JP4613554B2 - electronic microscope - Google Patents

Description

  The present invention relates to an electron microscope, and more particularly to an electron microscope capable of observing a three-dimensional image of unevenness on a sample surface based on secondary electrons emitted from the sample surface.

  In a conventional electron microscope, an electron beam emitted from an electron gun is thinly focused by a focusing lens and an objective lens, and this electron beam is irradiated onto a small spot area on the sample surface. Secondary electrons emitted from the sensor are detected by a secondary electron detector, and the sample stage on which the sample is placed is moved minutely in a three-dimensional manner by a minute moving means, thereby enabling precise three-dimensional scanning. Based on the secondary electron detection signal from the secondary electron detector and the three-dimensional scanning data, the calculation unit calculates the three-dimensional image data of the sample surface unevenness, and the sample surface unevenness according to the three-dimensional image data based on the calculation result Are displayed on a monitor television (for example, see Patent Document 1).

JP-A-8-212959

  By the way, the conventional electron microscope requires a focusing lens and an objective lens for irradiating a pointed minute region on the sample surface as an electron beam narrowed down from an electron gun. Is required to include a relatively expensive piezo element for precisely moving the sample three-dimensionally, and a sample based on the secondary electron detection signal and the three-dimensional scanning data from the secondary electron detector. There is a need for a relatively expensive calculation unit for calculating the three-dimensional image data of the uneven surface, and there is a problem that the configuration as a whole is complicated and expensive.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electron microscope that has a simple configuration and can reduce costs.

In order to achieve the above object, this invention emits an electron beam in a predetermined direction and emits secondary electrons from the sample surface, and takes in the secondary electrons from the sample surface. A two-dimensional type secondary electron detection means for outputting a left eye electron detection signal and a right eye secondary electron detection signal, a moving means for moving the electron beam generation means and the secondary electron detection means, and the left eye 3D display means for displaying a left-eye image based on the secondary electron detection signal for the right eye and displaying a right-eye image based on the secondary electron detection signal for the right eye, and the secondary electron detection means comprises: It has a pair of secondary electron intake ports arranged at a predetermined interval, outputs a left-eye electron detection signal based on the secondary electrons taken from one secondary electron intake port, and outputs the other 2 Imported from the next electronic port On the basis of the following electronic outputs electronic detection signal for the right eye, the electron beam generating means, wherein disposed secondary electrons detector integrally with said moving means, said pair of secondary electrons capture by moving back and forth The electron beam generating means and the secondary electron detecting means are moved so that the positional relationship between the mouth and the electron beam emission direction by the electron beam generating means becomes equal.

According to the present invention, it is possible to easily observe a stereoscopic image while simplifying the configuration and reducing the cost.

(First embodiment)
FIG. 1 shows a schematic configuration diagram of an electron microscope as a first embodiment of the present invention. The electron microscope includes a control unit 1 for controlling the entire apparatus, a vacuum vessel 2, a joystick 3, an observation glasses 4 and the like. As will be described in detail later, the joystick 3 is operated while observing with the observation glasses 4. Then, a three-dimensional image of the unevenness of the region to be observed on the surface of the sample 6 placed on the sample stage 5 provided in the lower part of the vacuum vessel 2 maintained in an appropriate vacuum state by an evacuation means (not shown) can be simplified. Can be observed.

  An electron gun 7 is provided above the sample stage 5 in the vacuum vessel 2. The electron gun 7 accelerates the electrons emitted from the cathode at the anode, and emits the accelerated electrons downward in a shower shape. The electron beam 8 emitted in a shower shape downward from the electron gun 7 is applied to the entire surface of the sample 6 placed on the sample table 5.

  In the vacuum vessel 2, a secondary electron detection unit 9 and a moving mechanism 10 for moving the secondary electron detection unit 9 are provided. In this case, the moving mechanism 10 does not need to precisely move the secondary electron detector 9 and is not shown in detail. For example, the secondary mechanism is driven by a motor through a wire, an arm, etc. The structure is such that the electron detector 9 is simply moved at a relatively low speed in the front-rear, up-down, left-right directions.

