JP5623590B2 - Electron microscope equipment - Google Patents

Description

  The present invention relates to an electron microscope apparatus capable of observing a scanning electron image and an optical image of a sample, and more particularly to an electron microscope apparatus capable of simultaneously observing an optical image during electronic scanning.

  A scanning electron microscope (SEM) scans an electron beam on a sample, detects electrons emitted by irradiation of the electron beam, and acquires a scanning electron image of the property of the sample surface.

  On the other hand, the angle of view of the electron beam is very small, and it is extremely difficult to irradiate a specific position with the electron beam unless the irradiation position is known in advance.

  For this reason, the electron microscope apparatus has an optical microscope with a lower magnification than the electron microscope. First, the sample is illuminated with illumination light (white light), the sample is observed with the optical microscope, the irradiation position is specified, and the next The electron microscope is switched to an electron microscope, and an irradiation position is scanned with an electron beam for observation.

  When obtaining a scanning electron image, electrons emitted from a sample are made incident on the phosphor, light emitted from the phosphor is converted into an electric signal by a photoelectric conversion element, and a scanning electron image is acquired based on the electric signal. . An optical image using an optical microscope is also obtained by receiving light reflected from a sample by a photoelectric element for the optical microscope and converting it into an electrical signal, and an optical image is acquired based on the electrical signal.

  However, the energy level of the electrons obtained by scanning the electron beam and the light reflected from the sample are significantly different. When the reflected light from the sample enters the photoelectric element that detects the electron beam, the photoelectric element is saturated. In other words, the S / N becomes extremely small, and the electron beam cannot be detected.

  For this reason, switching between the case of observation with an optical microscope and the case of observation with an electron microscope has been completely switched. Conventionally, in the state of observation with an optical microscope, observation with an electron microscope is not possible, and observation with an electron microscope is also possible. In this state, the structure is such that it is not observed with an optical microscope.

  For example, the optical microscope and the electron microscope are separated, the optical axis of the optical microscope and the optical axis of the electron microscope are provided in a known relationship, and the table holding the sample moves between the optical microscope and the electron microscope. As a result, the observation position of the optical image and the observation position of the scanning electron image are associated with each other.

  For this reason, the conventional electron microscope has a problem that the structure is complicated and the scanning electron image and the optical image cannot be observed simultaneously.

  In addition, there exists what is shown by patent document 1 as an electron microscope which enabled simultaneous observation of a scanning electron image and an optical image.

  In the technique disclosed in Patent Document 1, the optical system of the electron microscope and the optical system of the optical microscope are set to the same optical axis, and the illumination light and the electron beam are simultaneously irradiated. The signal is removed as a direct current component, and a signal containing only electrons is extracted.

  However, as described above, since the direct current component due to the illumination light is significantly larger than the signal component, it is extremely difficult to realize.

JP-A-4-280053

  In view of such circumstances, the present invention enables simultaneous observation of a scanning electron image and an optical image, and enables simultaneous observation and work other than scanning electron image observation and scanning electron image observation. A simple electron microscope apparatus is provided.

The present invention includes a scanning unit that scans an electron beam and an electron detector that detects electrons emitted from a sample scanned with the electron beam, and obtains a scanning electron image based on a detection result from the electron detector. And a foreign substance detection device for detecting foreign matter by irradiating the sample surface with inspection light and detecting scattered light from the foreign substance, and the electron detector includes a phosphor layer for electron / light conversion, A wavelength filter limited to transmit all or substantially all of the wavelength band of fluorescence from the phosphor layer, and a wavelength detection element that receives the fluorescence transmitted through the wavelength filter and performs optical / electrical conversion. The inspection light relates to an electron microscope apparatus set so as to have a wavelength outside the transmission wavelength band of the wavelength filter.

  The present invention also includes scanning means for scanning an electron beam and an electron detector for detecting electrons emitted from a sample scanned with the electron beam, and obtains a scanning electron image based on the detection result from the electron detector. A scanning electron microscope; and an interferometer that irradiates the sample surface with interference light and detects the height position of the sample using the interference light reflection from the sample surface. A phosphor layer for light conversion, a wavelength filter restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and receiving the fluorescence transmitted through the wavelength filter, The present invention relates to an electron microscope apparatus having a wavelength detecting element for electrical conversion, wherein the interference light is set to have a wavelength deviating from a transmission wavelength band of the wavelength filter.

