WO2016088260A1 - Charged particle beam device, chamber scope, and target object detection method - Google Patents

Abstract

In this charged particle beam device, an object to be detected can be automatically distinguished and identified without limiting the camera type, the position and the direction of the camera and the object to be detected, and, regardless of whether or not light is transmitted through a sample. Above a stage (105) provided inside a sample chamber (101) of a charged particle beam device, an object to be detected, such as a sample stage (104), is irradiated with light from a light source (107) to image with a camera (108) the object to be detected, the sample chamber (101) serving as a background. Then, a processor (1101) processes the image of the object to be detected, which has been imaged by the camera (108). The object to be detected and the sample chamber (101) are constituted from different materials, and the wavelength of the light from the light source (107) is set in such a manner that the reflectance of the object to be detected is different from the reflectance of the sample chamber (101).

Description

Charged particle beam apparatus, chamber scope, and object detection method

The present invention relates to a charged particle beam apparatus, a chamber scope, and an object detection method, for example, an observation technique in a charged particle beam apparatus.

A charged particle beam apparatus is an apparatus that performs observation using a charged particle beam, and a detection target (sample stage) needs to be placed in a vacuum in order to prevent scattering of charged particles. For this reason, the sample cannot be visually confirmed, and a method using an optical camera for confirming the inside of the sample chamber is known. For example, in observation using a charged particle beam device, an optical camera is attached as a means for specifying the state and location of a sample installed in a sealed vacuum sample chamber, and the camera image is displayed on an external monitor in real time. It is a method to confirm.

However, the method of displaying the inside of the sample chamber on an external monitor and visually confirming it has a problem that it is necessary to keep an eye on the image acquired mainly by the charged particles to be observed. In this way, with the method of observing with an optical camera, the image to be observed and the image of the external monitor for confirming the sample chamber cannot be visually confirmed at the same time. There is a problem that there is no.

Therefore, a method of automatically detecting the detection target and improving the throughput can be considered. However, in the illumination method used in the past, the detection target and the sample chamber that is the background are made of metal, so that the entire image is brightly shining, and only the detection target is automatically extracted from the acquired image alone. It is difficult.

In order to automatically detect the detection target in such an environment, there is an approach for detecting the target by emphasizing the edge portion, for example. For example, Patent Documents 1 and 2 disclose a method of automatically detecting a detection target by irradiating the edge portion of the detection target with light, photographing the irradiation light with a camera installed on the opposite side of the light source with respect to the detection target. Yes.

JP 2011-134974 A JP 2010-225825 A

However, although Patent Document 1 attempts to automatically detect an edge portion of a sample, it is intended for a thin edge and light needs to pass through a part of the sample.

Further, although Patent Document 2 deals with a case where light does not pass through the sample, it is necessary to install a detection target (sample stage) between the sample and the LED light source. Therefore, the cameras that can be used are limited to characteristic ones, and the viewing angle of the camera with respect to the edge is limited. For this reason, it cannot be applied to a sample chamber of a charged particle beam apparatus in which the installation location is limited, or an object without an edge portion (for example, an observation location inside the sample) cannot be used, and is not general purpose.

The present invention has been made in view of such a situation, and does not limit the position and direction of the camera and the detection target, the type of the camera, and the detection target regardless of whether light passes through the sample. A technology that enables automatic identification and identification is provided.

In the present invention, in order to solve the above-described problems, light is irradiated from a light source to a detection target placed on a stage provided in a sample chamber of the charged particle beam apparatus, and the light is irradiated against the background of the sample chamber. The detected object is imaged with a camera. And a processor processes the image of the detection target imaged with the camera. Here, the detection target and the sample chamber are made of different materials, and the wavelength of light from the light source is set so that the reflectance of the detection target is different from the reflectance of the sample chamber.

Further features related to the present invention will become apparent from the description of the present specification and the accompanying drawings. The embodiments of the present invention can be achieved and realized by elements and combinations of various elements and the following detailed description and appended claims.

It should be understood that the descriptions in this specification are merely exemplary, and are not intended to limit the scope of the claims or the application of the present invention in any way.

According to the present invention, the position and state of the detection target can be automatically detected without limiting the position and direction of the camera and the detection target, and the type of the camera.

