JP5018868B2 - Sample observation method and apparatus - Google Patents

Description

  The present invention relates to a sample observation method and apparatus for use in a detailed automatic inspection method for a defect or an attached foreign matter generated in a semiconductor manufacturing process.

As a method of observing a sample and seeing foreign matter / defects in detail, for example, there is a method as described in Patent Document 1.
In this method, after moving to an abnormal portion existence area and acquiring a defect image based on coordinate data obtained in advance from another abnormality inspection apparatus, a foreign object / defect position is specified by some method, and enlarged imaging is performed.

Japanese Patent Laid-Open No. 9-139406

Although not clearly described in Patent Document 1 as the above-described prior art, the present inventors have examined and found that there are the following problems.
That is, the success or failure of the defect extraction process can only be judged by looking at the collected images, and there is no means for the user to check the validity. Moreover, when it fails, it cannot know how it failed. For this reason, it takes time to set the shooting conditions that facilitate the defect extraction process.
Also, when a foreign object / defect area is identified from a defect image, which is an image containing a foreign object / defect, or a shape is recognized, and there is a pattern in the background of the foreign object / defect, the same background as the defect image It is desirable to obtain and compare together reference images, which are images having patterns and no defects.
Therefore, when inspecting in detail, for example, by enlarging the foreign matter / defective part, if the defect image is acquired first as in the conventional example, the stage is moved so that the reference image is in the field of view. After acquiring and calculating the foreign substance / defect position, it is necessary to move the stage again so that the defective portion enters the field of view, and the amount of movement of the stage increases, that is, it takes an image acquisition time.
Further, when the imaging field size of the defect image is close to the positioning error of the stage, it is difficult to position in the background area similar to the defect image, and it is difficult to acquire the reference image.
In addition, if the reference image corresponding to the defect image is always captured, the number of images captured increases in proportion to the number of defects, and the image acquisition time also increases.
An object of the present invention is to solve the problems of the prior art and to provide a material observation method and apparatus capable of efficiently observing defects in a short time.

