WO2015040894A1

WO2015040894A1 - Defect viewing device and defect viewing method

Info

Publication number: WO2015040894A1
Application number: PCT/JP2014/064360
Authority: WO
Inventors: 高木　裕治; 祐子大谷
Original assignee: 株式会社日立ハイテクノロジーズ
Priority date: 2013-09-18
Filing date: 2014-05-30
Publication date: 2015-03-26
Also published as: JP2015059776A; TW201514479A

Abstract

　Although highly sensitive at detecting some types of defects, a conventional technique has reduced sensitivity to other types of defects. The conventional technique also has drawbacks in that mechanical switching of filters increases the amount of time taken to acquire a plurality of images under different detection conditions. The present invention is a defect viewing device provided with SEM and optical microscopes, and a control unit, the defect viewing device characterized in that the optical microscope is provided with: a radiating system for radiating light to a sample; and a detection system having a spatial filter, a spatial shape of which can be electrically controlled, and a distributed polarizer, a polarization state of which can be electrically controlled, for detecting a signal based on light from the sample irradiated by the radiating system; and the control unit generates a synchronization signal (202), controls and electrically switches the polarization state of the distributed polarizer and the spatial shape of the spatial filter on the basis of the generated synchronization signal (207, 206), and processes an image detected by the detection system in a plurality of combinations of polarization states of the distributed polarizer and spatial shapes of the spatial filter (123).

Description

Defect observation apparatus and method

The present invention relates to a defect observation apparatus and a defect observation method.

In semiconductor manufacturing processes, defect inspections such as foreign matter defects and pattern defects on semiconductor wafers are performed by defect position detection using a visual inspection device and defect observation using a defect observation device. Narrow down. SEM (Scanning Electron Microscope) is used as an observation apparatus because semiconductor patterns are miniaturized and fine defects also affect the yield. Since the appearance inspection device and the SEM observation device are different devices and there is a shift in the stage coordinates, only the defect position information detected by the appearance inspection device is used to locate the defect in the field of view of the SEM observation device. Difficult to do.

In particular, in patternless wafer inspection equipment, in order to increase the inspection throughput, the semiconductor substrate surface is scanned and irradiated with a larger laser beam spot size for illuminating the semiconductor substrate surface. The accuracy of the position coordinates obtained from the position of the laser beam spot that scans the substrate surface includes a large error component. If a defect is to be observed in detail using the SEM based on the position information of the defect including such a large error component, the defect is in the field of view of the SEM that is observed at a magnification much higher than that of the optical particle inspection apparatus. It becomes difficult to pay.

As a method for solving this, Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-106974) discloses a defect position detection using a dark field optical microscope mounted on an observation apparatus when observing a defect of a patternless wafer by SEM. A method of performing imaging of an SEM observation image using the detected position coordinates is disclosed. In addition, as a method for detecting a defect on a non-patterned wafer with high sensitivity, a method for detecting a defect position on a wafer with a distributed polarizing element and a spatial filter on the detection optical path of a dark field microscope is disclosed. .

JP 2011-106974 A

For defect observation of a patternless wafer by SEM, it is desired that redetection for defect positioning by an optical microscope can be performed with high sensitivity and high throughput for all defect types.

Patent Document 1 discloses a configuration of an electron microscope for defect observation equipped with a dark field optical system having a distributed polarizing element and a spatial filter on the pupil plane of a detection optical path.

However, Patent Document 1 discloses only the detection of a defect with a specific filter. For this reason, although a specific defect can be detected with high sensitivity, the sensitivity of other types of defects is reduced. There was a problem to do. In addition, when capturing images with different detection conditions by switching filters, there is no disclosure of a method of switching both the distributed polarization element and the spatial filter at the same time, and the disclosed mechanical filter switching method has a plurality of detections. There has been a problem that it takes time to acquire images under different conditions.