The present invention also includes scanning means for scanning an electron beam and an electron detector for detecting electrons emitted from a sample scanned with the electron beam, and obtains a scanning electron image based on the detection result from the electron detector. A scanning electron microscope, an optical microscope that irradiates the sample with illumination light and receives reflected light from the sample to obtain an optical image, and irradiates the sample surface with inspection light to detect scattered light from foreign matter. A foreign matter detection device that detects foreign matter, and an interferometer that irradiates the sample surface with interference light and detects the height position of the sample using the interference light reflection from the sample surface, The electron detector includes a phosphor layer that performs electron / light conversion, a wavelength filter that is restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and the fluorescence that has passed through the wavelength filter. Wavelength detector that receives light and converts light to electricity The illumination light, the inspection light, and the interference light have wavelengths that are out of the transmission wavelength band of the wavelength filter, and the illumination light, the inspection light, and the interference light have different wavelength bands. The present invention relates to an electron microscope apparatus set to (1).

  According to the present invention, the illumination light is white light, and a wavelength filter that transmits a wavelength band outside the transmission wavelength band of the wavelength filter is detachably provided on the optical path of the illumination light, and the scanning electron At the time of scanning electron image observation with a microscope, the wavelength filter is inserted to enable simultaneous observation with an optical image. When the scanning electron image observation is not performed, the wavelength filter is removed to separate from the scanning electron image observation. Thus, the present invention relates to an electron microscope apparatus that enables observation of an optical image.

  The present invention also relates to an electron microscope apparatus capable of inserting and removing the wavelength filter restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted.

According to the present invention, the scanning means for scanning the electron beam and the electron detector for detecting electrons emitted from the sample scanned with the electron beam are provided, and the scanning electron image is obtained based on the detection result from the electron detector. A scanning electron microscope to obtain, and a foreign substance detection device that irradiates the sample surface with inspection light and detects scattered light from the foreign substance to detect the foreign substance, and the electron detector is a phosphor that performs electron / photo conversion. Layer, a wavelength filter restricted so that all or almost all of the wavelength band of the fluorescence from the phosphor layer is transmitted, and a wavelength detection element that receives the fluorescence transmitted through the wavelength filter and performs optical / electrical conversion The inspection light is set to have a wavelength outside the transmission wavelength band of the wavelength filter, so that the influence of the inspection light on scanning electron image observation is eliminated, observation of the scanning electron image and foreign object detection, Foreign object observation at the same time Also it is not necessary to perform the foreign object detection by obtaining a foreign matter detecting system of a scanning electron image by a scanning electron microscope by mechanical separation, the structure can be simplified.

  Further, according to the present invention, the scanning means for scanning the electron beam and the electron detector for detecting the electrons emitted from the sample scanned with the electron beam are provided, and the scanning electron image is based on the detection result from the electron detector. And an interferometer that irradiates the sample surface with interference light and detects the height position of the sample using the interference light reflection from the sample surface, and the electron detector Is a phosphor layer that performs electron / light conversion, a wavelength filter that is restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and receives the fluorescence that has passed through the wavelength filter, Since it has a wavelength detecting element for optical / electrical conversion, and the interference light is set to have a wavelength outside the transmission wavelength band of the wavelength filter, the influence of the interference light on the scanning electron image observation is eliminated, and scanning is performed. Electron image observation and sample Is performed measurement and simultaneously, also a height measurement of the sample and obtaining a scanning electron image by a scanning electron microscope according to the interferometer need not be performed by mechanically separated, the structure can be simplified.

