hand, when the magnification of the observation position displaying portion  203  increases, the display processing unit  117  redisplays the first image  511 . 
     The observation image importing portion  202  may be a button as illustrated in  FIG. 10  or may be realized in another form. For example, the observation image importing portion  202  may be realized as a mouse gesture or another interface such as a gesture performed by a function of a touch monitor. In addition, as another example, the display processing unit  117  may import the observation image as the observation position displaying image on the observation position displaying portion  203 , in conjunction with an operation of capturing the observation image or stopping the display of the observation image. In addition, as still another example, the observation image may be automatically imported as the observation position displaying image on the observation position displaying portion  203  in an observation condition designated by a user in advance. 
     The display processing unit  117  may manage history of importation performed by the observation image importing portion  202 . For example, the display processing unit  117  may manage history of coordinates at which the observation position displaying image is imported and may display the history on the operation screen. The user can designate a coordinate at which the observation position displaying image was imported in the past from the history. When the coordinate is designated, the setting processing unit  118  controls to move the observation position to the designated coordinate. In this manner, it is possible to cause the position at which the observation position displaying image is imported, to reappear, and it is possible to easily reimage an observation position displaying image. 
     The display processing unit  117  performs calculation such that the first image  511  has the same magnification as that of the second image  512  and displays the first image  511  and the second image  512  obtained after the calculation on the observation position displaying portion  203 . Hence, as illustrated in  FIG. 10 , since the first image  511  is an image acquired at the magnification higher than that of the second image  512 , a display size of the first image  511  is smaller than a display size of the second image  512  on the observation position displaying portion  203 . 
     As described above, the observation image importing portion  202  has a function of storing an observation image at any position as the observation position displaying image; however, the observation image importing portion is not limited thereto. The control and calculation unit  111  may repeat the stage control or the image storage such that observation images of the entire region of the sample stage  104  are acquired and, then, may acquire the observation position displaying image. In the example in  FIG. 10 , the observation position displaying portion  203  includes a continuous image importing portion  504 . The user clicks the continuous image importing portion  504  by using the input unit  116 . When the control and calculation unit  111  receives the input, the setting processing unit  118  controls the stage  105  or the deflector  108  such that the entire region of the sample stage  104  is imaged. The display processing unit  117  arranges a plurality of captured images on the observation position displaying portion  203  depending on coordinates of positions of the images. In this manner, it is possible to automatically acquire a wide region image having the low magnification. The user can designate a region in which the user is interested while watching the wide region image, import a high magnification image of the region on the observation position displaying portion  203 , and generate a map on which the high magnification image is superimposed on the low magnification wide region image. The continuous image importation may be continuously performed at preset magnification so as to import the images, and the images of the entire region of the sample captured at the magnification, at which the observation is currently performed, may be imported. 
     In addition, in a case where the observation image is positioned based on only the stage coordinate, and the charged particle beam is deflected such that the visual field is moved, a stage coordinate position and the observation position on the sample  103  are likely to be shifted from each other. In order to solve such a problem, in the example in  FIG. 10 , the observation position displaying portion  203  includes a deflection degree displaying indicator  505  and a deflection cancelling function  506 . 
     In a case where visual field movement is performed by deflecting the charged particle beam by the deflector  108 , the display processing unit  117  moves the vertical axis and the horizontal axis of the cross-shaped deflection degree displaying indicator  505  so as to correspond to the visual field movement due to the deflection.  FIG. 11  is a diagram illustrating an operation of the deflection degree displaying indicator  505 . The display processing unit  117  moves the vertical axis and the horizontal axis of the deflection degree displaying indicator  505  depending on a deflection degree. In this manner, it is possible to show the user how much the stage position and the observation position are shifted from each other during the observation. The deflection degree displaying indicator  505  does not need to have the cross shape and may have another shape of a circle or a point. The deflection degree displaying indicator  505  may have any shape as long as a direction and a size from a reference position can be known. 
     In the example in  FIG. 10 , the deflection cancelling function  506  functions both as a frame indicating the deflection degree displaying indicator  505  and as a button for canceling the deflection of the charged particle beam. In a case where the user does not want the shift between the stage position and the observation position due to the deflection, the user clicks the deflection cancelling function  506  by using the input unit  116 . When the setting processing unit  118  receives the input, the setting processing unit transmits a control signal to the deflection control device  130  such that the deflection is canceled. In this manner, the deflection degree is eliminated, the stage coordinate position is coincident with the observation position, and thereby it is possible to reduce a positional shift of the imported image. 
     In the example, the observation position displaying image is disposed on the observation position displaying portion  203  based on only the stage coordinate; however, this is not limited thereto. The control and calculation unit  111  may import the observation position displaying image on the observation position displaying portion  203  in a coordinate system obtained in consideration of the deflection degree. In a case of such a configuration, a function related to the deflection described above may also be omitted. 