It is a figure which shows the example of schematic structure of the charged particle beam apparatus by embodiment of this invention. It is a figure which shows the light source arrangement example in the chamber scope by embodiment of this invention. It is a figure which shows the structural example for automatically detecting the position of object in the sample chamber of a charged particle beam apparatus. It is a figure which shows the relationship between the wavelength and reflectance in aluminum and iron. It is a figure which shows the example of the line profile of the Y direction of a X direction center coordinate. It is a figure which shows the coordinate direction in the acquired image. It is a flowchart for demonstrating the process which calculates | requires the coordinate value of a sample stand from the acquired profile. It is a figure which shows the charged particle beam apparatus (scanning electron microscope) including the structural example for detecting the direction of a sample stand automatically. 10 is a flowchart for explaining a process of automatically detecting the direction (front) of the sample stage 104 (aligning the detection marker 801 with the front of the chamber scope 106). FIG. 2 is a diagram showing a structure of a sample holder 1001 placed on a stage 105 and a sample stage 104 placed on the sample holder 1001. When the sample stage 104 is detached from the sample holder 1001 and the height is adjusted and the sample is observed again, the previous observation position (stage rotation angle) may be different from the current observation position (stage rotation angle). It is a figure which shows that there exists. It is a figure which shows that the picked-up image by the last observation and the picked-up image by this observation differ. It is a figure which shows a mode that the direction of the sample stand 104 is adjusted with the stage 105 so that the marker 801 for a detection may come in front of the chamber scope 106 before observation. 5 is a flowchart for explaining processing for automatically detecting the outer diameter of a sample stage 104 in a charged particle beam apparatus (scanning electron microscope). FIG. 6 is a diagram illustrating a configuration example of a UI (User Interface) operation screen displayed in order to avoid a collision between an upper portion of a sample stage 104 and a detector or an objective lens in a charged particle beam apparatus (scanning electron microscope). It is a figure which shows the relationship between the wavelength of the laser (light source) regarding each material, and a reflectance.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be denoted by the same numbers. The attached drawings show specific embodiments and implementation examples based on the principle of the present invention, but these are for understanding the present invention and are not intended to limit the present invention. Not used.

This embodiment has been described in sufficient detail for those skilled in the art to practice the present invention, but other implementations and configurations are possible without departing from the scope and spirit of the technical idea of the present invention. It is necessary to understand that the configuration and structure can be changed and various elements can be replaced. Therefore, the following description should not be interpreted as being limited to this.

Furthermore, as will be described later, the embodiment of the present invention may be implemented by software running on a general-purpose computer, or may be implemented by dedicated hardware or a combination of software and hardware.

<Configuration of charged particle beam device>
FIG. 1 is a diagram illustrating a schematic configuration example of a charged particle beam apparatus according to an embodiment of the present invention. The charged particle beam apparatus includes a sample chamber 101 that maintains a vacuum state so that the charged particle beam is not scattered, an objective lens 102 that finally converges the charged particle beam onto the sample, and detection that detects a signal obtained from the sample. A vessel 103, a sample stage 104 for placing a sample, a stage 105 for mounting the sample stage 104 and moving an observation position, a chamber scope 106 for grasping the position of the sample stage 104, and a chamber scope A control device (processor such as a microcomputer) 109 for controlling a light source (LED) and an arithmetic device (computer) 110 that executes various calculations are included.

The chamber scope 106 has an illumination 107 for illuminating the inside of the sample chamber 101 and an optical camera 108 for taking an image in the sample chamber 101 as a configuration for detecting the sample position. The control device 109 has an LED control unit 1091 for performing lighting control or light amount control of the LED illumination. The LED control unit 1091 may be configured by a program. The arithmetic device 110 is configured by a computer, and includes a CPU (processor) 1101 that executes various programs, a memory 1102 that stores various programs, an input device such as a mouse and a keyboard, and an output device such as a display and a printer. An output device 1103 and a storage device 1104 that stores various parameters and the like are included. The memory 1102 includes, as programs, a camera image acquisition unit 11021 that acquires an image of an optical camera, an image processing unit 11022 that processes the captured image, an arithmetic processing unit 11023 that specifies a position from the processed image, and a processing result And a result output unit 11024 for outputting.

<Configuration of chamber scope>
FIG. 2 is a diagram illustrating an arrangement example of light sources of the chamber scope according to the embodiment of the present invention. FIG. 2 shows the chamber scope 106 viewed from the direction of the arrow 111 (FIG. 1).