Further, according to the present invention, the scanning means for scanning the electron beam and the electron detector for detecting the electrons emitted from the sample scanned with the electron beam are provided, and the scanning electron image is based on the detection result from the electron detector. a scanning electron microscope to obtain an optical microscope to obtain an optical image by receiving the reflected light from the sample by irradiating the illumination light to the sample, is irradiated with inspection light on the surface of the sample, scattered light from the foreign matter A foreign matter detection device for detecting foreign matter and detecting a foreign matter, and an interferometer for irradiating the sample surface with interference light and detecting the height position of the sample using the interference light reflection from the sample surface. The electron detector includes a phosphor layer for electron / light conversion, a wavelength filter restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and the wavelength filter transmitted through the wavelength filter. Wavelength detector that receives fluorescence and converts light to electricity The illumination light, the inspection light, and the interference light have wavelengths outside the transmission wavelength band of the wavelength filter, and the illumination light, the inspection light, and the interference light have different wavelength bands. Therefore, illumination light, inspection light, and interference light have no effect on scanning electron image observation. Scanning electron image observation, optical image observation, foreign object detection, foreign object observation, and sample height measurement Furthermore, it is necessary to separate the acquisition of the scanning electron image by the scanning electron microscope and the acquisition of the optical image by the optical microscope, the detection of the foreign material by the foreign material detection device, and the measurement of the sample height by the interferometer. And the structure can be simplified.

  According to the invention, the illumination light is white light, and a wavelength filter that transmits a wavelength band that is out of the transmission wavelength band of the wavelength filter is detachably provided on the optical path of the illumination light. When observing a scanning electron image with a scanning electron microscope, the wavelength filter is inserted to enable simultaneous observation with an optical image. When the scanning electron image observation is not performed, the wavelength filter is removed, and the scanning electron image observation is performed. Since the optical image can be observed separately, it is possible to obtain a full-color optical image of the sample.

  Further, according to the present invention, since the wavelength filter restricted to transmit all or almost all of the wavelength band of fluorescence from the phosphor layer can be inserted and removed, it is possible to perform illumination when simultaneous observation is unnecessary. Uses an electron microscope device with the light turned off, and exhibits superior effects such as higher sensitivity observation.

It is a schematic block diagram of the electron microscope apparatus by which this invention is implemented. It is the schematic block diagram which looked at this electron microscope apparatus from the other direction. It is explanatory drawing which shows an example of the electron detector used for this electron microscope apparatus. (A) is a diagram showing the relationship between the sensitivity region of the wavelength detection element and the wavelength band of the fluorescence emitted from the phosphor layer, and (B) is a diagram showing the transmission wavelength band of the wavelength filter incorporated in the electron detector. It is. It is a diagram which shows the wavelength range | band of the light-emission fluorescence at the time of using another fluorescent substance layer.

Embodiments of the present invention will be described below with reference to the drawings.

  First, the outline of the electron microscope apparatus 1 according to the present invention will be described with reference to FIGS.

  The electron microscope apparatus 1 includes a scanning electron microscope 2, an optical microscope 3, an interferometer 4, a control unit 5 that controls the operation of the scanning electron microscope 2, the optical microscope 3, and the interferometer 4, A measurement object (sample) 8 is installed at a point where the optical axis 6 of the optical microscope 3 and the optical axis 7 of the scanning electron microscope 2 intersect, and the measurement object 8 can move in two directions of XY. 9 is mounted.

  The optical axis 7 of the scanning electron microscope 2 is inclined at a predetermined angle (for example, 60 °) with respect to the optical axis 6 of the optical microscope 3, and the point where the optical axis 6 and the optical axis 7 intersect is the measurement point. This is the observation point of the object 8. An electron beam is irradiated onto the measurement object 8 along the optical axis 7 and a predetermined range is scanned by the electron beam scanning means 10. By irradiating the electron beam, the electrons 11 emitted from the measurement object 8 are detected by the electron detector 12. The inspection stage 9 moves in two directions XY in synchronism with the irradiation of the electron beam, and the electron beam scans the required range of the measurement object 8.

  The detection result of the electron detector 12 is sent to the control unit 5, and a scanning electron image is created in the control unit 5 based on the detection result.

  An LED 13 that emits illumination light (white light), a first half mirror 14, a second half mirror 15, and an objective lens 16 are disposed on the optical axis 6, and further between the LED 13 and the first half mirror 14. A wavelength filter 40 (described later) is provided to be detachable with respect to the optical axis 6.

  The light emission of the LED 13 is controlled by the light emission drive unit 17. The illumination light emitted from the LED 13 is applied to the measurement object 8 through the first half mirror 14, the second half mirror 15, and the objective lens 16, and the illumination light reflected by the measurement object 8 is the second light. The light passes through the half mirror 15, is reflected by the first half mirror 14, and is received by the observation CCD 18.

