JPS60122332A - Cathode luminescence device - Google Patents

Abstract

PURPOSE:To observe cathode luminescence with invariably high resolution regardless of a scanning range by displacing a slit or reflecting mirror synchronously with the scanning of an electron beam, and guiding light from a sample into the slit. CONSTITUTION:The sample 4 is scanned in two dimensions with the electron beam through a scanning control part 8 and a deflecting coil 6. The fluorescent light from the sample 4 is converged on a spectroscope 24 through condenser lenses 21-23. A control signal from a control part 8 is supplied to the servomotor 28a of a slit driving part 28 to displace slits 30 and 32 through an actuator 28b synchronously with the scanning of the electron beam. Therefore, the converged light with specific width is incident from the entrance slit 30 and diffracted spectrally by a diffraction grating 36 to enter a detector 26 through the exit slit 32. Therefore, cathode luminescence is measured with high resolution regardless of the scanning range.

Description

[Detailed description of the invention] (a) Industrial application field The present invention is directed to an X-ray microanalyzer (KPMA).
The present invention relates to a cathodoluminescence device used as an accessory device to obtain a cathodoluminescence image with a scanning electron microscope (SFiM) or the like.

(b) Prior Art Generally, in order to obtain a cathodoluminescence image using a cathodoluminescence device, a sample is irradiated with an electron beam while scanning in two dimensions, and the light excited and emitted from the sample is guided to an optical spectrometer. A detector detects the light of a specific wavelength separated by this optical spectrometer. In this way, since the electron beam is two-dimensionally scanned to obtain a cathodoluminescence image of the sample, the position of the light focused on the optical spectrometer changes accordingly. Therefore, if the slit of the optical spectrometer remains fixed regardless, the slit itself will interfere with the light and will not be able to guide the light to the optical spectrometer. For this reason, in conventional devices, the slit width of the optical spectrometer is widened in accordance with the size of the scanning area of the electron beam so that light can be guided into the optical spectrometer without any problem. However, when the slit width is widened in this manner, the resolution of the optical spectrometer decreases, making it impossible to obtain a clear cathodoluminescence image.

(C) Purpose The present invention has been made in view of the above-mentioned problems, and
It is an object of the present invention to enable cathodoluminescence images to be always observed with high resolution regardless of the magnification, that is, the scanning range.

In order to achieve the above object, the present invention displaces a slit or a reflecting mirror in synchronization with electron beam scanning, and guides the light from the sample through the slit into the optical spectrometer without any hindrance. That's what I do.

(E) Example Hereinafter, the present invention will be explained in detail based on an example shown in the drawings. In this example, a case will be described in which a cathode luminescence device is attached to mPMA.

The figure is a configuration diagram of an EPMA and a cathode luminescence device attached to it. In the same figure, 1 is EPMA,
2 is a cathode luminescence device, and 4 is a sample. 6
8 is a deflection coil that deflects an electron beam emitted from an electron gun (not shown), and 8 is a scan control section that outputs an electron beam control signal to the deflection coil 8 to control scanning of the electron beam. 10.12 is a reflective objective lens, 14 is a reflective mirror, 16 is an objective lens for electron beam convergence, 18
is a secondary electron detector, which is installed in a normal EPMA. On the other hand, the cathodoluminescence device 2
A half mirror 20 for re-reflecting the light from the MAl reflecting mirror 16, a plurality of focusing lenses 21, 22, 23 for focusing the light reflected by this half mirror 20, and separating the focused light into spectra. It is mainly composed of an optical spectrometer 24, a detector 26 for detecting the light separated by the optical spectrometer 24, and a slit driving section 2B. The detector 24 includes a plurality of reflection mirrors 34, 34, . . . and a diffraction grating 36 arranged between the entrance and exit slots 30, 32.

Both slits 30 and 32 are arranged perpendicularly to the direction of incidence of light and parallel to each other, and in the rask scanning direction of the electron beam (perpendicular to the plane of the paper in the figure).
The longitudinal direction of the slit holes should match. In addition, the diffraction grating 36 also has slits 30.3 in the direction perpendicular to the grooves.
It is arranged to match the longitudinal direction of the two holes.