  That is, when one operating rod 11 is operated from the joystick 3, a movement signal for simply moving the secondary electron detector 9 in the front-rear, up-down, left-right directions at a relatively low speed is given to the control unit 1. , The control unit 1 drives the scanning unit 12, thereby driving the moving mechanism 10 so that the secondary electron detection unit 9 is simply moved at a relatively low speed in the front-rear, up-down, left-right directions. It has become.

  The secondary electron detector 9 includes a left-eye secondary electron detector 13 and a right-eye secondary electron detector 14. These two secondary electron detectors 13 and 14 produce a constant parallax in the left and right directions of the secondary electrons 15 emitted from the small region 6a having a certain area on the surface of the sample 6 placed on the sample stage 5. It is arranged to be taken in. The schematic configuration of the secondary electron detectors 13 and 14 is as shown in FIG.

  That is, the secondary electron detectors 13 and 14 take in the secondary electrons 15, and give the energy necessary for causing the taken-in secondary electrons 15 to illuminate a fluorescent panel 17 described later, and the high-pressure grid 16. The electromagnetic lens 16 for enlarging / reducing the secondary electrons 15 after passing through, and the fluorescence corresponding to the intensity by irradiation of the secondary electrons 15 such as a scintillator having a fluorescent substance, disposed behind the electromagnetic lens 17. And a sensor panel 19 having a photoelectric conversion element formed of amorphous silicon or a single crystal semiconductor, which is disposed in close contact with the rear side of the fluorescent panel 18.

  The left-eye secondary electron detector 13 and the secondary-electron right-eye secondary electron detector 14 respectively detect the left-eye secondary electron detection signal and the right-eye secondary electron detection according to the intensity of the captured secondary electrons 15. A signal is supplied to the control unit 1. In this case, the fluorescent panel 18 and the sensor panel 19 are of a two-dimensional (plane) type, and are two-dimensional (X coordinate, Y-direction) from the secondary electron detector 13 for the left eye and the secondary electron detector 14 for the secondary electron right eye. The secondary electron detection signal for the left eye and the secondary electron detection signal for the right eye are output. The control unit 1 converts the left-eye image data and the right-eye image data corresponding to the supplied left-eye secondary electron detection signal and right-eye secondary electron detection signal, respectively, into the left-eye display drive unit 20 and the right-eye display drive unit 21. To supply.

  Although not shown in detail, the observation glasses 4 have a left-eye observation window 22 and a right-eye observation window 23 at portions corresponding to the left and right eyes of the observer, and are located behind the observation windows 22 and 23. It has a structure having a left-eye display panel and a right-eye display panel composed of a liquid crystal display panel or the like. The left-eye display panel is driven by the left-eye display driving unit 20 to display a left-eye image corresponding to the left-eye image data, and the right-eye display panel is driven by the right-eye display driving unit 21 to be used for the right eye. A right eye image corresponding to the image data is displayed.

  Next, the operation of this electron microscope will be described. When the electron beam 8 emitted in a shower shape downward from the electron gun 7 is irradiated to the entire surface of the sample 6 placed on the sample table 5, secondary electrons 15 are emitted from the entire surface of the sample 6. The In this state, the two left-eye secondary electron detectors 13 and the secondary-electron right-eye secondary electron detectors 14 located at certain positions move the secondary electrons emitted from the small region 6a on the surface of the sample 6 to the left and right. Are simultaneously detected with a certain parallax.

  Then, the left-eye secondary electron detector 13 and the secondary-electron right-eye secondary electron detector 14 respectively detect the left-eye secondary electron detection signal and the right-eye secondary electron according to the intensity of the detected secondary electrons 15. The detection is supplied to the control unit 1. The control unit 1 outputs the left-eye image data and the right-eye image data corresponding to the supplied left-eye secondary electron detection signal and right-eye secondary electron detection signal, respectively, to the left-eye display drive unit 20 and the right-eye display drive unit. 21.

  Then, the left-eye display panel provided in the back of the left-eye observation window 22 of the observation glasses 4 is driven by the left-eye display drive unit 20 and displays a left-eye image corresponding to the left-eye image data. Simultaneously with the display of the left-eye image, the right-eye display panel provided in the back of the right-eye observation window 23 of the observation glasses 4 is driven by the right-eye display driving unit 21 and corresponds to the right-eye image data. Display the right eye image.