In the chamber scope 106 according to the embodiment of the present invention, the camera (CMOS camera or CCD camera) 201 and the plurality of light sources 202 to 204 are installed such that the imaging direction of the camera 201 and the light irradiation direction of the light source are the same. ing. As an example of a combination of a plurality of light sources, a combination of a white LED 202, a blue LED 203, and an infrared LED 204 can be given. The light sources of the white LED 202, the blue LED 203, and the infrared LED 204 can be switched according to an operator's instruction. Specifically, the operator inputs a light source switching instruction using an input device (not shown) provided in the control device 109, and the LED control unit 1091 emits any LED in response to the instruction. To control. Note that the infrared LED is used because the emission wavelength is out of the detection sensitivity of the SE (secondary electron) detector, so that simultaneous observation of the SE image and the chamber scope is facilitated. For observation, a red LED may be used instead of the infrared LED.

As described above, by appropriately switching the color of the light from the light source, it is possible to irradiate the sample stage 104 with the optimum light according to the situation.

<Process overview: Measurement principle>
FIG. 3 is a diagram for explaining the principle for automatically grasping (detecting) the state and position of the detection target 301 (corresponding to the sample stage 104 in FIG. 1) in the charged particle beam apparatus having the above configuration. .

The control device 109 turns on the illumination 107 of the chamber scope 106 in response to an instruction from the operator, and irradiates the detection target 301 and the background material 302 with light. At this time, with respect to the light of the illumination 107, light having a wavelength such that there is a difference in reflectance between the detection target 301 and the background material 302 is selected. In this state, an image is acquired using the optical camera 108, and the CPU 1101 of the arithmetic device 110 captures an image using the camera image acquisition unit 11021. Then, the CPU 1101 processes the captured image using the image processing unit 11022. For example, processing such as application of an edge enhancement filter for enhancing an edge, binarization processing of an acquired image, gray scale conversion of an image, and color extraction may be performed. Further, not only simple filter processing but also image processing such as pattern matching may be used to improve the accuracy.

The CPU 1101 performs an operation for obtaining the coordinates of the detection target 301 on the image thus processed. For example, the CPU 1101 extracts a boundary between the detection target 301 and the background material 302 by obtaining a coordinate value having the highest luminance for the image whose edge is enhanced by the image processing unit 11022, and outputs the boundary as the detection target coordinate. May be. In order to further improve the accuracy, for example, the edge-enhanced image is integrated in the X direction or the Y direction (note that it is a coordinate system for image processing, not the coordinate system of the sample stage in the charged particle beam apparatus), and the profile The position with the highest luminance may be used as the detection target coordinates. This may be performed only in the X direction or the Y direction, or may be performed in both the X direction and the Y direction. Note that such processing need not be performed with edge enhancement, and may be applied to grayscale images or color extracted images.

Further, as a method of obtaining the coordinates of the detection target, for example, region division may be performed on the binarized image, the area of the region may be obtained, and the coordinates of the region closest to the area of the target to be obtained may be output.

On the other hand, the center of gravity of a white area obtained simply by binarization may be output as a coordinate value without dividing the area by appropriately setting a threshold value.

Also, coordinates obtained by pattern matching processing may be output.

For the image obtained as described above, the CPU 1101 may simply output a coordinate value by using the result output unit 11024, or may display it superimposed on the acquired image. The value used as the evaluation value may also be output together and output as information on the reliability of the result.

By adopting such a configuration and executing the above-described processing, it becomes possible to automatically obtain the target coordinates.

<Automatic detection of sample stage height>
A process for automatically detecting the height of the sample stage 104 in the scanning electron microscope will be described. Here, with respect to the illumination 107, illumination having a wavelength such that the reflectance differs between the wall of the sample chamber 101 and the sample stage 104 is selected. For example, when the sample stage 104 is made of aluminum and the sample chamber 101 is made of iron, the illumination 107 is based on the relationship between the wavelength of light and the reflectance in aluminum (Al) and iron (Fe) shown in FIG. Select the color. That is, FIG. 4 shows that, in the combination of aluminum and iron, if blue illumination 107 with a short wavelength is selected, the reflectance differs between aluminum and iron, and a luminance difference occurs between the respective materials. . Therefore, in this example, by adopting blue light as the light source, a bright image can be acquired only for the sample stage 104.

The illumination 107 may not be blue light, and the wavelength may be selected so that the reflectance of the sample stage (inspection object) 104 and the reflectance of the sample chamber (background material) 101 are different. Other combinations of the inspection object, the background material, and the light source (illumination color) for brightening only the inspection object will be described later.