In order to achieve the above object, according to the present invention, in a method for observing a sample, an image obtained by imaging a desired region of the sample is displayed on the first screen, and the image displayed on the screen is enlarged. The area to be observed is displayed on the image, and an enlarged image obtained by imaging the area to be observed by magnifying the displayed sample is displayed on the second screen.
In order to achieve the above object, according to the present invention, in the method for observing a sample, the position of the sample is adjusted so that the desired region of the sample falls within the observation field of the observation means, and the desired region of the sample is obtained. The first image is obtained by imaging at the first magnification, the first image is displayed on the first screen, and the enlarged observation area included in the first image displayed on the screen is displayed on the screen. The enlarged observation area is imaged at a second magnification larger than the first magnification to obtain a second image, and this second image is displayed on the second screen.
Furthermore, in order to achieve the above object, according to the present invention, in the method of observing a sample using a scanning electron microscope, the position of the sample is adjusted so that a desired region of the sample falls within the observation field of view of the scanning electron microscope. Adjust and image a desired region of the sample at the first magnification of the scanning electron microscope to obtain a first image, which is displayed on the first screen and displayed on this screen The first image is compared with the reference image, the enlarged observation area of the first image displayed on the screen is determined based on the comparison, and the image of the determined enlarged observation area is displayed on the second screen. I tried to do it.
Furthermore, in order to achieve the above object, in the present invention, the sample is imaged based on the information on the defect of the sample detected by the inspection apparatus to obtain a reference image not including the defect of the sample, and the sample detected by the inspection apparatus is obtained. The sample is imaged based on the defect information to obtain a defect image including the defect of the sample, the reference image is compared with the defect image to detect the defect on the defect image, and the defect image including the detected defect is detected. A sample observation method is characterized in that a part of the image is captured to obtain an enlarged image of the defect, and the enlarged image of the defect is displayed on the screen.
Furthermore, in order to achieve the above object, in the present invention, the sample is imaged based on the information on the defect of the sample detected by the inspection apparatus to obtain a reference image not including the defect of the sample, and the sample detected by the inspection apparatus is obtained. Based on the defect information, adjust the position of the sample so that the defect enters the field of view of the image, capture the image of the sample whose position has been adjusted, obtain a defect image containing the defect in the sample, and compare the reference image with the defect image Detecting a defect in the defect image, imaging a partial area including the detected defect in the imaging field of view, obtaining an enlarged image of the defect, and displaying the enlarged image of the defect on the screen. It was set as the observation method of the characteristic sample.
Furthermore, in order to achieve the above object, in the present invention, the sample is imaged based on the information on the defect of the sample detected by the inspection apparatus to obtain a reference image not including the defect of the sample, and the sample detected by the inspection apparatus is obtained. The sample is imaged based on the defect information to obtain a defect image including the defect of the sample, the defect is detected by comparing the reference image and the defect image, and a part of the defect image including the detected defect is imaged. An enlarged image of the defect was obtained, an image in which the background area was erased from the enlarged image was created, and the image in which the background area was erased was displayed on the screen.
In order to achieve the above object, according to the present invention, an apparatus for observing a sample includes an imaging unit that captures an image of the sample and obtains an image of the sample, and data relating to a desired region of the sample captured by the imaging unit. Storage means received and stored from, a position control means for controlling the position of the sample relative to the imaging means based on data relating to a desired region of the sample stored in the storage means, and an image of the sample obtained by imaging with the imaging means The display means for displaying the image and the sample whose position is controlled by the position control means are compared with a plurality of images of the first magnification obtained by imaging with the imaging means, thereby detecting a defect in the sample and detecting the first defect. Arithmetic control means for causing the display means to display the image of the defect at a second magnification larger than the magnification together with the image including the defect of the first magnification.
In order to achieve the above object, according to the present invention, a storage means for receiving information from a defect inspection apparatus and storing the information on the defect of the sample obtained by inspecting the sample with an external defect inspection apparatus. An image pickup means for picking up an image of the sample to obtain an image of the sample; a position control means for controlling the position of the sample on the basis of the defect information stored in the storage means; and the position control means for controlling the position. The defect detection means for detecting the position of the defect by comparing the image including the defect and the image including the defect obtained by imaging the sample with the imaging means at the first magnification, and displaying the defect on the screen, and the defect The apparatus includes a defect enlargement display unit that images the defect detected by the detection unit at a second magnification larger than the first magnification by the imaging unit and displays the image on the screen.
In order to achieve the above object, according to the present invention, an apparatus for observing a sample includes an imaging unit that images the sample and obtains an image of the sample, and a sample obtained by inspecting with an external defect inspection apparatus. A position control means for controlling the position of the sample relative to the imaging field of view of the imaging means based on the defect information, and a sample whose position is controlled by the position control means is obtained by imaging at a first magnification by the imaging means. A defect detection unit that compares a non-defect image with an image that includes a defect to detect the position of the defect and displays the image including the defect in which the position of the defect is detected is displayed on the screen, and is displayed on the screen of the defect detection unit The image forming apparatus includes a defect magnification display unit that captures an image of a sample region corresponding to a defect portion of an image including a defect with a second magnification larger than the first magnification by an imaging unit and displays the image on the screen.
That is, the present invention enables the user to confirm the validity of the defect extraction by displaying the extraction result by the defect extraction process superimposed on the defect image.
Also, after acquiring a reference image corresponding to the foreign object / defect image based on the coordinate information of the foreign object / defect position obtained in advance by another inspection apparatus, the amount of movement of the stage can be determined by capturing the foreign object / defect image. The number was reduced and the image acquisition efficiency was improved.
Furthermore, the present invention captures images at two different magnifications, identifies a foreign object / defect position by low-magnification imaging, and images the identified foreign object / defect position at a high magnification, and then corresponds to the foreign object / defect image. High magnification by moving the stage to the reference image position and imaging at low magnification, specifying the imaging center using the region in the low magnification reference image corresponding to the imaging field of view at high magnification as the template, and performing high magnification imaging The high-magnification reference image corresponding to the defect image can be obtained.
For the acquired reference image, the imaging area and the reference image in the chip coordinate system assigned to each chip are recorded, and the reference area is referenced when the imaging area in the chip coordinate of the defect to be inspected is recorded. The efficiency of image acquisition and inspection was improved by using images recorded without acquiring images.