  Therefore, the observer uses the left-eye image displayed on the left-eye display panel and the right-eye display panel provided at the back of the left-eye observation window 22 and the right-eye observation window 23 of the observation glasses 4, and When the right-eye image is observed at the same time, an uneven three-dimensional image of the small region 6a on the surface of the sample 6 is observed due to a stereoscopic phenomenon due to the binocular parallax.

  Then, when the observer operates the operation bar 11 of the joystick 3 in a desired direction while observing the stereoscopic image, a movement signal corresponding to the operation is supplied from the joystick 3 to the control unit 1. Then, the control unit 1 drives the scanning unit 12 according to the supplied movement signal, and thereby the movement mechanism 10 is driven to detect the secondary electron detector 13 for the left eye and the secondary electron detection for the secondary electron right eye. The vessel 14 simply moves in the desired direction at a relatively low speed.

  Therefore, the observer observes the operation rod 11 of the joystick 3 in a desired direction (direction to be observed) while observing the three-dimensional image of the unevenness of the small area 6 a on the surface of the sample 6 through the observation glasses 4. When the operation is performed, it is possible to easily observe a three-dimensional image of unevenness in a small area that continues in a desired direction (direction to be observed) from the small area 6a on the surface of the sample 6.

  By the way, this electron microscope only emits the electron beam 8 downward from the electron gun 7 in a shower shape, and does not include a focusing lens and an objective lens. In addition, the secondary electron detector 9 is simply moved in a desired direction at a relatively low speed, and a relatively expensive piezo element for moving the sample stage minutely in a three-dimensional manner as in the prior art is used. It does not require a minute moving means.

  Further, when the operation rod 11 of the joystick 3 is operated in a desired direction while observing a three-dimensional image of the unevenness of the small area 6a on the surface of the sample 6 through the observation glasses 4, the surface of the sample 6 is affected. Since it is possible to easily observe a three-dimensional image of unevenness in a small area that continues from the small area 6a in a desired direction, a comparatively expensive arithmetic unit is not required as in the prior art. From the above, this electron microscope has a simple configuration and can reduce the cost.

  In this electron microscope, as shown in FIG. 2, the secondary electron detectors 13 and 14 include the electromagnetic lens 17 for enlarging and reducing the secondary electrons 15. , The stereoscopic image may be enlarged or reduced while observing the stereoscopic image with the observation glasses 4.

(Second Embodiment)
In the first embodiment, the electron gun 8 provided in the upper part of the vacuum vessel 2 emits the electron beam 8 downward in a shower shape to irradiate the entire surface of the sample 6. However, the present invention is not limited to this. It is not something. For example, as in the second embodiment of the present invention shown in FIG. 3, the electron gun 7 is provided on the upper surface of the secondary electron detector 9 so as to be movable together with the secondary electron detector 9. May be emitted toward a small region 6 a on the surface of the sample 6, that is, a secondary electron detection region by the secondary electron detectors 13 and 14. In this case, since the electron irradiation region by the electron gun 7 and the secondary electron detection region by the secondary electron detectors 13 and 14 are substantially the same, the amount of secondary electron detection increases and a bright image is obtained. can get.

(Third embodiment)
In the first and second embodiments, the left-eye secondary electron detector 13 and the right-eye secondary electron detector 14 are used. However, the present invention is not limited to this. For example, as in the third embodiment of the present invention shown in FIG. 4, a secondary electron detector 31 having a left-eye secondary electron intake port 32 and a right-eye secondary electron intake port 33 may be used.

  That is, the secondary electron detector 31 includes a left-eye high-voltage grid 34 and a left-eye polarizing electrode 36 provided in the left-eye secondary electron intake port 32, and a right-eye secondary electron intake port 33 provided in the right-eye secondary electron intake port 33. The high-voltage grid 35 and right-eye polarizing electrode 37, the left-eye polarizing electrode 36 and the right-eye polarizing electrode 37, the common polarizing electrode 38 disposed at the subsequent stage, and the secondary electrons 15 after passing through the common polarizing electrode 38 are enlarged or reduced. An electromagnetic lens 39, a fluorescent panel 40 arranged at the rear stage of the electromagnetic lens 39, and a sensor panel 41 arranged in close contact with the rear stage side of the fluorescent panel 40.