The image acquired in this way is converted into a grayscale image by the image processing unit 11022. This conversion is not limited to grayscale conversion, and an image obtained by extracting each color may be used, or an image obtained by extracting an edge may be used. Then, for the converted image, the arithmetic processing unit 11023 acquires a line profile in the Y direction of the center coordinate in the X direction. FIG. 5 is a diagram illustrating an example of the acquired luminance profile. If this profile is used, the position of the sample stage 104 can be easily specified. That is, it is specified that the location where the luminance intensity exceeds a predetermined threshold is the upper end of the sample stage 104. Therefore, the distance from the position of the lens aperture to the sample stage 104 can be known. Here, the X direction and the Y direction are coordinate directions in the acquired image as shown in FIG. 6, and are different from the coordinates of the charged particle beam apparatus. The Y direction (Y coordinate) in FIG. 6 corresponds to the Z coordinate of the charged particle beam apparatus (the same applies to the Z coordinate in FIG. 5). Further, this profile may be displayed on a display included in the input / output device 1103.

FIG. 7 is a flowchart for explaining processing for obtaining the coordinate value of the sample stage from the acquired profile.

(I) Step 701
In response to the operator's instruction, the control device 109 irradiates the sample chamber 101 with blue light using the LED control unit 1091.

(Ii) Step 702
The CPU 1101 of the arithmetic device 110 acquires an image of the target (sample stage 104 and sample chamber 101) irradiated with blue light using the camera image acquisition unit 11021, and acquires the image acquired using the image processing unit 11022, for example. Convert to a grayscale image. Then, the CPU 1101 uses the arithmetic processing unit 11023 to obtain a profile at the X-axis center (fixed Y coordinate) for the image converted to grayscale.

(Iii) Step 703
The CPU 1101 uses the arithmetic processing unit 11023 to calculate the differential value of the profile acquired in step 703.

(Iv) Step 704
The CPU 1101 uses the arithmetic processing unit 11023 to determine whether or not the differential value obtained in step 704 is equal to or greater than a preset threshold value (predetermined threshold value). If the differential value of the profile is less than the predetermined threshold (No in step 704), the process proceeds to step 705. If the differential value is equal to or greater than the predetermined threshold (Yes in step 704), the process proceeds to step 706.

(V) Step 705
The CPU 1101 moves the profile acquisition position to the next Y coordinate. Then, the processing in steps 702 to 704 is repeated.

(Vi) Step 706
Using the arithmetic processing unit 11023, the CPU 1101 sets the current Y coordinate as the upper end of the sample stage 104, and ends the sample stage height automatic detection process.

And CPU1101 outputs the calculated | required coordinate value using the result output part 11024. FIG. This coordinate value can be used to limit the operation of the stage, for example. Specifically, when there is a possibility that the sample stage 104 collides with the detector or the objective lens, it can be used as a safety function that automatically stops the movement of the stage 105. In addition, since the distance between the objective lens and the sample can be determined from the height of the sample stage 104, the focus position of the charged particle beam apparatus (scanning electron microscope) can be roughly positioned, and the speed of automatic focusing can be increased. It becomes like this.

<Automatic detection processing for sample stage>
FIG. 8 is a diagram showing a charged particle beam apparatus (scanning electron microscope) including a configuration example for automatically detecting the orientation of the sample stage.

When detecting the orientation of the sample stage, a detection marker (hereinafter also simply referred to as “marker”) 801 made of a material having a reflectance different from that of the sample stage 104 is attached to the side surface of the sample stage 104. . For example, the sample stage 104 is made of aluminum, and a screw hole is cut in the side surface of the sample stage 104. Then, a screw made of iron is attached to this screw hole as the detection marker 801. In contrast, the sample stage 104 may be made of iron and the screw may be made of aluminum. In addition, the detection marker attached to the side surface does not need to be a screw. For example, a hole may be made in the sample stage 104 and a pin or the like may be inserted. As a result, only the detection marker 801 is displayed in black in the brightly displayed portion of the sample stage 104, so that it can be easily determined whether or not the marker 801 is in front.

FIG. 9 is a flowchart for explaining a process of automatically detecting the direction (front) of the sample stage 104 (aligning the detection marker 801 with the front of the chamber scope 106).

(I) Step 901
In response to the operator's instruction, the control device 109 irradiates the sample chamber 101 with blue light using the LED control unit 1091.

(Ii) Step 902
The CPU 1101 of the arithmetic device 110 uses the camera image acquisition unit 11021 to acquire an image of the target (the sample stage 104 and the detection marker 801) irradiated with blue light.