An object of the present invention is to redetect defects detected by a visual inspection apparatus with high sensitivity and high speed regardless of their types in detailed observation by SEM of defects detected by a semiconductor wafer visual inspection apparatus, and based on the redetection position. It is an object of the present invention to provide a defect detection apparatus and method, and a defect observation apparatus using the defect detection apparatus and method, which make it possible to reliably put a defect in the observation field of SEM.

In order to solve the above problems, for example, the configuration described in the claims is adopted.

The present application includes a plurality of means for solving the above-described problems. For example, the optical microscope includes an irradiation system for irradiating a sample with light and light from the sample irradiated by the irradiation system. And a detection system having a distributed polarization element capable of electrically controlling a polarization state and a spatial filter capable of electrically controlling a spatial shape, and the control unit generates a synchronization signal. , Based on the generated synchronization signal, the polarization state of the distributed polarization element and the spatial shape of the spatial filter are controlled and electrically switched, and a combination of the polarization state of the plurality of distributed polarization elements and the spatial shape of the spatial filter An image detected by the detection system is processed.

According to the present invention, it is possible to provide a defect observation apparatus and method capable of detecting a defect position with high sensitivity and high speed.

Configuration diagram of defect observation apparatus according to the present invention The figure which shows the detailed structure of the optical imaging system control circuit 121 of the defect observation apparatus which concerns on this invention. Flowchart of optical microscope image capturing step in defect observation method according to the present invention Timing chart of optical microscope image capturing in defect observation method according to the present invention The figure which shows the detailed structure of the optical microscope of the defect observation apparatus which concerns on this invention Flowchart of defect coordinate calculation step in the defect observation method according to the present invention. Overall flow chart of defect observation method according to the present invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

FIG. 1 is a configuration diagram of a defect observation apparatus according to the present invention.

The defect observation apparatus of the present embodiment is an apparatus for observing defects on a wafer that occur in a semiconductor device manufacturing process.

101 is a wafer to be inspected. Reference numeral 102 denotes an electron microscope (hereinafter referred to as SEM) for observing the wafer 1 in detail, and reference numeral 103 denotes an optical microscope that optically detects defects on the wafer 1 and acquires defect position information thereof. Reference numeral 104 denotes a stage on which the wafer 1 can be placed, which allows an arbitrary position of the wafer 1 to be moved within the field of view of the SEM 102 and the optical microscope 103. Reference numeral 105 denotes a vacuum chamber in which the SEM 102, the stage 104, and the objective lens 113 of the optical microscope 103 are housed.

The inside of the optical microscope 103 will be described. Reference numeral 110 denotes an illumination light source. The laser light emitted from the illumination light source 110 passes through the vacuum sealing window 111, is reflected by the mirror 112 that controls the illumination position, and is irradiated to an arbitrary position on the surface of the wafer 101. Reference numeral 113 denotes an objective lens for collecting scattered light reflected from the sample 101. The light passing through the objective lens 113 passes through the vacuum sealing window 114 and is imaged on the image sensor 116 by the imaging optical system 115. The imaging optical system 115 includes a distributed polarizing element 117 and a spatial filter 118 that can electrically control the polarization state and the spatial shape.

The control unit 106 includes a stage control circuit 119, an SEM imaging system control circuit 120, an optical system control circuit 121, an external input / output I / F 122, a CPU 123, and a memory 124. Each configuration from the stage control circuit 119 to the memory 124 is as follows. Connected to the bus 125, information can be input and output mutually. The stage control circuit 119 controls the stage 104, and the SEM imaging system control circuit 120 controls the SEM 102 and stores the detected image signal in the memory 124. The optical system control circuit 121 stores the image sensor 116 of the optical microscope 103, the distributed polarization element 117 and the spatial filter 118, and the image signal obtained from the image sensor 116 in the memory 124. The external input / output I / F 122 outputs display information to the terminal 107, information input from the terminal 107, information input / output to the storage device 108, and a defect inspection device or a higher-level management system (not shown) via the network 109. Input / output information. The image data stored in the memory 124 is processed by the CPU 123.