  The interferometer 4 has an optical axis 19 that is deflected by the second half mirror 15 and reaches the measurement object 8. A third half mirror 21 is disposed on the optical axis 19, a measurement CCD 22 is disposed on one side of the third half mirror 21, and a reference mirror 23 is disposed on the other side.

  Single-wavelength light for interference is emitted from the measurement light source 24 onto the optical axis 19, and a part of the single-wavelength light is transmitted through the third half mirror 21, reflected by the second half mirror 15, and the objective. The measurement object 8 is irradiated through the lens 16. The single wavelength light reflected by the measurement object 8 is received by the measurement CCD 22 through the second half mirror 15 and the third half mirror 21. Further, the remaining portion of the single wavelength light reflected by the third half mirror 21 is reflected by the reference mirror 23, passes through the third half mirror 21, and then is received by the measurement CCD 22. The measurement CCD 22 receives the reflected light from the measuring object 8 and the reflected light from the reference mirror 23, and measures the position of the measuring object 8 in the height direction by interference of both reflected lights.

  Three-dimensional position information of the observation point is obtained from the XY position of the observation point of the measurement object 8 and the position in the height direction obtained by the interferometer 4.

  In addition, a foreign matter detection device 25 for detecting foreign matter on the surface of the measurement object 8 is provided.

  The foreign matter detection device 25 includes a foreign matter detection light source 26 that emits inspection light for detecting foreign matter and a scattered light detector 27 that detects scattered light reflected by the foreign matter. The axis 28 enters the surface of the measuring object 8 from a direction different from the optical axis 7 of the scanning electron microscope 2. Further, the optical axis 29 of the scattered light detector 27 is in a direction perpendicular to the paper surface of FIG. 2 so as to easily receive the scattered light. That is, the plane including the irradiation optical axis 28 and the optical axis 6 is orthogonal to the plane including the optical axis 29 and the optical axis 6. Note that FIG. 2 shows the irradiation optical axis 28 and the optical axis 29 in the same plane for easy understanding.

  When the surface of the measuring object 8 is irradiated with inspection light and there is a foreign object on the surface of the measuring object 8, the inspection light is scattered by the foreign object, and the scattered light detector 27 detects the scattered light. Although the size of the foreign matter that can be detected varies depending on the wavelength of the inspection light used, even when red light is used, it is possible to detect a foreign matter having a size of submicron that is difficult to observe with the optical microscope 3. . Further, the field angle of the inspection light is larger than that of the electron beam, and it is easier to specify the irradiation position of the inspection light and find the target inspection site than the electron beam.

  Next, the electron detector 12 will be described with reference to FIG.

  A phosphor layer 32 is formed on a transparent plate 31 such as a glass substrate to constitute an electron / light conversion member (scintillator) 33. The electron / light conversion member 33 includes a wavelength filter 34, a light guide 35, and a wavelength detection element 36. Are sequentially arranged and further covered with a light shielding cover 37 to be integrated to constitute the electron detector 12.

  When the electrons 11 enter the phosphor layer 32, the phosphor layer 32 emits a wavelength (fluorescence) in a predetermined amount region. The fluorescent light passes through the wavelength filter 34 and further reaches the wavelength detection element 36 through the light guide 35. The wavelength detection element 36 converts fluorescence into an electrical signal. Therefore, the electron detector 12 performs electron / light / electric conversion, and emits an electric signal when the electron 11 is incident.

  In the present invention, light that the electron detector 12 converts and detects the electrons 11, illumination light that the LED 13 irradiates, single wavelength light that the measurement light source 24 irradiates, and inspection that the foreign matter detection light source 26 irradiates The light is made into light of different wavelength bands, each is separated by wavelength, and the separated wavelengths are selected and detected so that they can be observed simultaneously by a plurality of optical systems.

  Hereinafter, the electron detector 12 will be further described with reference to FIGS.

  In FIG. 4A, a curve A indicates a wavelength band emitted from the phosphor layer 32, and a curve B indicates a wavelength band detected by the wavelength detection element 36. As shown in the figure, the wavelength band of the curve B is wider than the wavelength band of the curve A, and the curve A, that is, the phosphor layer 32 emits the wavelength band reaching the wavelength detecting element 36. Even if it is limited to the fluorescence wavelength band, there is no problem in sensitivity.