     In addition, the observation position displaying portion  203  includes a movable range frame  507 . The movable range frame  507  represents a movable limit of the stage  105  in the example. In a case where an outer side of a movable range of the stage is designated as a moving destination, a method of displaying a message showing that the stage is present out of the moving range is well known. In the example in  FIG. 10 , when the drag and drop of the sample stage simulating  FIG. 501  for moving the stage is performed, restriction is imposed such that the sample stage simulating  FIG. 501  is not able to move to the outer side of the movable range frame  507 . In other words, the display processing unit  117  performs control such that the sample stage simulating  FIG. 501  is movable within the movable range frame  507 . In this manner, an unnecessary operation or displaying an error message is omitted, and thus it is possible to reduce time and effort of the user. It is needless to say that the display processing unit  117  may display a warning message on the operation screen at a timing of dropping, without the restriction description. 
     As described above, it is possible to change the magnification of the observation position displaying portion  203  by using the observation position displaying portion-magnification setting portion  206 . For example, in a case where the observation position is identified by further increasing the magnification, the observation position displaying portion-magnification setting portion  206  zooms in to the observation position displaying image. At this time, a display size of the observation position indicator  207  also increases. The change in magnification of the observation position displaying portion  203  may not be limited to performance of a configuration of the observation position displaying portion-magnification setting portion  206 . The magnification change of the observation position displaying portion  203  may be performed via a mouse wheel, a mouse gesture, or another interface such as a gesture performed by a function of a touch monitor. 
     In the example in  FIG. 10 , it is possible to record the coordinate of the observation position. Therefore, the observation position displaying portion  203  includes a coordinate registering portion  508 . The user clicks the coordinate registering portion  508  by using the input unit  116 . When the display processing unit  117  receives the input, the display processing unit stores information in association with the observation image with the coordinate of the observation position to the main storage device  114  or the secondary storage device  115 . Here, a registered coordinate is a coordinate of the center of the observation field. In addition, the display processing unit  117  may display a mark of a registration position on the observation position displaying portion  203 . In this case, when the observation position is moved, the display processing unit  117  moves the observation position displaying image and the mark in a state in which the positional relationship therebetween is maintained. The setting of the observation image and the coordinate of the observation position may be recorded in association with a set identifier to the main storage device  114  or the secondary storage device  115 . A window for designating the coordinate of the observation position may be displayed on the operation screen. In this case, when the user designates an identifier of the coordinate, the observation field is moved to an observation position corresponding to the identifier. As another example, when the mark of the observation position displaying portion  203  is clicked, the observation field may be moved to a coordinate position corresponding to the mark. 
     When the magnification of the observation position displaying portion  203  is set to the high magnification, the magnification of the observation position displaying portion  203  is set to the low magnification in some cases, in order to find which portion on the entire sample  103  is viewed. In this case, in order to decrease the magnification to the extent that the entire sample  103  is displayed on the observation position displaying portion  203 , it is necessary to click the observation position displaying portion-magnification setting portion  206  several times. The user needs to spend time and effort for this operation. Therefore, in the example in  FIG. 10 , the observation position displaying portion  203  includes a magnification changing portion  509  for changing the magnification to a prescribed magnification. The user clicks the magnification changing portion  509  by using the input unit  116 . When the display processing unit  117  receives the input, the display processing unit switches the magnification to the prescribed magnification designated by the user. For example, the magnification at which the entire region of the sample is displayed is set as the prescribed magnification in advance. In this manner, by clicking the magnification changing portion  509  only once, it is possible to immediately check which portion on the sample  103  is observed during the observation. Hence, the usability improves. 
     The observation position displaying portion  203  may have a function of setting the prescribed magnification of the magnification changing portion  509  while the user checks the observation position displaying portion  203 . For example, a configuration may be employed such that the user can zooms in to or out from the observation position displaying portion  203  by using the observation position displaying portion-magnification setting portion  206  and can designate the magnification as the prescribed magnification of the magnification changing portion  509  by using any designating method (for example, setting by right clicking) when reaching desired magnification. 
     In addition, the observation position displaying portion  203  includes a stage rotation angle indicator  510 . The stage rotation angle indicator  510  indicates a rotation angle obtained when an R-axis stage is rotated such that an orientation of the sample  103  is rotated. The display processing unit  117  rotates the stage rotation angle indicator  510  around the center of the observation position displaying portion  203  depending on the rotation of the R-axis stage. In this manner, the user can easily find the rotation angle of the R-axis stage. 
     As illustrated in  FIG. 10 , the first image  511  and the second image  512  are superimposed on each other in some cases. In such a case, a front/back relationship of the first image  511  and the second image  512  may be switched depending on necessary information. For example, in  FIG. 10 , the first image  511  having the high magnification is displayed in front of the second image  512  having the low magnification. In this manner, since the image (first image  511  having the high magnification) with more information is displayed in front the observation position displaying portion  203  even when the images have the same visual field, an amount of information for identifying the observation position increases whenever an image is imported and superimposed on the observation position displaying portion  203 . The front/back relationship of the images may be changed by a condition. For example, in a case of the sample  103  that is changed with time, the display processing unit  117  may display the latest captured image in front. In this manner, it is possible to identify the observation position from an image showing a state close to the current state of the sample  103  during the observation. 
     In addition, depending on an observation condition of the charged particle beam apparatus such as a degree of vacuum, an acceleration voltage, and a beam diameter on the sample, the display processing unit  117  may control the front/back relationship of a plurality of images. For example, in a case where the degree of vacuum is low, an electron beam is scattered in general, and an image having poor visibility is acquired. The display processing unit  117  acquires information of the degree of vacuum as an observation condition. The display processing unit  117  may display an image on the observation position displaying portion  203 , which is imported when the degree of vacuum is high, in front of an image imported when the degree of vacuum is low. 