In the defect observation apparatus configured as described above, in particular, the optical microscope 103 redetects the position of the defect on the wafer 101 using the defect position information detected by the defect inspection apparatus (not shown) (hereinafter referred to as “defect inspection apparatus”). The control unit 106 has a function as position correction means for correcting the defect position information based on the defect position information detected by the optical microscope 103, and the SEM 102 is a control unit 106. Based on the defect position information corrected in step (b), the defect has a function of observing the defect. The image signal obtained from the optical microscope stored in the memory 124 is processed by the CPU 123 to detect the position of the defect, whereby the position information of the defect output from the defect inspection apparatus stored in the memory 124 is detected. Correct. The stage 104 is configured to be movable so that defects detected by the optical microscope 103 can be observed by the SEM 102.

FIG. 2 is a diagram showing a detailed configuration of the optical imaging system control circuit 121 of the defect observation apparatus according to the present invention.

The optical imaging system control circuit 121 includes a data I / F 201, a synchronization signal control circuit 202, an image information storage unit 204, a filter state control circuit 205, a distributed polarization element circuit 206, and a spatial filter control circuit 207, which are internal. It is connected to the bus 208. The data I / F 201 is connected to the internal bus 208 and the bus 125 in the control unit 106, and between the optical imaging system control circuit 121 and other processing units 119 to 124 in the control unit 106. Send and receive data. The synchronization signal generated by the synchronization signal generation circuit 203 in the synchronization signal control circuit 202 is transmitted through the synchronization signal control circuit 202 as a trigger signal for starting imaging of the image sensor 116 and image information stored in the image signal obtained from the image sensor 116. Used as a trigger signal for starting storage in the unit 204. The distributed polarizing element circuit 206 controls the distributed polarizing element 117, and the spatial filter control circuit 207 controls the spatial filter 118. The filter state control circuit 205 instructs the distributed polarizing element control circuit 206 and the spatial filter control circuit 207 to control the distribution polarizing element 117 and the spatial filter 118 in synchronization with the signal of the synchronization signal control circuit 202. .

The operation of the circuit and the optical system shown in FIG. 2 will be described with reference to the processing flow of FIG. 3 and the timing chart of FIG. Hereinafter, the filter state P refers to the polarization state of the distributed polarizing element 117 or data to be given to the distributed polarizing element control circuit 206 in order to control the distributed polarizing element 117 to that state, and the filter state S refers to space. The state of the spatial shape of the filter of the filter 118, or data given to the spatial filter control circuit 207 in order to control the spatial filter 118 to that state. Further, (P _k , S _k ) (k = 1,..., N) is a notation for clearly indicating that the filter states P _k and S _k are handled as one set, and the filter states (P _k , S _k ) indicates data in which the filter state P _k and the filter state S _k are set as one set.

FIG. 4 is a timing chart of optical microscope image capturing in the defect observation method according to the present invention.

The synchronization signal shown in FIG. 4 is a signal generated by the synchronization signal generation circuit 203 in FIG. 2, and the command signal is synchronized with the synchronization signal from the synchronization control circuit 202 to the filter state control circuit 205, image information storage. 3 and output to the image sensor 116 to control the processing steps shown in FIG. The polarization state of the distribution polarization element 117 shown in FIG. 4, shows the state of the distribution polarization element 117 at each time, and shows the state from P ₁ in P _3. 4, the spatial shape of the spatial filter 118, shows the state of the spatial filter 118 at each time is shown in S ₃ its state from S _1. Also, the operation of the image sensor 116 shown in FIG. 4 indicates the contents of the captured image at each time, the contents are indicated as images ₁ to _3, and the storage operation of the image information storage unit 204 is at each time The contents of the stored image are shown as images ₁ to ₃ . Image data captured by the image sensor 116 is transferred to and stored in the image information storage 204 in synchronization with the next synchronization signal after completion of imaging. The transfer of image data to the memory 124 shown in FIG. 4 indicates the transfer timing of image data from the image information storage unit 204 to the memory 124.
In FIG. 4, the polarization state of the distributed polarization element 117 and the spatial shape of the spatial filter 118 are changed at the falling edge of the synchronization signal, and imaging with the imaging element 118 is started at the same time, but the filter state control is performed at the rising edge of the synchronization signal. Even if the filter state (P _k , S _k ) is read from the circuit 205, the polarization state of the distributed polarization element 117 and the spatial shape of the spatial filter 118 are changed, and imaging with the image sensor 116 is started from the fall of the synchronization signal. Good. As a result, it can be expected that the imaging can be started after the state of the distributed polarizing element 117 and the filter of the spatial filter 118 is stabilized at the start of imaging by the imaging element 118.