(Iii) Step 903
The CPU 1101 uses the arithmetic processing unit 11023 to determine whether or not the image of the marker 801 is included in the image acquired in step 902. For example, the image of the detection marker 801 is included in the captured image when the sample stage 104 is facing the front, but when the detection marker 801 is at a position opposite to the chamber scope 106 direction, the image of the detection marker 801 is It is not included in the captured image. In addition, when the detection marker 801 is not directly in front, the image of the detection marker 801 is a dull image compared to the image in front of it. For example, if the detection marker has a circular shape, an elliptical image is acquired. Therefore, it may be determined that the detection marker 801 is detected when the aspect ratio of the ellipse is equal to or greater than a predetermined value. Specifically, an image obtained when the detection marker 801 is at least in front is stored in the storage device 1104 in advance, and the stored image is compared with the image acquired in step 902, whereby the detection marker 801 is stored. Confirm existence. Alternatively, the presence of the detection marker 801 may be confirmed by observing the luminance of the image captured in step 902. In this case, the average value of the luminance of each region is taken and a histogram is created. Since the luminance of the area where the detection marker 801 is present is lower than that of the other areas, the histogram takes a low value. An area where the value of this histogram is lower than a predetermined value may be determined as the position of the detection marker 801.

If it is determined that the detection marker 801 does not exist (No in Step 903), the process proceeds to Step 904. If it is determined that the detection marker 801 is present (Yes in step 903), the process proceeds to step 905.

(Iv) Step 904
The CPU 1101 notifies the control device 109 that the detection marker 801 has not been detected. Then, the control device 109 rotates the stage 105 using the stage control unit 802 and moves to the next rotation angle. Then, the processing of steps 902 and 903 is repeated.

(V) Step 905
The CPU 1101 ends the profile acquisition, and ends the automatic detection process for the sample stage with the current rotation angle as the front.

(Vi) About Absolute Value of Sample Stand Rotation Angle FIG. 10 is a diagram showing the structure of the sample holder 1001 placed on the stage 105 and the sample stand 104 placed on the sample holder 1001. The sample holder 1001 has a stage attachment portion 10011 for attaching the sample holder 1001 to the stage 105 and a height adjusting screw 10012 for adjusting the height of the sample holder 1001. The height of the sample holder 1001 is adjusted by the height adjusting screw 10012. Therefore, when the sample stage 104 is detached from the sample holder 1001, the height is adjusted, and the sample is observed again, as shown in FIG. 11, the previous observation position (stage rotation angle) and the current observation are shown. The position (stage rotation angle) may be different. In FIG. 11, a dotted-line rectangle 11002 indicates the reproduction of the previous observation position. In a charged particle beam apparatus (scanning electron microscope), the previous observation position can be reproduced by storing stage coordinates and magnification information in the storage device 1104.

However, even if the previous observation position can be reproduced, the same image as the previous observation cannot be taken as shown in FIG.

Therefore, by adjusting the direction of the sample stage 104 with the stage 105 so that the detection marker 801 is in front of the chamber scope 106 before the observation (see FIG. 13), the same image as the previous observation is taken. Will be able to. As a result, the sample 11001 at the previous observation position can be observed again at a higher magnification, or can be observed again under different optical conditions.

Since the specific orientation of the sample stage 104 can be adjusted for each observation in this way, the absolute value of the sample stage rotation angle can be known, and the conditions at the previous observation can be reproduced. As a result, an image in the same field of view as the captured image can be captured again based on the previously stored coordinate value and magnification.

<Automatic detection processing of sample table outer diameter>
FIG. 14 is a flowchart for explaining processing for automatically detecting the outer diameter of the sample stage 104 in the charged particle beam apparatus (scanning electron microscope).

(I) Step 1401
In response to the operator's instruction, the control device 109 irradiates the sample chamber 101 with blue light using the LED control unit 1091.

(Ii) Step 1402
The CPU 1101 executes the automatic detection processing (steps 902 to 905) for the sample stage in FIG. 9, and moves the position of the detection marker 801 to the front.

(Iii) Step 1403
The control device 109 uses the stage control unit 802 to rotate the stage 105 by an arbitrary angle. The rotation angle may be determined in advance.

(Iv) Step 1404
The CPU 1101 measures the amount of movement of the detection marker 801 using the arithmetic processing unit 11023. This is because the amount of movement of the detection marker 801 varies depending on the outer diameter size of the sample stage 104.