The slit drive unit 2B drives the slit drive unit 30, 32 in a direction perpendicular to the rask scan direction of the electron beam (in the left-right direction indicated by the arrow X in the figure). A motor 28a is commonly connected to the scanning control section 8, and an actuator 28b is commonly connected to both slits 30 and 32. Note that 34 is an eyepiece lens.

In the above configuration, when obtaining a cathodoluminescence image, the scan controller 8 outputs an electron beam control signal to the deflection coil 6, and by changing the magnetic field of the deflection coil 6, the electron beam irradiated onto the sample 4 is scanned by a rask. while sequentially moving in a direction perpendicular to this (X direction).

The light emitted from the sample 4 by two-dimensionally scanning the electron beam on the sample 4 is transmitted through the reflective objective lens 10.
12, the light is focused into a light spectrometer 24 by focusing lenses 21, 22, and 23 via a reflecting mirror 14 and a half mirror 20. This focal position is displaced in synchronization with the two-dimensional scanning of the electron beam. The electron beam control signal output from the scan control section 8 is also given to the servo motor 28a of the slit drive section 28 at the same time. In response to this electron beam control signal, the servo motor 28a drives the slit 30.32 via the actuator 28b only while the electron beam is moving in the X direction. Therefore, the slits 30, 32 are sequentially displaced to the left (or right) in synchronization with the electron beam as it moves from one rask scan to the next. As a result, the focused light is introduced into the optical spectrometer 24 through the entrance slit 3o while the slits 30 and 32 maintain a constant width necessary for resolution, and
Light having a characteristic wavelength separated by the diffraction grating 36 passes through the exit slit 32 and is detected by the detector 26 .

In the above embodiment, the slit is displaced in synchronization with the scanning of the electron beam, but the slit of the optical spectrometer is fixed, and instead, it is placed in the optical path from the sample 4 to the optical spectrometer 24. A mirror drive unit 36 that drives the half mirror 20 in a direction perpendicular to the rask scan direction of the electron beam (X direction in the figure) is connected to the mirror (for example, the half mirror 20 in this example), and the mirror drive unit 36 The same effect can be obtained by connecting the half mirror 20 to the scanning control unit 8, thereby slightly moving the half mirror 20 in synchronization with the electron beam scanning, and always focusing the light on the slit position.

(f) Effect As described above, according to the present invention, the slit or mirror is displaced in synchronization with electron beam scanning, so light is always guided into the optical spectrometer through the slit, so the slit width can be reduced. No need to expand. Therefore, an excellent effect can be obtained in that the cathodoluminescence image can always be observed with high resolution without being affected by the scanning range.

[Brief explanation of drawings]

The drawing is a configuration diagram of a cathode luminescence device attached to an EPMA according to an embodiment of the present invention. 1... KPMA12... cathodoluminescence device,
4. Sample, 8. Scanning control unit, 24. Optical spectrometer, 26
...Detector, 2B...Slit drive section, 30, 32...
Slit, 36...diffraction grating.

Claims (2)

[Claims] (1) Equipped with an optical spectrometer that separates light emitted from a sample by being excited by an electron beam, and a detector that detects the light separated by the optical spectrometer, and the optical spectrometer includes a slit and a diffraction grating. In the cathode luminescence device, the slit is provided with a slit drive unit that drives the slit in a direction perpendicular to the rask scan direction of the electron beam in a plane perpendicular to the direction of incidence of the light. and the slit driving section is connected to the scanning control section of the electron beam, so that the slit is displaced in synchronization with scanning of the electron beam. (2) It is equipped with an optical spectrometer that separates light emitted from a sample by being excited by an electron beam, and a detector that detects the light separated by the optical spectrometer, and the optical spectrometer includes a slit and a diffraction grating. In the cathode luminescence device, a mirror that reflects light toward the slit of the optical spectrometer is placed in the optical path from the sample to the optical spectrometer, and a mirror is attached to the mirror to reflect the light toward the slit of the optical spectrometer. A mirror driving section for driving in a direction perpendicular to the scanning direction is connected, and this mirror driving section is connected to the scanning control section of the electron beam, so that the mirror is displaced in synchronization with the scanning of the electron beam. Characteristic cathodoluminescence device.