     As another example, the display processing unit  117  may preferentially display an image on the observation position displaying portion  203 , which is imported when the acceleration voltage is high, in front. In this case, the user can preferentially see the image having high resolution. On the other hand, the display processing unit  117  may preferentially display an image on the observation position displaying portion  203 , which is imported when the acceleration voltage is low, in front. In this case, the user can preferentially see the information on a front surface of the sample. 
     It is also possible to expect the same effects about the beam diameter on the sample. In a case where the user wants to preferentially display the image having the high resolution even the image has much noise, the display processing unit  117  may preferentially display an image on the observation position displaying portion  203 , which is imported when the beam diameter on the sample is small, in front. On the other hand, in a case where the user wants to preferentially display an image that has less noise and is easier to be seen, the display processing unit  117  may preferentially display an image on the observation position displaying portion  203 , which is imported when the beam diameter on the sample is large, in front. 
     The charged particle beam apparatus may include a plurality of detectors not illustrated in  FIG. 1 . In this case, observation images are acquired while the plurality of detectors are switched. Since the observation position displaying image is not limited to a signal of a specific detector, images acquired by a plurality of types of detectors are simultaneously arranged on the observation position displaying portion  203  in some cases. When the types of detectors are different, appearances are significantly different from each other in some cases even when the same sample is detected. In this case, the observation position displaying image does not correspond to the observation image in some cases. In order to solve such a problem, the display processing unit  117  may preferentially display an image on the observation position displaying portion  203 , which is acquired by a currently selected detector, in front. In this manner, the observation image and the image on the observation position displaying portion  203  look alike and can show the accurate observation position. 
     The control of the front/back relationship of the image described above may be automatically switched by the control and calculation unit  111  depending on an observation object and a purpose of the apparatus or may be selected by the user. 
     In addition, a display method of the images on the observation position displaying portion  203  is not limited to the simple superimposition of the images. For example, the display processing unit  117  may cause a transmission type image to be displayed in front of the plurality of images. According to this method, the user can see information of the images on the back side, and it is possible to show the user more information. 
     In addition, the display processing unit  117  may add pseudo colors to the plurality of images. For example, in a case of images of signals from which composition information is obtained, the display processing unit  117  may add pseudo colors to the images depending on composition and may superimpose the images on the observation position displaying portion  203 . In this manner, the user can find not only information of a shape but also a difference in composition at a glance, and thus it is possible to show the user more information. 
     In addition, in a case where the charged particle beam apparatus includes the plurality of detectors, the display processing unit  117  may add different pseudo colors to the images that are obtained in response to signals from different detectors. The display processing unit  117  may superimpose and display the images. 
     In addition, in a case of images of signals that include much edge information, the display processing unit  117  may generate images obtained by picking out only edge portions and may superimpose the plurality of images, in which the edge is highlighted, on the observation position displaying portion  203 . In this manner, the visibility in the image improves. 
     In the configurations described above, the images captured by the charged particle beam apparatus are described; however, an image used for an observation position display is not limit to an image obtained by the charged particle beam apparatus and may be an image of an observation sample like an image obtained from a camera, an optical microscope, a fluorescence microscope, a laser microscope, or X-rays. In addition, not only the captured image but also a design drawing such as a CAD drawing may be used as the observation position display. 
       FIG. 12  illustrates an example in which an image captured by an optical camera is displayed on the observation position displaying portion  203 . For example, an optical camera  143  is mounted in an upper side of the sample chamber  101  (refer to  FIG. 1 ). The display processing unit  117  acquires an optical image  601  captured by the optical camera  143  and displays the optical image  601  on the observation position displaying portion  203 . The image that is displayed on the observation position displaying portion  203  is not limited to an image captured by the camera and may be any image related to the sample  103 . For example, the display processing unit  117  may display, on the observation position displaying portion  203 , both or by switching a drawing showing a shape of the sample or an image of a type of signal different from a signal used for the observation and or to another image. 
     In the example in  FIG. 12 , the display processing unit  117  trims the optical image  601  on the bases of the shape of the sample stage  104  and displays the optical image  601  on the observation position displaying portion  203 . According to the configuration, it is possible to remove unnecessary information on an outer side from the outline of the sample stage  104  and to show the user an observation position in a state in which the sample is close to the real sample. The optical image  601  may be superimposed on the sample stage simulating  FIG. 501  in  FIG. 10 . In addition, as another example, the sample stage simulating  FIG. 501  may be replaced with the optical image  601 . 
     In this manner, before the observation is performed by the charged particle beam apparatus, the user can find substantial information of the entire sample. The user can designate a region in which the user is interested while watching the optical image  601  of the entire sample and import an observation images of the region on the observation position displaying portion  203 . In this manner, it is possible to generate a map on which the observation image is superimposed on the optical image  601 . 