  In the electron microscope equipped with the secondary electron detector 31, the voltages applied to the left-eye high-voltage grid 34 and the left-eye polarizing electrode 36, the right-eye high-voltage grid 35 and the right-eye polarizing electrode 37 are alternately switched at high speed. The left-eye secondary electron detection signal and the right-eye secondary electron detection signal are alternately output at high speed from the sensor panel 41, and the left-eye image and the right-eye are displayed by the left-eye display panel and the right-eye display panel of the observation glasses. Since the work images are alternately displayed at a high speed, a stereoscopic image is observed by the observer due to the stereoscopic phenomenon due to the binocular parallax and the afterimage phenomenon.

  In each of the above embodiments, one display panel is provided behind the observation glasses, and the left-eye observation window and the right-eye observation window are used as the left-eye liquid crystal shutter and the right-eye liquid crystal shutter. Left and right eye images are displayed alternately at high speed, and the left and right eye liquid crystal shutters are opened and closed according to the timing of switching between the left eye image display and the right eye image display. You may make it switch. Further, when the right-eye image and the left-eye image are alternately displayed on one display panel, the glasses may not be used.

  Further, as an example, as schematically shown in FIG. 5, the moving mechanism 10 includes a ring-shaped rail 51 provided above the periphery of the sample stage, and a first member 52 that reciprocates by driving a motor on the rail 51. The second member 53 that moves up and down by driving the motor is attached to the first member 52, and the third member 54 that reciprocates in the radial direction of the rail 51 by driving the motor is attached to the second member 53, The secondary electron detector 9 may be attached to the tip of the third member 54.

  As another example, as schematically shown in FIG. 6, the moving mechanism 10 is provided with a ring-shaped rail 51 above the periphery of the sample stage, and a moving member 55 that reciprocates by driving a motor on the rail 51. The base end portion of the articulated arm 56 may be attached to the attaching and moving member 55, and the secondary electron detection unit 9 may be attached to the distal end portion of the articulated arm 56.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the electron microscope as 1st Embodiment of this invention. The schematic block diagram of the secondary electron detector shown in FIG. The schematic block diagram of a part of electron microscope as 2nd Embodiment of this invention. The schematic block diagram of the secondary electron detector of the electron microscope as 3rd Embodiment of this invention. The schematic block diagram of an example of a moving mechanism. The schematic block diagram of the other example of a moving mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control part 2 Vacuum container 3 Joystick 4 Observation glasses 5 Sample stand 6 Sample 7 Electron gun 9 Secondary electron detection part 10 Movement mechanism 12 Scan part 13 Secondary electron detector for left eye 14 Secondary electron detector for right eye 20 Left eye Display Drive Unit 21 Right Eye Display Drive Unit

Claims (3)

An electron beam generating means for emitting an electron beam in a predetermined direction and emitting secondary electrons from the sample surface;
Two-dimensional type secondary electron detection means for taking in secondary electrons from the sample surface and outputting a two-dimensional type left-eye electron detection signal and a right-eye secondary electron detection signal;
Moving means for moving the electron beam generating means and the secondary electron detecting means;
Stereoscopic display means for displaying a left-eye image based on the left-eye secondary electron detection signal and displaying a right-eye image based on the right-eye secondary electron detection signal;
The secondary electron detection means has a pair of secondary electron intake ports arranged at a predetermined interval, and detects left-eye electrons based on secondary electrons taken from one of the secondary electron intake ports. Output a signal, and output a right eye electron detection signal based on the secondary electrons taken from the other secondary electron inlet,
The electron beam generating means is disposed integrally with the secondary electron detecting means,
The moving means includes the electron beam generating means and the secondary electron detecting unit so that the positional relationship between the pair of secondary electron intake ports and the electron beam emitting direction by the electron beam generating means is equal before and after the movement. An electron microscope characterized by moving the means. In the invention of claim 1,
An electron microscope characterized in that secondary electrons taken from the one secondary electron take-in port and secondary electrons taken from the other secondary electron take-in port are led to different fluorescent panels . In the invention of claim 1 ,
An electron microscope characterized in that the secondary electrons taken from the one secondary electron take-in port and the secondary electrons taken from the other secondary electron take-in port are guided to a common fluorescent panel.

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