(V) Step 1405
The CPU 1101 uses the image processing unit 11022 to calculate the outer diameter of the sample stage 104 by image processing from the movement amount obtained in step 1404, and ends the automatic detection process of the sample stage outer diameter.

By using this processing, it is possible to automatically set the sample stage size that has been manually set by an operator in the past, thereby improving throughput and preventing setting errors. Here, the processing is described when the sample stage 104 is circular. However, even if the sample stage 104 is rectangular or the like, the outer peripheral value of the sample stage 104 can be obtained if the relative positional relationship between the rotation angle and the sample stage is known. .

<UI operation screen>
FIG. 15 is a diagram showing a configuration example of a UI (User Interface) operation screen displayed to avoid collision between the upper part of the sample stage 104 and the detector or the objective lens in the charged particle beam apparatus (scanning electron microscope). is there.

The operator can adjust the position of the upper limit line adjustment 1502 by moving the upper limit line adjustment unit 1503 up and down with a mouse or the like on the UI operation screen shown in FIG. 15 displayed on a display (not shown). This limits the upper limit of the sample stage 104.

Further, on the UI operation screen, for example, a scale display 1501 that can intuitively display the distance from the detector or the objective lens may be displayed. Furthermore, the area 1504 where the sample stage 104 cannot enter may be masked and displayed.

By adopting such a UI operation screen, for example, it is possible to intuitively understand whether it is possible to move to an analysis position when analyzing with an external detector. In addition, in order to improve the image quality of captured images when multiple option detectors are installed, it is possible to intuitively understand which detectors may come into contact with the sample when the lens and sample are brought close to each other. It becomes possible.

<Combination of inspection object and background material and light source wavelength applicable to the present invention>
In the embodiment described above, aluminum is used as the material for the inspection target (sample stage 104), iron is used as the material for the background (sample chamber 101), and a blue LED (wavelength: 465 to 475 nm) is used as the light source. This combination is not limited to this. Therefore, the following is a description of the case where the principle of the present invention can be applied in addition to the above combinations.

FIG. 16 is a diagram showing the relationship between the wavelength of the laser (light source) and the reflectance for each material. According to this graph and / or experiments conducted by the inventors, it was found that the following combinations are possible.

(I) When aluminum is used as the material of the sample stage 104 and copper is used as the material of the sample chamber 101, green light, blue light, and ultraviolet light having a wavelength of 550 nm or less can be used.

(Ii) When silver is used as the material of the sample stage 104 and copper is used as the material of the sample chamber 101, green light, blue light, and ultraviolet light having a wavelength of 400 to 550 nm can be used.

(Iii) When aluminum is used as the material of the sample stage 104 and gold is used as the material of the sample chamber 101, it has been found that ultraviolet light having a wavelength of 400 nm or less can be used. Note that the relationship between wavelength and reflectance for gold is not shown in FIG.

(Iv) When iron is used as the material of the sample stage 104 and silver is used as the material of the sample chamber 101, ultraviolet light, blue light, green light, yellow light, orange light, red light, and infrared light having a wavelength of 400 nm or more are used. Can be used.

(V) When iron is used as the material of the sample stage 104 and aluminum is used as the material of the sample chamber 101, blue light, green light, yellow light, orange light, and red light having a wavelength of 400 to 800 nm can be used.

Note that it is desirable to select the combination of (i) to (iii) rather than the combination of (iv) and (v) because the sample stage 104 can be illuminated more clearly.

<Summary>
(I) A charged particle beam apparatus according to an embodiment of the present invention acquires an image of a detection target (sample stage) placed on a stage and performs predetermined image processing on the image, thereby detecting the detection target. Detect the state and position (including height). Here, the detection target and the sample chamber (at least the wall surface as a background when the detection target is photographed with a camera) are made of different materials. In this case, the wavelength of the light emitted from the light source that irradiates the detection target with light is set so that the reflectance of the detection target is different from the reflectance of the sample chamber. For example, it is desirable that the wavelength of the light of the light source is set so that the reflectance of the detection target is higher than the reflectance of the sample chamber. By doing so, the luminance of the detection target can be made higher than that of the background, so that the state and position of the detection target can be easily and automatically detected.

More specifically, a position where the luminance of the image of the sample table is higher than a predetermined threshold is detected as the height of the sample table. When the reflectance of the background (wall surface of the sample chamber) is higher than that of the sample table, the position where the luminance of the image of the sample table is lower than the predetermined threshold is detected as the height of the sample table. Since the height can be detected by the image processing in this way, it is possible to automatically grasp the height position of the detection target (sample stage).