FIG. 3 is a flowchart of an optical microscope image capturing step in the defect observation method according to the present invention.

First, the filter state control circuit 205 stores the filter states (P _k , S _k ) (k = 1,..., N) (S301). The filter states (P _k , S _k ) are stored in advance in the memory 124, the storage device 108, or a storage medium not shown in FIG. Let

Next, at time t ₁ shown in FIG. 4 (S 302), the filter state (P _k , S _k ) is read from the filter state control circuit 205, the filter state data P _k is sent to the distributed polarization element control circuit 206, and spatial filter control is performed. The filter state data _Sk is output to the circuit 207, and the polarization state of the distributed polarization element 117 and the spatial shape of the spatial filter 118 are simultaneously changed (S303). This change may be made before the start of imaging of the image 1 by the image sensor 116, and the state of the distributed polarization element 117 and the spatial filter 118 may or may not be changed simultaneously.

Similarly, at time t ₁ , imaging of the wafer 101 is started by the image sensor 116 by irradiation with the light source 110 (image ₁ ), and image data of the captured image ₁ is stored in the image information storage unit 204 by a command signal at time t _2. (S304).

S303 and S304 are repeated for the filter states (P _k , S _k ) (k = 1,..., N) (S305, S306). This process is repeated in synchronization with the command signal as shown in FIG. FIG. 4 shows an example where N = 3, but N is not limited to 3.

After storing the image data in the filter state (P _k , S _k ) (k = 1,..., N) in the image information storage unit 204, the image data is transferred from the image information storage unit 204 to the memory 124 (S307). ). In FIG. 4, the transfer timing is shown to start in synchronization with the next synchronization signal after the image data is stored in the image information storage unit 204, but the transfer start is after the image data is stored in the image information storage unit 204. Any time may be used as long as it is not shown in FIG. Also, the transfer time shown in FIG. 4 varies depending on the specifications of hardware such as the image data capacity to be transferred, the internal bus 208, the bus 125, the CPU 123 of the control unit 106, the memory 124, and the like.

Finally, the image data stored in the memory 124 is processed by the CPU 123, the defect position is specified (S308), and the defect position is written in the memory 124. At the time of defect imaging with the SEM, the CPU 123 reads out the specified defect coordinates (position information) from the memory 124, converts them into stage coordinates, and gives the stage coordinates to the stage control circuit 119, thereby correcting the corrected defect position. The stage can be moved to. . The processing content of S308 will be described later with reference to FIG.

The entire processing shown in FIG. 3 is referred to as S300, and is referred to in the processing flow shown in FIG.

It is disclosed in Patent Document 1 that the characteristics of the distributed polarizing element 117 and the spatial filter 118 need to be determined depending on the type of defect whose defect detection sensitivity is to be improved. For this reason, if an appropriate filter characteristic is set for the detection sensitivity of one type of defect, there is a problem that an optimal detection sensitivity cannot be obtained for another type of defect. In order to solve this problem, the present method and apparatus are biased toward a specific defect type by capturing an image by switching the characteristics of the distributed polarization element 117 and the spatial filter 118 and performing defect detection using a plurality of images. It is possible to obtain a sensitivity without any problems.