As described above, according to the present invention, since the user can confirm the success / failure of the defect extraction process and the relationship between the two types of magnifications, it is easy to set imaging conditions and magnifications that are easy to extract. be able to.
In addition, since the defect image and the reference image can be efficiently captured by reducing the moving amount of the stage, the image collection time can be reduced.
Further, even in high-magnification imaging that affects the positioning error of the stage, it is possible to stably acquire defect images and reference images, and to perform detailed inspection of defects stably.

It is a front view which shows schematic structure of the observation apparatus of the sample by this invention. 3 is a flowchart showing a sample observation process according to the present invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. 3 is a flowchart showing a sample observation process according to the present invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. 3 is a flowchart showing a sample observation process according to the present invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. It is a figure which shows the image obtained by the observation method of the sample of this invention. 3 is a flowchart showing a sample observation process according to the present invention. It is a figure which shows the defect position on a wafer, and a reference image map. It is a figure which shows the defect position on a wafer, and a reference image map. It is a block diagram which shows schematic structure of the image data collection system by this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of an image collecting apparatus for performing a detailed defect inspection according to the present invention.
In FIG. 1, reference numeral 1 denotes a semiconductor wafer to be inspected, which is fixed to an XY stage 2. The XY stage 2 can be moved in the X and Y directions via the control device 4 by a control signal from the computer 3.
Reference numeral 5 denotes an imaging apparatus using a scanning electron microscope (hereinafter referred to as SEM), which enlarges and images the semiconductor wafer 1. That is, the electron beam 502 emitted from the electron source 501 is converged by the electron optical system 503 and scanned as a sample to irradiate the semiconductor wafer 1, and secondary electrons generated from the semiconductor wafer 1 by this irradiation are detected by the detector 504. And an SEM image of the semiconductor wafer 1 is obtained.
In the imaging device 5, an arbitrary position on the semiconductor wafer 1 can be observed by controlling the XY stage 2. The image of the imaging device 5 is input to the computer 3 and processing such as defect extraction is performed. The processing result is displayed on the monitor 7 via the display switching device 6. The function of the display switching device 6 may be performed by the computer 3.
FIG. 2 shows an example of a procedure for collecting inspection images, and FIG. 3 shows an example of an image acquired by the collecting procedure shown in FIG.
It is assumed that the semiconductor wafer to be inspected is previously inspected by a surface defect inspection device such as a foreign matter inspection device or an appearance inspection device (not shown), and coordinate data of the position of the foreign matter / defects is obtained.
First, a semiconductor wafer 1 to be inspected is loaded on the XY stage 2, and the coordinate system of the XY stage 2 and the coordinate system on the semiconductor wafer 1 are used by using semiconductor design data or obtained defect position data. Perform calibration.
Next, based on the position coordinate data of the defect of the semiconductor wafer 1 stored in the computer 3 in response to a result obtained by inspecting with a surface defect inspection apparatus (not shown) in advance, a command is issued to drive the XY stage 2. 3 to the control device 4, and the control device 4 receives this command and drives the XY stage 2. Here, first, under the command of the computer 3, the control device 4 causes the position of the chip adjacent to the chip having the defect to correspond to the defect on the chip coordinate system within the field of view of the first magnification of the imaging device 5. The position of the stage 2 is controlled so as to be yes, and an image 8 as a reference image is obtained by imaging at the first magnification.
At this time, the imaging position is not limited to the adjacent chip, and may be the same coordinate position in the chip coordinate system of a chip several chips away, or a position having the same pattern even if it is not the same coordinate position. I just need it.
The first magnification is set to a magnification at which the defect enters the field of view when moving to the defect position in consideration of the error of the defect coordinate data obtained in advance and the stage positioning error.