     When a color image like an optical image is imported on the observation position displaying portion  203  and digitally zooms in, a problem arises in that not only the image is blurred but also colors are blurred. Therefore, when the magnification of the observation position displaying portion  203  exceeds a threshold value, the display processing unit  117  may replace a color image with a grayscale image. In this manner, it is possible to perform the zoom-in display without deterioration of the visibility. 
       FIGS. 13 to 15  illustrate a first example of controlling the magnification of the observation image and the magnification of the observation position displaying portion  203  in conjunction with each other. The operation screen includes a magnification conjunction function executing portion  701 . The magnification conjunction function executing portion  701  is used to match the magnification of the observation image on the observation image displaying portion  201  and the magnification of the observation position displaying portion  203 . In the state in  FIG. 13 , the user clicks the magnification conjunction function executing portion  701  by using the input unit  116 . When the setting processing unit  118  receives the input, the setting processing unit controls the constituent elements of the charged particle beam apparatus such that the magnification of the observation image matches the magnification of the observation position displaying portion  203 . The display processing unit  117  displays the observation image obtained after the magnification correction on the observation image displaying portion  201  ( FIG. 14 ). According to the function, it is possible to reduce damage to the sample during the search for the observation position. In addition, after the observation position is substantially determined in the state in  FIG. 14 , the user can designate a detailed observation position as illustrated in  FIG. 15 . 
       FIGS. 16 and 17  illustrate a second example of controlling of the magnification of the observation image and the magnification of the observation position displaying portion  203  in conjunction with each other.  FIG. 17  illustrates a state in which the magnification of the observation image is increased from the state in  FIG. 16 . The display processing unit  117  performs control such that the magnification of the observation image and the magnification of the observation position displaying portion  203  are relatively constant. In the example, regardless of the magnification of the observation image displaying portion  201 , the observation position indicator  207  is displayed to have a constant display size. In a state in which the magnification of the observation position displaying portion  203  is slightly lower than the magnification of the observation image on the observation image displaying portion  201 , the display processing unit  117  displays the observation position displaying image. According to the configuration, there is no need to adjust the magnification of the observation position displaying portion  203 , and thus it is possible to simplify the operation performed by the user. The operation screen includes a magnification conjunction function executing portion  801  on which it is possible to switch the control described above to enablement/disablement. On the magnification conjunction function executing portion  801 , it is possible to switch the control to the enablement/disablement; however, the control described above may be always enable. 
       FIG. 18  illustrates the observation position displaying portion  203  having a configuration that is further increased from the configuration in  FIG. 10 . The observation position displaying portion  203  includes an observation image non-displaying function  901  and a Z-direction image switching function  902 . The observation image non-displaying function  901  is a function of switching the charged particle beam irradiation to the sample  103  to enablement/disablement. The user clicks the magnification conjunction function executing portion  701  by using the input unit  116 . When the setting processing unit  118  receives the input, the setting processing unit controls the irradiation with the charged particle beam. For example, voltage application to the charged particle source (for example, an electron gun) may be stopped or control the deflector  108  such that the sample  103  is not irradiated with the charged particle beam. For example, when a state of irradiation with the charged particle beam is maintained when the observation position is positioned, damage to the sample increases. Hence, the user may cause the observation image non-displaying function  901  to be enable. In this case, the observation image is not displayed on the observation image displaying portion  201 , but only the observation position displaying portion  203  is displayed. In this manner, it is possible to move to the observation position without unnecessary damage to the sample. In particular, the configuration is particularly effective to an apparatus using a beam having a large influence on the sample, such as a focused ion beam. 
     In addition, the Z-direction image switching function  902  is a function of hierarchizing the observation position displaying portion  203  and switching display for each hierarchy. For example, the observation position displaying image may be imported for each acceleration voltage and a plurality of observation position displaying images may be hierarchized to be accumulated in the main storage device  114  or the secondary storage device  115 . The display processing unit  117  displays the plurality of hierarchized observation position displaying images depending on an operation of a button of the Z-direction image switching function  902 . For example, when an upward button of the Z-direction image switching function  902  is clicked, the display processing unit  117  displays the observation position displaying image at one hierarchy above. According to the configuration, it is possible to switch information to information of the surface of the sample and information of the inside of the sample. In addition, in a case where the observation is performed while the surface is scraped through cutting the sample by the focused ion beam or a diamond knife, the observation position displaying images are acquired before the sample  103  is processed, and the images are hierarchized and stored. According to the configuration, while the sample  103  is processed, it is possible to check the structure, which has already been eliminated, again on the observation position displaying portion  203 . 
     The display processing unit  117  may switch the display and the non-display of the observation position displaying image depending on the observation condition (a value of the acceleration voltage, the degree of vacuum, a detector, or the like). In this case, the observation position displaying image may be accumulated in the main storage device  114  or the secondary storage device  115  in association with the observation condition. In addition, the observation position displaying portion  203  may include an input form for designating the observation condition. 
     The observation position displaying image and the coordinate information of the observation position displaying portion  203  described in  FIGS. 2 to 18  can be reproduced without using the charged particle beam apparatus after the observation is performed by the apparatus. For example, the observation position displaying image and the coordinate information accumulated in the secondary storage device  115  may be referred to by an apparatus other than the charged particle beam apparatus. In this manner, in a case where a user wants to perform the observation again later, there is no need to use the charged particle beam apparatus and it is possible to perform the observation by the charged particle beam apparatus in a pseudo manner. 