Defect type variations that must be considered from the perspective of the optical microscope are defects that should be considered when detecting with an optical microscope, not defect types in yield management, such as the types of defects expected to occur in the inspection process. This refers to variations in which the defect shape is roughly classified by shape such as concave or convex, and variations that are largely classified by the optical characteristics of the defect. For this reason, the number of filter states (P _k , S _k ) to be imaged can be limited.

As an example of the distribution deflection element 117 that can be electrically controlled, there is one using a liquid crystal whose birefringence changes depending on an applied voltage. By controlling the applied voltage of a liquid crystal element composed of a plurality of pixels to which different voltages can be applied for each pixel, a desired optical axis distribution can be provided within the filter surface. Further, as an electrically controllable spatial filter 118, there is a DMD (Digital Mirror Device) or the like. Although the configuration of the optical microscope in FIGS. 1 and 2 is simplified for the sake of explanation, the DMD used as a spatial filter is an optical element that reflects light and cannot transmit light. For this reason, it is necessary to devise an optical path as shown in FIG.

FIG. 5 is a diagram showing a detailed configuration of the optical microscope of the defect observation apparatus according to the present invention.

In FIG. 5, an imaging optical system 115 includes a lens 502 that forms an image on the pupil plane 501 of the objective lens 113, a mirror 503 that reflects an optical path to a spatial filter 118 that is a DMD, a distributed polarization element 119, and a lens that forms an image. 504. A distributed polarizing element 119 is placed at a position 505 where the pupil plane 501 of the objective lens 113 forms an image. Since the spatial filter 118 only needs to have a spatial resolution required by the spatial shape to be controlled, the spatial filter 118 can be placed at a position where the pupil plane 501 of the objective lens 113 is defocused on the optical path. As long as the effect on the defect detection sensitivity obtained by the spatial filter 118 and the distributed polarizing element 119 is not hindered, the spatial filter 118 is positioned at the position where the pupil plane forms an image 505 and the distributed polarizing element 119 is positioned where the pupil plane forms an image. It may be placed near the optical path 505 or both the spatial filter 118 and the distributed polarizing element 119 may be placed near the position 505 where the pupil plane is imaged on the optical path.

FIG. 6 is a flowchart of the defect coordinate calculation step in the defect observation method according to the present invention.

FIG. 6 shows a processing method for specifying a defect position using N images captured in a filter state (P _k , S _k ) (k = 1,..., N). FIG. 6 shows details of the processing in S308 of FIG. Therefore, all processing in FIG. 6 is performed by the CPU 123.

A pixel average gray value (average value _k ) of the image _k and a value (3σ _k ) three times the standard deviation are _obtained (S602).
A normalized image _k is generated using the obtained average value _k and 3σ _k (S603). Α and β in the calculation formula shown in S603 are coefficients for keeping the calculation result in a range that can be taken by the pixel value of the normalized image _k , and may be arbitrarily determined.

S602 and S603 are repeated for the number N of images, and a normalized image _k (k = 1,..., N) is obtained (S605). In S606, the maximum pixel value at the same coordinate (i, j) of the N normalized images _k is set as the pixel value of the integrated image (i, j). K specifying the filter state giving the maximum value is stored in the memory 124 as max_k. In the generation of the SEM observation image, for example, the SEM observation image is generated so that the property of the defect corresponding to the filter, for example, the property such as the unevenness, is manifested in the SEM observation image by recording the filter state in which the defect is most apparent. When the observation image is generated using the secondary electron image and the reflected electron image detected in step 1, the mixing ratio of each image can be changed for each defect.

Next, the integrated image (i, j) is binarized with a predetermined defect detection threshold TH to obtain a binary image (S607).

The label area having the maximum area is detected from the label image obtained by labeling the binary image (i, j), and the center of gravity of the maximum area label is set as the defect coordinate (S608, S609).

The defect position detected as the last detected image coordinate is converted into stage coordinates (S610).