Next, the position of the stage 2 is controlled by the control device 4 so that the defect detected by the surface inspection device enters the field of view of the first magnification of the image pickup device 5, and the defect image 1 is picked up at the first magnification. An image 9 is obtained.
Here, the image 8 and the image 9 obtained by using template matching or the like are aligned, and the defect position 10 in the defect image is calculated by detecting a difference area between the aligned images.
Next, the imaging magnification is set to a second magnification larger than the first magnification, the electron beam scanning region is adjusted and imaging is performed so that the defect position 10 is at the center, and the defect position 10 is set as the image center. An image 11 that is a high-magnification defect image 2 is obtained. As a method of setting the imaging magnification to the second magnification, there is a method of confirming the image at that time on the monitor 7 while narrowing the scanning area of the electron beam, and a cursor on the screen of the monitor 7. There is a method of presetting the scanning region of the electron beam with a line or a light pen.
By obtaining a high-magnification defect image in this way, it becomes possible to inspect in detail the shape of the foreign matter / defect, the surface state, and the like.
At this time, the defect position is identified on the first magnification image captured with the defect set in the field of view, and the SEM scanning region is narrowed down to the identified defect position and its periphery. Since a magnification image can be obtained, foreign matters and defects can be reliably captured in the field of view of the high magnification image.
In addition, by capturing the image 9 after capturing the image 8, the image 11 can be acquired without the need to move the stage 2 after the calculation of the defect position 10, so that a high-magnification defect image is efficiently acquired. be able to.
At this time, the difference area between the image 8 and the image 9 is displayed on the monitor 7 so as to be superimposed on the image 9, thereby informing the user how the defect area has been extracted.
In addition, while displaying a low-magnification image or while displaying a low-magnification image, a region to be observed at a high magnification in the image is displayed, that is, a visual field centered on a defect position 10 where high-magnification imaging is performed. By displaying the region 12 on the monitor 7 so as to overlap the image 9, it is possible to indicate to the user what region of the image is acquired in the high-magnification defect image.
Further, by simultaneously displaying a plurality of images among the images 8, 9, 9, and the image 11 in which the defect region or the high-magnification field-of-view region 12 is superimposed and displayed on the monitor 7, the user can operate. Images can be acquired while checking. A plurality of monitors 7 may be provided to display each of the images 8, 9, and 11 separately, or a combination of several images. A plurality of images may be displayed simultaneously or alternately on a single monitor. Also good.
Here, the image 8 and the image 9 are not necessarily images having the same pattern due to the positioning error of the stage 2, and an image shifted from each other may be obtained. In such a case, in the process of aligning both images and detecting the difference area, only the area that is always included in both images is effective. Therefore, the visual field range 12 that can be imaged at a high magnification needs to be within the visual field range of the image 9. That is, the first magnification and the second magnification are related to each other. Therefore, when the user designates one of the first magnification and the second magnification, a restriction may be provided on selection of the other magnification.

Next, FIG. 4 shows an extraction process procedure for background part erasure / defect part only for automatic inspection of a foreign object / defect area in image 11, and FIG. 5 shows an example of an image acquired by this extraction process procedure. Show.
Similar to the embodiment shown in FIG. 2, the images 8, 9, and 11 are acquired sequentially. Then, in the difference image 13 showing the difference area between the image 8 and the image 9, the area 12 that is the same as the imaging visual field area of the defect image 2 in the defect image 1 is enlarged at the same magnification as the defect image 2 by image processing. An image 14 is created.
Next, the mask image 14 and the image 11 are overlaid, an area corresponding to the difference area portion of the image 11 from the mask image 14 is extracted, and the difference area portion is erased from the image 11, whereby the image 11 It is possible to obtain an image 15 in which the background area is erased and only the defective area is extracted.
By detecting feature quantities such as the shape, brightness, and texture of the defect obtained from the extracted region, the defect can be analyzed without human intervention.