     The observation position indicator  207  described in FIGS. to  18  is disposed at a position fixed on the observation position displaying portion  203 ; however, the indicator is not limited the configuration.  FIG. 19  illustrates another configuration of the observation position indicator  207 . As illustrated in  FIG. 19 , the display processing unit  117  may move the observation position indicator  207  to a corresponding observation position in association with the movement of the observation position. A relationship between the magnifications and the coordinates of the observation image displaying portion  201  and the observation position displaying portion  203  is maintained, the observation position indicator  207  may be displayed in another form. 
     Second Example 
       FIG. 20  illustrates an example in which a positional relationship between a plurality of detectors is displayed on the observation position displaying portion  203 . In the example, the charged particle beam apparatus includes an energy dispersive X-ray spectrometry (EDX) detector, a reflected electron detector, a secondary electron detector, and a camera. A first detector position display  1101 , a second detector position display  1102 , a third detector position display  1103 , and a camera position display  1104  are displayed on the observation position displaying portion  203 . The first detector position display  1101  represents a position of the EDX detector disposed in the sample chamber  101 . The second detector position display  1102  represents a position of the reflected electron detector disposed in the sample chamber  101  and also has a function of switching the signals of the observation images. The third detector position display  1103  represents a position of the secondary electron detector disposed in the sample chamber  101  and also has a function of switching the signals of the observation images. The camera position display  1104  represents a position of the camera for observing the inside of the sample chamber and also has a function of switching a signal to a camera video. 
     For example, when the user clicks the second detector position display  1102  by using the input unit  116 , the display processing unit  117  switches the observation image on the observation image displaying portion  201  to an observation image in response to a signal from the reflected electron detector. On the other hand, when the user clicks the camera position display  1104  by using the input unit  116 , the display processing unit  117  switches the observation image on the observation image displaying portion  201  to an image from the camera. As described above, it is possible to switch the observation image by using marks of the plurality of detectors and the camera in the observation position displaying portion  203 . 
     The display processing unit  117  may display a currently selected detector and an unselected detector in different display forms. For example, the display processing unit  117  may display the currently selected detector and the unselected detector in different colors. In this manner, the user can find which detector outputs a detection signal in response to which the current observation image is obtained. 
     The image from the camera for observing the inside of the sample chamber may be displayed on the observation image displaying portion  201  or may be displayed as an assisting function on the observation position displaying portion  203 . 
     The display processing unit  117  may display a message when the marks of the plurality of detectors and the camera in the observation position displaying portion  203  are clicked depending on the observation condition. For example, the detectors may include a detector that is not able to be used in a condition. For example, the secondary electron detector in the electron microscope is not able to be used in low vacuum. In a case where the inside of the sample chamber  101  is in low vacuum and the user clicks the third detector position display  1103  by using the input unit  116 , the display processing unit  117  displays a state displaying portion  1105 . A message such as “not usable in low vacuum” is displayed on the state displaying portion  1105 . In this manner, when the user tries to select a detector, it is possible to show reasons why the detector cannot be used. A user who is not familiar with the apparatus can easily understand the state of the apparatus or the like. 
     The display processing unit  117  may display a currently selectable detector and a detector that is not currently selectable under the observation condition in different display forms. For example, the display processing unit  117  may display the currently selectable detector and the detector that is not currently selectable under the observation condition in different colors. 
     The first detector position display  1101 , the second detector position display  1102 , the third detector position display  1103 , and the camera position display  1104  may be controlled so as to always maintain a relationship with the observation position displaying portion  203 . For example, in a case where the R-axis stage is rotated, the display processing unit  117  rotates the first image  511  and the second image  512  and the stage rotation angle indicator  510 ; however, the position displays  1101  to  1104  are not rotated. 
     On the other hand, in a case of a scanning type charged particle beam apparatus, a scanning direction is controlled, and thereby it is possible to rotate the observation image. In this case, the display processing unit  117  rotates all of the first image  511 , the second image  512 , the stage rotation angle indicator  510 , and the position displays  1101  to  1104  depending on the control in the scanning direction. 
     Hereinafter, effects of the examples described above will be described. In the related art, a method for providing the one low-magnification image or the observation position on the connected low-magnification image is used; however, it is difficult to identify the observation position in a case where the magnification of the visual field on the screen of the low-magnification image or the connected image significantly differs from the magnification of the observation field in which observation is currently performed in such a method. In addition, even in a method for providing an observation position by switching a plurality of low-magnification images, an image for displaying observation position is not suitable for the magnification at which the image is currently observed in some cases. 
     In this respect, the charged particle beam apparatus including the observation assisting function of the example described above includes the optical system  102  that irradiates the observation sample with the charged particle beam generated from the charged particle source, the sample stage  104  on which the sample  103  is mounted, the stage  105  that moves the sample stage and the deflector  108  that changes the charged particle beam irradiation position, the detector  106  that detects a signal that is generated from the sample  103  by irradiation with the charged particle beam, and the imaging device  110  that converts the signal acquired by the detector  106  into an image. The plurality of observation position displaying images having different magnifications are displayed on the observation position displaying portion  203  which can zoom in and out, based on an apparatus coordinate system during the capturing. In this manner, it is possible to display the low-magnification image and the high-magnification image on the observation position displaying portion  203 . In addition, it is possible to check the observation position by zooming in to and out from the observation position displaying portion  203 . In this manner, it is possible to provide the observation position even when the magnification at which the current observation is performed (magnification of the observation image) is significantly different from the magnification of the image that displays the observation position, and it is possible to show the user the position at which the current observation is performed, regardless of the magnification of the observation. 