FIG. 7 is an overall flowchart of the defect observation method according to the present invention. The procedure for collecting SEM defect images using the corrected defect coordinates is shown in a flowchart.

First, a wafer to be observed is loaded on the stage 104 shown in FIG. 1 (S701).

Next, the defect coordinate data of the defect detected in advance by the inspection apparatus is read into the memory 124 via the external input / output I / F 122 of the overall control unit 106 (S702). Select (S703). The defect selection may be executed by the CPU 123 using a preset program, or may be selected by the operator via the terminal 107.

Next, wafer alignment is performed (S704). This is because when the stage 104 is moved based on the position of the defect coordinates described in the coordinates on the wafer, the position of the target defect coordinates is in the center of the field of view of the SEM 102 and the field of view of the optical microscope 103. Therefore, the wafer coordinates and the stage coordinates are associated with each other using positioning marks (alignment marks) whose coordinates on the wafer are known. This association result is stored in the memory 124 as alignment information.

Next, defect positions are corrected for defects 1 to M selected as observation targets (S705, S708, S709).

First, the defect m is moved to the field of view of the optical microscope 103 (S706). In this movement, the CPU 123 calculates the stage coordinates corresponding to the defect m from the defect coordinate data stored in the memory 124 and the alignment information, thereby driving the stage 104 via the stage control circuit 119. Done.

After the stage movement is completed, the position of the defect _m is specified by the process shown in FIG. 3 (S300), and the position of the specified defect is stored in the memory 124 as the corrected defect position _m (S707).

The above sequence of S706, S300, and S707 is performed on the defect m (m = 1,..., M). Some inspection apparatuses output not only the detected defect position coordinates but also information on the feature of the defect. For example, if the defect feature information indicates beforehand whether the defect is convex or concave, the filter state may be changed and set for each defect accordingly. In order to realize this, the filter state corresponding to the defect feature information is stored in the memory 124 as a table in advance. When the defect coordinate data of the defect detected by the above-described inspection apparatus is read into the memory 124, the defect feature information is also read, the defect information is read for each defect by the CPU 123, and the table stored in the memory 124 is stored. The filter state may be determined by collating with the information, and the filter state information may be sent to the filter state control circuit 205. On the other hand, if the applied filter states (P _k , S _k ) (k = 1,..., N) are the same for all defects, the process S301 in S300 shown in FIG. 3 is performed before S705. It doesn't matter.

All defects m (m = 1, ..., M) after obtaining the corrected defect position _m of, reads out the correction defect position _m from the memory 124, after converting the position information on the stage coordinate optionally, stage control By supplying to the circuit 119, the defect _m is sequentially moved to the field of view of the SEM 102 (S711), and an SEM image of the defect _m is captured (S712, S713, S714). When capturing the SEM image of the defect _m , after capturing the SEM images of all the defects in the filter state stored in the memory 124, the wafer is unloaded (S715), and the process ends.

As described above, it becomes possible to detect the defect position with high sensitivity and high speed for all defect types detected by the inspection apparatus. By installing the optical detection system described above in the SEM defect observation apparatus, defect detection by optical detection is possible. By performing the SEM observation at the position, it becomes possible to reliably put the defect in the observation field of the SEM, and the success rate of the automatic imaging of the SEM observation image of the defect detected by the inspection apparatus is improved. The throughput of automatic imaging is also improved.

DESCRIPTION OF SYMBOLS 101 ... Wafer, 102 ... SEM, 103 ... Optical microscope, 104 ... Stage, 105 ... Vacuum chamber, 106 ... Control part, 107 ... Terminal, 108 ... Storage device, 109 ... Network, 110 ... Light source, 111 ... Vacuum sealing window , 112 ... mirror, 113 ... objective lens, 114 ... empty sealing window, 115 ... imaging optical system, 116 ... imaging element, 117 ... distributed polarization element, 118 ... spatial filter, 119 ... stage control circuit, 120 ... SEM imaging System control circuit 121... Optical imaging system control circuit 122. External input / output I / F, 123 CPU, 124 Memory, 125 Bus, 201 Data I / F 202 Synchronization control circuit 203 Synchronization signal Generator circuit 204 image information storage unit 205 filter state control circuit 206 distributed polarization element control circuit 207 spatial filter control circuit 08 ... internal bus