As a method for erasing the background from the image 11, as shown in FIG. 6, in the image 8 that is the reference image, an area having the same background as the imaging area 12 of the image 11 in the image 9 that is the defect image 1 is subjected to image processing. Thus, the reference enlarged image 16 enlarged to the same magnification as the image 11 may be created, and the difference between the image 11 and the image 16 may be extracted.
Further, as shown in FIG. 7, after the image 11 is captured, the stage 2 is moved so that an area having one chip, several chips, or the same pattern enters the field of view of the imaging device 5. Alternatively, the image 17 that is the reference image 2 may be acquired at the same magnification, and the difference between the image 11 and the image 17 may be extracted.
Here, when the visual field size of the image 11 and the movement accuracy of the stage 2 are close to each other, when the image 17 is picked up by moving the stage 2 as in the embodiment shown in FIG. It will shift.
In such a case, FIG. 8 shows an example of a procedure for acquiring a reference image corresponding to the image 11, and FIG. 9 shows an example of an image acquired by the procedure shown in FIG.

  Similar to the embodiment shown in FIG. 3, the images 8, 9, and 11 are acquired sequentially.

Next, the stage 2 is moved to the position where the image 8 is acquired, and the image 18 that is the reference image 2 is captured at the same magnification as the image 8.
At this time, the image 8 and the image 18 are misaligned due to the positioning error of the stage 2.
Next, an area corresponding to the imaging area 12 of the image 9 is cut out from the image 8 as a template and matched with the image 18 using the cut out template.