     In addition, in a method in which an observation position is provided on a connected image of the continuous images of a region, since the sample is irradiated with the charged particle beam in relation to regions, a problem arises in that damage to the sample increases, and further a problem arises in that a throughput is degraded in order to capture the plurality of unnecessary images. In this respect, according to the example, since the minimum necessary number of images required to provide the observation position may be acquired, it is possible to reduce the damage to the sample. In addition, since the minimum necessary number of images may be acquired, the throughput in the observation improves. 
     The example described above has the following additional characteristics. The display processing unit  117  may move a display position of the observation position displaying image on the observation position displaying portion  203 , in conjunction with the movement by the stage  105  or the movement of the irradiation position of the charged particle beam by the deflector  108 . In this manner, the user can check the change in irradiation position on the observation position displaying portion  203  in real time. 
     In addition, the observation position displaying portion  203  can receives visual field movement designation by the user. When the setting processing unit  118  receives the visual field movement designation, the setting processing unit controls the stage  105  or the deflector  108  such that the visual field is moved to the designated visual field. In this manner, it is possible to change the observation field on the observation position displaying portion  203 , and thus the operability improves. 
     In addition, the stage  105  includes the R-axis stage. When the sample stage  104  rotates by the R-axis stage, the display processing unit  117  rotates the observation position displaying image with reference to a rotation center position of the R-axis stage on the observation position displaying portion  203 . In this manner, the observation position displaying image rotates similarly to the real observation image, and thereby it is easy for the user to identify the observation position on the observation position displaying portion  203 . 
     In addition, in the charged particle beam apparatus, the optical system  102  has a function of changing a scanning direction of the charged particle beam and rotating the image. When the scanning direction of the charged particle beam is changed, the display processing unit  117  rotates the observation position displaying image on the observation position displaying portion  203  around the observation position. In this manner, the observation position displaying image rotates similarly to the real observation image, and thereby it is easy for the user to identify the observation position on the observation position displaying portion  203 . 
     In addition, the display processing unit  117  displays the sample stage simulating  FIG. 501  that simulates the sample stage  104  on the observation position displaying portion  203 . The display processing unit  117  superimposes and displays the observation position displaying images on the sample stage simulating  FIG. 501  on the observation position displaying portion  203 . In this manner, the user can find a state of the inside of the sample chamber  101  with intuition. 
     In addition, the display processing unit  117  displays the sample chamber cross-section simulating  FIG. 502  that simulates the cross section of the sample chamber on the observation position displaying portion  203 . The display processing unit  117  superimposes and displays the sample stage simulating  FIG. 501 , the sample chamber cross-section simulating  FIG. 502 , and the observation position displaying images on the observation position displaying portion  203 . In this manner, it is possible to intuitively show the user the position and the direction of the sample in the sample chamber  101 . 
     In addition, the display processing unit  117  displays, on the observation position displaying portion  203 , the observation position indicator  207  representing the observation position. The observation position indicator  207  zooms in/out depending on the magnification of the observation of the apparatus and the magnification of the observation position displaying portion  203 . In this manner, the user can check the observation field with a desired size. 
     In addition, the observation position displaying portion  203  includes the observation image importing portion  202  on which the user maintains an observation image at will. Hence, the user can maintain the necessary minimum number of observation position displaying images. In particular, in the related art, as the observation position displaying image, one low-magnification image is acquired in advance or a plurality of low-magnification images are automatically acquired in a process, and thus it is not possible to acquire the appropriate observation position displaying image. In this respect, in the example, the user can acquire the observation position displaying image at the desired magnification and position and can generate the observation position displaying map having a larger amount of information in the region in which the user is interested. 
     In addition, the observation position displaying portion  203  includes the continuous image importing portion  504 . When the continuous image importing portion  504  receives an input, the setting processing unit  118  controls the stage  105  or the deflector  108  such that the entire region of the sample stage  104  is imaged. The display processing unit  117  arranges the plurality of captured images on the observation position displaying portion  203  depending on coordinates of positions of the images. In this manner, in a case where the images of the entire region of the sample stage  104  are acquired as the observation position displaying images, the user can acquire the images automatically and the user can reduce the time and effort. 
     In addition, the charged particle beam apparatus includes an imaging system other than the charged particle beam imaging system that is used during the observation. In the examples described above, the optical camera  143  is used as the imaging system; however, another imaging system may be used. The display processing unit  117  may display, on the observation position displaying portion  203 , both or by switching the drawing showing the shape of the sample or an image of a type of signal different from the signal used during the observation and or to another image. The display processing unit  117  may perform display by removing unnecessary information on the outer side from the outline of the sample stage  104  related to the image captured by the imaging system other than a charged particle beam imaging system. For example, the display processing unit  117  may cut out portions of the sample stage  104  and may display the rest of the sample stage  104  on the observation position displaying portion  203 , in relation to the image captured by the imaging system other than a charged particle beam imaging system. For example, the display processing unit  117  superimposes and displays the image captured by the imaging system other than the charged particle beam imaging system on the sample stage simulating  FIG. 501 ; however, the sample stage simulating  FIG. 501  may be replace and displayed with the image captured by the imaging system other than the charged particle beam imaging system. 