Claims

A defect observation apparatus comprising an SEM, an optical microscope, and a control unit,
The optical microscope includes an irradiation system for irradiating a sample with light, and a distributed polarizing element capable of detecting a signal based on the light from the sample irradiated by the irradiation system and electrically controlling a polarization state. A detection system having a spatial filter capable of controlling a spatial shape,
The control unit generates a synchronization signal (202), controls the polarization state of the distributed polarization element and the spatial shape of the spatial filter based on the generated synchronization signal and electrically switches (207, 206), a plurality of the A defect observation apparatus characterized in that an image detected by the detection system in a combination of a polarization state of a distributed polarizing element and a spatial shape of the spatial filter is processed (123).
The defect observation apparatus according to claim 1,
Defect observation characterized by detecting a position of a defect by processing an image detected by the detection system in a combination of a polarization state of a plurality of distributed polarizing elements and a spatial shape of the spatial filter in the control unit apparatus.
The defect observation apparatus according to claim 1,
The control unit generates a continuous synchronization signal at a constant time interval, in a combination of control of the distributed polarizing element and the spatial filter, a polarization state of the plurality of distributed polarizing elements, and a spatial shape of the spatial filter. A defect observation apparatus characterized in that the detection of an image detected by the detection system is continuously performed on the synchronization signal.
The defect observation apparatus according to claim 1,
The control unit changes a mixing ratio of a secondary electron image and a reflected electron image detected by the SEM based on a combination of a polarization state of the plurality of distributed polarizing elements and a spatial shape of the spatial filter. Feature defect observation device.
The defect observation apparatus according to claim 1,
The defect observation apparatus, wherein the distributed polarizing element is a liquid crystal filter, and the spatial filter is a digital mirror device.
The defect observation apparatus according to claim 1,
The defect observing apparatus, wherein the controller determines a state of the spatial filter based on defect information of the defect apparatus.
A defect observation method using a defect observation apparatus including an SEM, an optical microscope, and a control unit,
An irradiation step of irradiating the sample with light;
A detection step having a distributed polarization element capable of electrically controlling a polarization state and a spatial filter capable of electrically controlling a spatial shape, detecting a signal based on light from the sample irradiated in the irradiation step;
A synchronization signal is generated (202), and the polarization state of the distributed polarization element and the spatial shape of the spatial filter are controlled and electrically switched based on the generated synchronization signal (207, 206), and the polarization of the plurality of distribution polarization elements A defect observation method comprising a control step (123) of processing an image detected by the detection system in a combination of a state and a spatial shape of the spatial filter.
The defect observation method according to claim 7,
In the control step, a defect position is detected by processing an image detected by the detection step in a combination of a polarization state of the plurality of distributed polarizing elements and a spatial shape of the spatial filter. Method.
The defect observation method according to claim 7,
In the control step, a continuous synchronization signal is generated at a constant time interval, and in the combination of the control of the distributed polarizing element and the spatial filter, the polarization state of the plurality of distributed polarizing elements, and the spatial shape of the spatial filter A defect observing method, wherein the detection of the image detected by the detection step is continuously performed on the synchronization signal.
The defect observation method according to claim 7,
In the control step, the mixing ratio of the secondary electron image and the reflected electron image detected by the SEM is changed based on a combination of a polarization state of the plurality of distributed polarizing elements and a spatial shape of the spatial filter. A feature defect observation method.
The defect observation method according to claim 7,
The defect observing method, wherein the distributed polarizing element is a liquid crystal filter, and the spatial filter is a digital mirror device.
The defect observation method according to claim 7,
In the control step, the state of the spatial filter is determined based on defect information of a defect device.