The matched position becomes the center of a region having the same background as the image 11.
Therefore, the image 19 that is the reference image 3 is captured at the same magnification as the image 11 with the matched position as the center.
By using such an imaging sequence, it is possible to reliably capture the image 19 corresponding to the image 11 even when the visual field size of the image 11 and the movement accuracy of the stage 2 are close to each other.
Further, in this imaging sequence, as a means for improving the tolerance that the imaging area of the image 19 is included in the area of the image 18, an offset from the image center of the defect position 10 and the image 9 in the image 9 is obtained in advance. In order to acquire 18, an offset may be added when moving the stage 2, and the movement amount of the stage 2 may be adjusted so that the position corresponding to the defect position becomes the center of the image 18.
Further, the images of the same magnification such as the image 8 and the image 9, the image 18 and the image 9, and the image 11 and the image 19 may be adjusted so that the brightness and the contrast are the same.
In the above imaging sequence, the image 9 as the defect image 1 is first imaged at the first magnification, and then the image 8 as the reference image 1 is imaged by moving the stage 2. The position 10 is calculated, and the image 19 of the reference image 3 is obtained by imaging at a high magnification, which is the second magnification, the stage 2 is moved to the defect position, and the image is captured at the first magnification to correspond to the defect image 1 After the image to be obtained is obtained, the defect position that is the center of the visual field of the high-magnification defect image may be calculated, and the image 11 that becomes the defect image 2 may be captured at the second magnification.
Next, in the case where a defect is inspected without using a reference image at a high magnification as described in FIGS. 2 and 3, and a plurality of defects are inspected continuously, FIG. 10 is used. I will explain.
In this case, after the image 8 corresponding to the defect to be inspected is continuously imaged within one chip or within several nearby chips in the reference image imaging step of the sequence described in FIG. 2 and FIG. The XY table 2 is moved so that the defective portion falls within the field of view of the imaging device 5, and an image 9 is obtained by imaging at the first magnification, the defect position 10 is calculated, and the image 11 is obtained by imaging at the second magnification. Is obtained continuously corresponding to a plurality of defects. By taking an image in this way, the amount of movement of the stage can be reduced and images can be collected efficiently.
Next, an example in which a plurality of defects are continuously inspected and a reference image at a high magnification is acquired will be described with reference to FIG.
First, the image XY that is the reference image 1 corresponding to the defect to be inspected is continuously imaged within one chip or within several chips in the vicinity, and then the XY stage 2 is set so that the defective portion enters the field of view of the imaging device 5. The image 9 is taken at the first magnification, the defect position 10 is calculated, and the image 11 is taken continuously.
Next, the stage 2 is moved to the position where the image 8 is acquired, the image 18 is captured at the same magnification as the image 8, and the region corresponding to the imaging region 12 of the image 9 is cut out from the image 8 as a template. The image 18 is matched using the template, and the operation of capturing the image 19 at the same magnification as the image 11 is performed continuously with the matched position as the center.
When the image 18 is acquired, the movement destination of the stage 2 does not necessarily have to be the same position as the image 8, and may be any position that has the same pattern as the background pattern of the image 9 in an arbitrary chip.
Next, in the embodiment shown in FIGS. 2 and 3, examples of procedures for reducing the number of times of obtaining the reference image are shown in FIGS.
When the image 8 is acquired by the method described in the embodiment shown in FIGS. 2 and 3, the image 8 is recorded, and at the same time, the field of view of the image 8 described in the chip coordinate system defined for each chip is recorded. Create an image map.
Then, when the coordinate position of the defect to be inspected given by another inspection apparatus is acquired, it is determined whether or not the reference area corresponding to the position data of the defect area is within the area stored in the reference image map. If it is within the area, a necessary area is read from the image data recorded without taking the image 8 and used as the image 8.
This reference image map may be created in the reference image at the first magnification, or may be created in the image at the second magnification taken at a higher magnification.
Thus, the number of times of acquiring the reference image can be reduced by recording and reusing the acquired image of the reference image. In particular, when reference images of all regions are acquired in the reference image map, the reference image acquisition process is not necessary, and the time required for image acquisition and detailed inspection can be greatly shortened.
Further, as shown in FIG. 14, in the reference image map, not only the area where the reference image is photographed but also the area having the same pattern as the reference image may be recorded as the acquired reference image area. Good.
For example, when a repetitive pattern image of one period or more is acquired in a region having a repetitive pattern, a reference image of an arbitrary region in the repetitive pattern can be created by combining the acquired images. Therefore, this is equivalent to acquiring reference images for all the repeated pattern areas.
Thus, by recording an area equivalent to the acquired reference image as an acquired area in the reference image map, the number of reference images to be acquired can be reduced, and the time required for the detailed inspection can be shortened. it can.
Further, reference images of all areas in the chip may be acquired in advance.
In addition, after a predetermined number of defects are inspected and a reference image map is created, a process may be performed in which a reference image is continuously captured for an area that has not been captured as a reference image, and all reference images are acquired. .
In this way, since it is guaranteed that all the reference images have been acquired at the time when the predetermined number of defects have been inspected, the defect inspection time after the predetermined number of defect inspections is completed. The time required can be guaranteed to the user.
FIG. 15 shows an embodiment in which the reference image data and the reference image map acquired by the above method are shared by a plurality of image collection devices.
In this embodiment, a plurality of image collection devices 20 and a server 21 (hereinafter referred to as database 21) are connected via a network. Then, the reference image data and the imaging area data on the reference image map are sent from each image collection device 20 to the database 21. The database 21 stores a reference image map and reference image data obtained by integrating data related to the reference images sent from a plurality of image collection devices 20.
And when inspecting a defect in each image collecting device 20, whether the reference image corresponding to the defective area is acquired is searched in the reference image map of the database 21, and if not acquired, the acquisition process is performed, Data relating to the reference image is sent to the database 21. If the reference image has been acquired, the corresponding reference image data is read from the database 21 and a detailed inspection is performed.