     In addition, the display processing unit  117  may change the sample stage simulating  FIG. 501  or the image captured by the imaging system other than the charged particle beam imaging system depending on the size of the sample stage  104  during the observation. In addition, the display processing unit  117  may change the size that is the reference of the image, on the observation position displaying portion  203 , depending on the size of the sample stage  104  during the observation. 
     In addition, the display processing unit  117  displays an indicator (the deflection degree displaying indicator  505 ) of a deflection degree for moving the visual field during the observation, on the observation position displaying portion  203 . In this manner, the user can always find a difference in stage coordinate. In addition, when the setting processing unit  118  receives an input to the deflection degree displaying indicator  505 , the setting processing unit cancels the deflection by the deflector  108  and the stage coordinate is coincident with the observation position. 
     In addition, in a case where the color image is displayed as the observation position displaying image, the display processing unit  117  may switch and display the color images to the grayscale displays depending on a magnification ratio of the observation position displaying portion  203 . 
     In addition, the observation position displaying portion  203  has a function of designating the observation position by clicking. The display processing unit  117  displays a frame indicating a stage movable range (the movable range frame  507 ) on the observation position displaying portion  203 . When the outer side from the stage movable range is clicked, the display processing unit  117  may display a warning message indicating that the click is out of the stage movement range. In this manner, when the observation position is designated on the observation position displaying portion  203 , it is possible to find a range in which it is possible to designate the observation position. 
     In addition, the observation position displaying portion  203  has a function of designating the observation position by the drag and drop. When the user drag and drops the observation position displaying portion  203 , the display processing unit  117  restricts that the central position of the observation position displaying portion  203  does not move to the outer side of the movable range frame  507 . 
     In addition, the observation position displaying portion  203  includes the coordinate registering portion  508  as the coordinate registering function. When the coordinate registering portion  508  is clicked, the display processing unit  117  may store the coordinate of the observation position designated by the observation position displaying portion  203  and may display the marks indicating the registration position on the observation position displaying portion  203 . The display processing unit  117  moves the mark along with the observation position displaying image, in association with the movement of the observation position. 
     In addition, when the observation position displaying image is imported on the observation position displaying portion  203  by the observation image importing portion  202 , the display processing unit  117  changes the magnification of the observation position displaying portion  203  such that the imported observation position displaying image is displayed on the entire region of the observation position displaying portion  203 . 
     The observation position displaying portion  203  includes the magnification changing portion  509  for immediately setting the magnification of the observation position displaying portion  203  to a predesignated value. The observation position displaying portion  203  may have a function of designating and setting the magnification set in advance while the user checks the observation position displaying portion  203 . 
     In addition, the display processing unit  117  may change the front/back relationship between the plurality of the observation position displaying images which are superimposed and disposed on the observation position displaying portion  203  depending on the designation or the observation condition of the user. For example, the display processing unit  117  may display the observation position displaying image having the high magnification during the observation in front, of the plurality of observation position displaying images. For example, the display processing unit  117  may display the observation position displaying image imported later, in front, of the plurality of observation position displaying images. For example, the display processing unit  117  may display the observation position displaying image selected by a mouse, a keyboard, or a user interface device such as a touch panel, in front. The display processing unit  117  may display the image obtained in response to a specific detection signal in front, of the plurality of observation position displaying images. The display processing unit  117  may switch the front/back relationship of the plurality of observation position displaying images depending on the degree of vacuum during the observation in front. The display processing unit  117  may switch the front/back relationship of the plurality of observation position displaying images depending on the acceleration voltage during the observation. 
     In addition, the display processing unit  117  may add pseudo colors to the signals obtained in response to the images from the different detectors and may superimpose and display the images. 
     In addition, the observation position displaying portion  203  has a function of hierarchizing and displaying the plurality of observation position displaying images. When a button of the Z-direction image switching function  902  is clicked, the display processing unit  117  displays the observation position displaying image for each hierarchy. 
     In addition, the display processing unit  117  may switch the display and the non-display of the images depending on the observation condition (a value of the acceleration voltage, the degree of vacuum, a detector, or the like) in association with the observation position displaying image. 
     In addition, the display processing unit  117  may cause at least one transmission type image of the plurality of observation position displaying images and may superimpose the other images on the observation position displaying portion  203 . 
     In addition, the display processing unit  117  may display the observation position displaying image captured at the high magnification in a frame when the magnification of the observation position displaying portion  203  is lower than that. 
     In addition, the display processing unit  117  may manage, as history, the coordinate at which the observation position displaying image is imported. The observation position displaying portion  203  has a function of designating the coordinate from the history. In this manner, it is possible to cause the position at which the observation position displaying image is imported, to reappear, and it is possible to easily reimage an observation position displaying image. 