  In FIG. 4B, curve C shows the wavelength transmission characteristic of the wavelength filter 34. The wavelength filter 34 has a transmission wavelength band W. The transmission wavelength band W includes most of the fluorescence wavelength band, and the transmission of the wavelength is substantially limited to the fluorescence wavelength band. For example, it transmits a wavelength band of 300 nm to 600 nm. When the wavelength filter 34 restricts the transmission band of the fluorescence wavelength, it is set so that the amount of transmitted fluorescence is 90% to 95% or more.

  Accordingly, if the illumination light emitted from the LED 13, the interference single wavelength light emitted from the measurement light source 24, and the wavelength of the inspection light emitted from the foreign object detection light source 26 are out of the transmission wavelength band W, By scanning the electron beam and observing the scanning electron image, observation with another illumination light can be performed. At this time, the transmittance with which the illumination light and the light from the measurement light source 24 pass through the wavelength filter 34 is preferably 0.001% or less.

  For example, if the wavelength of the inspection light emitted by the foreign object detection light source 26 is indicated by a wavelength D in FIG. 4B, the inspection light is blocked by the wavelength filter 34 and reaches the wavelength detection element 36. do not do. That is, the scanning electronic image can be observed while detecting or observing the foreign matter on the surface of the measurement object 8 by the foreign matter detection device 25.

  In the interferometer 4, it is not necessary to visually observe the image obtained by the CCD 22 for measurement, so that the selectable wavelength band is widened, and a wavelength other than the transmission wavelength band W and the wavelength D is selected. Easy to do.

  Next, FIG. 5 shows another example of the wavelength band of the fluorescence emitted by the phosphor layer 32. In the wavelength band indicated by the curve E in FIG. 5, the fluorescence peak is concentrated at a wavelength of 400 nm. The spread of the wavelength band is also narrower than that shown by the curve A in FIG. The wavelength of visible light is said to be 380 nm to 780 nm. In the phosphor layer 32 having the curve E, the transmission wavelength band W of the wavelength filter 34 is limited to about 380 nm to 530 nm, so that the fluorescence wavelength band By limiting the transmission wavelength band W to about 380 nm to 530 nm, it is possible to use visible light in a wavelength band of 530 nm to 780 nm, that is, visible light excluding blue light.

  Further, if a part of the wavelength band of 530 nm to 780 nm is assigned to the illumination light of the optical microscope 3 and the other wavelength band is assigned to the inspection light of the foreign object detection device 25, an optical image by the optical microscope 3 is obtained. Observation, foreign object detection by the foreign object detection device 25, and observation of a scanning electron image by the scanning electron microscope 2 can be performed simultaneously. Each wavelength band described above is an exemplification, and the present invention is not limited to each wavelength band.

  The LED 13 may be selected to emit light having a wavelength band outside the transmission wavelength band W, or the light emitted from the LED 13 is white light, and the wavelength filter 40 is provided. You may restrict | limit to the wavelength band out of the transmission wavelength band W.

  In this case, when the wavelength filter 40 can be inserted into and removed from the optical axis 6 and an optical image is observed with the optical microscope 3 alone, if the wavelength filter 40 is removed, a full-color optical image is observed. can do.

  As described above, the convenience of the electron microscope apparatus 1 is further improved by separating the wavelength band detected by the electron detector 12, the wavelength band of the illumination light of the optical microscope 3, and the wavelength band of the inspection light. .

  That is, first, an optical image of the measurement object 8 is observed with the optical microscope 3, and a predetermined observation site is specified. While observing the optical image, the foreign object detection device 25 irradiates the inspection light, and the irradiation position is further limited by the scattered light. Next, an electron beam is irradiated to observe a scanning electron image of the observation site.

  Since the angle of view of the optical system of the optical microscope 3, the angle of view of the inspection light, and the angle of view of the electron beam are sequentially reduced, it is easy to specify the irradiation position of the electron beam. In addition, since the observation with the optical microscope 3 and the observation with the foreign object detection device 25 can be performed at the same time, correction and change at the time of specifying the observation site can be easily performed at any time.

  Further, the wavelength filter 34 can be inserted and removed. Thereby, when simultaneous observation is unnecessary, the electron microscope apparatus 1 is used in a state in which the illumination light is extinguished, so that observation with higher sensitivity is possible. This is effective when it is desired to improve the S / N ratio.