On the other hand, in the embodiment of the present invention, the direction (angle) of the sample stage can be automatically detected. That is, a marker having a reflectance different from that of the sample table when the light from the light source is irradiated is provided at a predetermined position of the sample table. And the image of a sample stand and a marker is acquired with a camera, and the direction of a sample stand is detected by the luminance difference between them. The relationship between the orientation of the sample stage (angle from the reference position) and the shape of the marker image is stored in advance on a table, etc., and it detects not only the state of the sample stage in front but also the state at an arbitrary angle. You may make it do.

Also, the amount of movement of the marker when the stage is rotated is measured, and the size of the sample stage (outer diameter and area of the sample stage) is calculated from the amount of movement. The shape of the pedestal portion of the sample stage is not limited to a circle, and may be a square, a rectangle, or other polygons. However, it is necessary to recognize the relative positional relationship between the rotation angle and the sample stage.

The detection target (sample stage) is made of aluminum or silver, and the sample chamber is made of iron, copper, or gold. As the light source, when the detection object-sample chamber combination is aluminum-iron, aluminum-copper, and silver-copper, a light source that emits blue light, green light, or ultraviolet light is used. When the combination is aluminum-gold, a light source that emits ultraviolet light is used. When the detection object-sample chamber combination is iron-silver, the light source emits light (ultraviolet light, blue light, green light, yellow light, orange light, red light, infrared light) having a wavelength of 400 nm or more. Can be used. Further, when the detection object-sample chamber combination is iron-aluminum, a light source that emits light (blue light, green light, yellow light, orange light, red light) having a wavelength of 400 nm to 800 nm can be used. By using such a combination of the detection target (sample stage), the material of the sample chamber, and the light source, it becomes possible to distinguish the detection target from the background in the captured image of the camera. It becomes possible to do.

(Ii) The chamber scope according to the embodiment of the present invention has a plurality of light sources for irradiating the inspection target with light and a control device for switching the light sources. As a combination of a plurality of light sources, for example, a light source that emits blue light, a light source that emits white light, and a light source that emits infrared light are employed. As described above, blue light is used to acquire position information (height and position coordinates) of a detection target, white light is used to acquire color information, and infrared light is used to observe a sample. Used. Since the emission wavelength of the infrared light deviates from the detection sensitivity of the SE (secondary electron) detector, the SE image and the chamber scope can be observed simultaneously. For observation, red light may be used instead of infrared light.

In the chamber scope, the direction of the camera and the direction of the plurality of light sources (light irradiation direction) are the same.

(Iii) The functions according to the embodiment of the present invention (functions given in the flowchart) can also be realized by software program codes. In this case, a storage medium in which the program code is recorded is provided to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for supplying such program code, for example, a flexible disk, CD-ROM, DVD-ROM, hard disk, optical disk, magneto-optical disk, CD-R, magnetic tape, nonvolatile memory card, ROM Etc. are used.

Also, based on the instruction of the program code, an OS (operating system) running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing. May be. Further, after the program code read from the storage medium is written in the memory on the computer, the computer CPU or the like performs part or all of the actual processing based on the instruction of the program code. Thus, the functions of the above-described embodiments may be realized.

Further, by distributing the program code of the software that realizes the functions of the embodiment via a network, the program code is stored in a storage means such as a hard disk or a memory of a system or apparatus, or a storage medium such as a CD-RW or CD-R And the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage means or the storage medium when used.

Finally, it should be understood that the processes and techniques described herein are not inherently related to any particular equipment, and can be implemented by any suitable combination of components. In addition, various types of devices for general purpose can be used in accordance with the teachings described herein. It may prove useful to build a dedicated device to perform the method steps described herein. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined. Although the present invention has been described with reference to specific examples, these are in all respects illustrative rather than restrictive. Those skilled in the art will appreciate that there are numerous combinations of hardware, software, and firmware that are suitable for implementing the present invention. For example, the described software can be implemented in a wide range of programs or script languages such as assembler, C / C ++, perl, shell, PHP, Java (registered trademark).

Furthermore, in the above-described embodiment, control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines on the product are necessarily shown. All the components may be connected to each other.

In addition, other implementations of the invention will become apparent to those skilled in the art from consideration of the specification and embodiments of the invention disclosed herein. Various aspects and / or components of the described embodiments can be used singly or in any combination. The specification and specific examples are merely exemplary, and the scope and spirit of the invention are indicated in the following claims.