     The observation position displaying image and the coordinate information of the observation position displaying portion  203  may be configured to be able to be referred to by another apparatus after the observation by the charged particle beam apparatus is ended. For example, the observation position displaying image and the coordinate information, may be stored in another storage device on the assist storage device or a network. In this manner, it is possible to reproduce the observation position displaying portion  203  without using the charged particle beam apparatus. 
     The observation position displaying portion  203  includes the magnification conjunction function executing portion  701  for matching the magnification of the observation image on the observation image displaying portion  201  and the magnification of the observation position displaying portion  203 . When the magnification conjunction function executing portion  701  is clicked, the setting processing unit  118  sets the magnification of the observation image to the same magnification as that of the observation position displaying portion  203 . 
     The observation position displaying portion  203  includes the observation image non-displaying function  901  for switching the charged particle beam irradiation to the sample to enablement/disablement. When the observation image non-displaying function  901  is clicked, the setting processing unit  118  performs control such that the charged particle beam does not reach the sample  103 . The setting processing unit  118  may stop the voltage application to the charged particle source or control the deflector  108  such that the sample  103  is not irradiated with the charged particle beam. In this manner, it is possible to reduce the damage to the sample. 
     In addition, the display processing unit  117  may be configured to reflect an amount of an image shift to the coordinate of the observation position displaying portion  203 . 
     In addition, in a case where the observation position is changed by the stage  105  or the deflector  108 , the display processing unit  117  may move the marker indicating the observation position on the observation position displaying portion  203  without moving the observation position displaying image. 
     In addition, the display processing unit  117  may embed the mark in the observation position displaying portion  203  and may display information (for example, a coordinate) of a point when the user moves a mouse over the mark. 
     The observation position displaying portion  203  displays the positional relationship between the plurality of detectors in the sample chamber  101  and includes an interface (a figure or a display) that can be used to switch the plurality of detectors. When the interface is clicked, the display processing unit  117  switches the observation image of the observation image displaying portion  201  to the observation image obtained in response to a signal from the clicked detector. 
     The display processing unit  117  may display the currently selected detector and the unselected detector in different display forms. For example, the display processing unit  117  may display the currently selected detector and the unselected detector in different colors. In this manner, the user can intuitively recognize the selected detector. 
     The display processing unit  117  may display the currently selectable detector and the detector that is not currently selectable under the observation condition in different display forms. For example, the display processing unit  117  may display the currently selectable detector and the detector that is not currently selectable under the observation condition in different colors. In this manner, the user can intuitively recognize the detector that cannot be selected. 
     In addition, the display processing unit  117  may switch the display/non-display of the figure or display depending on the positional relationship between the plurality of detectors. In this manner, when unnecessary, the positional relationship between the plurality of detectors can be non-displayed on the observation position displaying portion  203 . 
     The present invention is not limited to the examples described above and includes various modification examples. The examples are described in detail for easy understanding of the present invention, and the present invention is not absolutely limited to inclusion of the entire configuration described above. In addition, it is possible to replace a part of a configuration of a certain example with a configuration of another example. In addition, it is possible to add a configuration of a certain example to a configuration of another example. For example, it is possible to improve the operability by combining the plurality of examples described above. In addition, it is possible to perform addition/removal/replacement of a configuration to/from/with a part of a configuration of each of the examples. 
     In addition, a part or the entirety of the configurations, the functions, the processing units, processing means, or the like may be realized by hardware by designing an integrated circuit, for example. In addition, the configurations, the functions, and the like described above may be realized with software by analyzing and performing programs by which processors realize respective functions. Information of a program, a table, or a file that realizes the functions can be stored in various types of non-transitory computer readable media. For example, a flexible disk, a CD-ROM, DVD-ROM, a hard disk, an optical disk, a magneto-optical disk, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used as the non-transitory computer readable medium. 
     In the examples described above, control wires or information wires are illustrated when the wires are considered to be necessary for description, and all of the control wires or the information wires are not absolutely illustrated for a product. All of the configurations may be connected to each other. 
     REFERENCE SIGNS LIST 
     
         
         
           
               101 : sample chamber 
               102 : optical system 
               103 : sample 
               104 : sample stage 
               105 : stage 
               106 : detector 
               108 : deflector 
               110 : imaging device 
               111 : control and calculation unit 
               112 : display unit 
               113 : CPU 
               114 : main storage device 
               115 : secondary storage device 
               116 : input unit 
               117 : display processing unit 
               118 : setting processing unit 
               120 : stage control device 
               130 : deflection control device 
               201 : observation image displaying portion 
               202 : observation image importing portion 
               203 : observation position displaying portion 
               205 : observation magnification setting portion 
               206 : observation position displaying portion-magnification setting portion 
               207 : observation position indicator 
               501 : sample stage simulating FIG. 
               502 : sample chamber cross-section simulating FIG. 
               503 : center indicator 
               504 : continuous image importing portion 
               505 : deflection degree displaying indicator 
               506 : deflection canceling function 
               507 : movable range frame 
               508 : coordinate registering portion 
               509 : magnification changing portion 
               510 : stage rotation angle indicator 
               701 : magnification conjunction function executing portion 
               801 : magnification conjunction function executing portion 
               901 : observation image non-displaying function 
               902 : Z-direction image switching function