  In this way, reference image data can be collected efficiently. Further, by sharing the reference image data, the detailed inspection time can be shortened.

  Further, the collection of reference images may be performed by a single image collection device.

1 ... Sample 2 ... XY Stage 3 ... Computer
4. Control device 5. Imaging device 6. Display switching device
7... Monitor 8... Reference image at the first magnification 9... Defect image at the first magnification 10... Defect position 11 ... Defect image at the second magnification 12. Image field area 13 at a magnification of 2... Mask image 15 obtained by enlarging an image 14... 13 showing a difference between a reference image and a defect image at a first magnification to a size equivalent to the second magnification. 16... 8 Reference image enlarged to the same size as the second magnification 17... Reference image with the second magnification 18... Reference image with the first magnification obtained after 9 acquisition 19. Reference image by the second magnification 20... Image collecting device 21.

Claims (7)

An observation method for obtaining an observation image of one or more defects on a semiconductor wafer detected in advance by an inspection device,
A step of reading the deletion Ochiii location on said semiconductor wafer detected by the inspection device,
A first imaging step of capturing a reference image by imaging a chip different from a chip determined to have a defect at the defect position read out in the readout step at a first magnification ;
Moving said after a reference image captured by the first imaging step, before the position of the semiconductor wafer as a defect position of the semiconductor wafer detected by the inspection apparatus on the basis of Kiketsu Ochiii location falls within the imaging field of view And a process of
A second imaging step of imaging a first defect image including the defect of the semiconductor wafer at a first magnification after movement by the moving step ;
Identifying a defect position on the first defect image by comparing the first defect image captured by the first and the reference image captured by the imaging step the second imaging step ,
The method of observing a sample which is characterized in that it comprises the steps of imaging the second defect image with a high second magnification than the first magnification on the basis of the defect position specified by the specifying to step . A method for observing a sample according to claim 1, comprising:
And a step of generating a reference enlarged image obtained by enlarging the reference image taken in the first imaging step to the same magnification as the second defect image,
A sample observation method comprising a comparison step of comparing the second defect image and the reference enlarged image to extract a difference. A method for observing a sample according to claim 1 or 2 ,
Furthermore, after the step of capturing the second defect image, the step of moving the semiconductor wafer to the position where the reference image is captured at the first magnification,
The method of observing a sample, characterized in that it comprises the steps of imaging the reference image in the second magnification. An observation method for obtaining an observation image of one or more defects on a semiconductor wafer detected in advance by an inspection device,
Reading a defect position on the semiconductor wafer detected by the inspection device;
A first imaging step of obtaining a reference image by imaging a chip different from a chip in which a defect exists due to the defect position read out in the readout step;
A step of moving the position of the semiconductor wafer so that a defect position of the semiconductor wafer detected by the inspection apparatus based on the defect position is within an imaging field after taking a reference image in the first imaging step; ,
A second imaging step of imaging a first defect image including the defect of the semiconductor wafer at the same magnification as the first imaging step after the movement by the moving step;
Comparing the reference image imaged in the first imaging process with the first defect image imaged in the second imaging process to identify a defect position on the first defect image; ,
And a step of taking an enlarged image of the defect based on the defect position specified in the specifying step. A method for observing a sample according to claim 4,
And a step of generating a reference enlarged image obtained by enlarging the reference image captured in the first imaging step to the same magnification as the enlarged image of the defect,
A method for observing a sample, comprising a comparison step of extracting a difference by comparing the enlarged image of the defect and the enlarged reference image. A method for observing a sample according to claim 4 or 5,
Furthermore, after the step of capturing an enlarged image of the defect, the step of moving the semiconductor wafer to the position where the reference image is captured in the first imaging step;
  A method for observing a sample, comprising: taking a reference enlarged image. The sample observation method according to claim 1, wherein the imaging is performed with a scanning electron microscope.

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