  When foreign matter is detected by the foreign matter detection device 25, foreign matter inspection such as obtaining physical properties of the foreign matter by spectrum analysis or the like from information obtained by the electronic detector 12 may be performed.

DESCRIPTION OF SYMBOLS 1 Electron microscope apparatus 2 Scanning electron microscope 3 Optical microscope 4 Interferometer 5 Control part 8 Measuring object 11 Electron 12 Electron detector 13 LED
24 Light Source for Measurement 25 Foreign Object Detection Device 26 Light Source for Foreign Object Detection 27 Scattered Light Detector

Claims (5)

A scanning means for scanning an electron beam; and a scanning electron microscope having an electron detector for detecting electrons emitted from a sample scanned with the electron beam, and obtaining a scanning electron image based on a detection result from the electron detector; Irradiating the sample surface with inspection light, and detecting the scattered light from the foreign matter to detect the foreign matter, and a foreign matter detection device,
The electron detector includes a phosphor layer for electron / light conversion, a wavelength filter restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and the fluorescence transmitted through the wavelength filter. A wavelength detecting element that receives light and converts light / electricity,
The inspection light is set to have a wavelength outside the transmission wavelength band of the wavelength filter received by the wavelength detection element in order to acquire the scanning electron image,
An electron microscope apparatus configured to be capable of observing with the scanning electron image simultaneously with the detection of the foreign matter on the sample surface by irradiating the inspection light. A scanning means for scanning an electron beam; and a scanning electron microscope having an electron detector for detecting electrons emitted from a sample scanned with the electron beam, and obtaining a scanning electron image based on a detection result from the electron detector; ,
An interferometer that irradiates the sample surface with measurement light and detects the height position of the sample using interference of reflected light from the sample surface;
The electron detector includes a phosphor layer for electron / light conversion, a wavelength filter restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and the fluorescence transmitted through the wavelength filter. A wavelength detecting element that receives light and converts light / electricity,
The measurement light is set so as to have a wavelength outside the transmission wavelength band of the wavelength filter received by the wavelength detection element in order to acquire the scanning electron image,
An electron microscope apparatus configured to be capable of detecting the height position of the sample by irradiating the measurement light simultaneously with observation by the scanning electron image. A scanning means for scanning an electron beam; and a scanning electron microscope having an electron detector for detecting electrons emitted from a sample scanned with the electron beam, and obtaining a scanning electron image based on a detection result from the electron detector; Irradiating the sample with illumination light and receiving reflected light from the sample to obtain an optical image; and irradiating the sample surface with inspection light and detecting scattered light from the foreign matter to detect foreign matter. A foreign matter detection device to perform;
An interferometer that irradiates the sample surface with measurement light and detects the height position of the sample using interference of reflected light from the sample surface;
The electron detector includes a phosphor layer for electron / light conversion, a wavelength filter restricted so that all or substantially all of the wavelength band of fluorescence from the phosphor layer is transmitted, and the fluorescence transmitted through the wavelength filter. A wavelength detecting element that receives light and converts light / electricity,
The illumination light, the inspection light, and the measurement light have a wavelength outside the transmission wavelength band of the wavelength filter that is received by the wavelength detection element to acquire the scanning electron image, and the illumination light, The inspection light and the measurement light are set to have different wavelength bands,
Optical image observation by irradiating the illumination light, detection of foreign matter on the sample surface by irradiating the inspection light, scanning electron image observation by the electron beam, and height of the sample by irradiating the measurement light An electron microscope apparatus configured so that position detection is possible at the same time. The illumination light is white light, and a wavelength filter that transmits a wavelength band that is out of the transmission wavelength band of the wavelength filter is detachably provided on the optical path of the illumination light, and a scanning electron image by the scanning electron microscope At the time of observation, the wavelength filter is inserted to enable simultaneous observation with an optical image. When the scanning electronic image observation is not performed, the wavelength filter is removed and separated from the scanning electronic image observation to separate the optical image. The electron microscope apparatus as described in any one of Claims 1-3 which enabled observation. Any one of claims 1 to 3, characterized in that the removably said wavelength filter all or substantially all of the wavelength bands of fluorescence was limited during the transmission from the phosphor layer The electron microscope apparatus described in 1.

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