DESCRIPTION OF SYMBOLS 101 ... Sample chamber 102 ... Objective lens 103 ... Detector 104 ... Sample stand 105 ... Stage 106 ... Chamber scope 107 ... Illumination 108 ... Optical camera 109 ... Control device 110 ... arithmetic device 201 ... camera 202 ... white LED
203 ... Blue LED
204: Infrared LED

Claims (15)

1. A sample chamber for storing the detection target on the stage;
   A light source that irradiates light to the detection target; a camera that images the detection target irradiated with light with the sample chamber as a background;
   A processor for processing the detection target image captured by the camera,
   The detection object and the sample chamber are made of different materials,
   The charged particle beam device is characterized in that the wavelength of the light of the light source is set so that the reflectance of the detection target is different from the reflectance of the sample chamber.
2. In claim 1,
   The charged particle beam apparatus according to claim 1, wherein the wavelength of light from the light source is set such that the reflectance of the detection target is higher than the reflectance of the sample chamber.
3. In claim 1,
   The detection target is a sample stage placed on the stage by an operator,
   The charged particle beam apparatus, wherein the processor detects, as the height of the sample stage, a position where the luminance of the image of the sample stage is higher than a predetermined threshold.
4. In claim 1,
   The detection target is a sample stage placed by the operator on the stage, and a marker having a reflectance different from that of the sample stage when the light from the light source is irradiated on a predetermined position of the sample stage. Provided,
   The charged particle beam apparatus, wherein the processor detects the orientation of the sample stage by detecting the presence of the marker from the image of the sample stage.
5. In claim 4,
   The charged particle beam apparatus, wherein the processor measures a movement amount of the marker when the stage is rotated, and calculates a size of the sample stage from the movement amount.
6. In claim 3,
   The charged particle beam apparatus, wherein the processor displays a user interface for setting an upper limit of a moving height of the sample stage on a screen.
7. In claim 1,
   The detection object is made of aluminum or silver, and the sample chamber is made of iron, copper, or gold,
   The light source emits blue light, green light, or ultraviolet light when the detection object-sample chamber combination is aluminum-iron, aluminum-copper, and silver-copper, and when the combination is aluminum-gold. Is a charged particle beam device that irradiates ultraviolet light.
8. A chamber scope for imaging the sample chamber of a charged particle beam device,
   A plurality of light sources for irradiating the detection target contained in the sample chamber with light;
   With the sample chamber as a background, a camera that images the detection target irradiated with light;
   A control device that switches and controls the plurality of light sources,
   The plurality of light sources include a light source that emits blue light, a light source that emits white light, and a light source that emits infrared light,
   In response to an input instruction, the control device switches between a blue light source, a white light source, and an infrared light source, and irradiates the detection target with light.
9. In claim 8,
   A chamber scope characterized in that an orientation of the camera and an orientation of the plurality of light sources are the same.
10. Irradiating an object placed on a stage of a sample chamber of a charged particle beam device with light emitted from a light source;
    With the sample chamber as a background, imaging the object irradiated with the light with a camera;
    A processor processing an image of the object captured by the camera;
    The object and the sample chamber are made of different materials,
    The wavelength of the light from the light source is set so that the reflectance of the object is different from the reflectance of the sample chamber.
11. In claim 10,
    The wavelength of the light from the light source is set so that the reflectance of the object is higher than the reflectance of the sample chamber.
12. In claim 10,
    The object is a sample stage placed on the stage by an operator,
    Furthermore, the said processor includes the process of detecting the position where the brightness | luminance of the image of the said sample stand is higher than a predetermined threshold value as the height of the said sample stand, The object detection method characterized by the above-mentioned.
13. In claim 10,
    The object is a sample table placed by the operator on the stage, and a marker having a reflectance different from that of the sample table when the light from the light source is irradiated to a predetermined position of the sample table. Provided,
    The object detection method further comprising the step of detecting the orientation of the sample stage by detecting the presence of the marker from the image of the sample stage.
14. In claim 13,
    Furthermore, the processor includes a step of measuring a movement amount of the marker when the stage is rotated, and calculating a size of the sample stage from the movement amount.
15. In claim 12,
    Furthermore, the said processor includes the process of displaying the user interface for setting the upper limit of the moving height of the said sample stage on a screen, The target object detection method characterized by the above-mentioned.

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