JPS60189148A - Scanning electron ray device - Google Patents

Abstract

PURPOSE:To enable adjustments such as focusing and astigmatism correction to be easily performed by equipping an image display device with a circuit for displaying an image pickup position for an image pickup device. CONSTITUTION:An image-pickup-position-displaying circuit 4 is constituted of a comparator 16 which compares an image pickup position signal produced by a scanning-coil-driving circuit 8 with an image dislay position signal produced by a CRT deflecting-coil-driving circuit 13 and produces a signal when an image pickup position and an image display position corresponding to the above signals coincide with each other, a cursor circuit 17 which produces a cursor image signal according to the signal of the comparator 16 and the image display position and an adder 14 which adds up the cursor image signal and image information read out from the memory device. As a result, an area of the sample surface actually scanned at that point is displayed on a CRT display as a cursor, thereby enabling focusing and astigmatism correction of the electroptical system to be performed while observing the whole image of the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a scanning electron beam apparatus such as a scanning electron microscope.

(Prior art) In general, in scanning electron beam devices such as scanning electron microscopes, when the scanning speed of the electron beam irradiated onto a sample is increased, the amount of information in the signal decreases, and the image quality becomes more susceptible to noise. Because of this, the scanning speed of the electron beam is reduced, and the image signal is changed to a carbon fiber with high afterglow property in response to this scanning speed.
I was trying to display it on the RT display so that I could get a sense of it.

However, in order to observe a sample with such an apparatus, the observer must follow the bright lines on the CRT display with his/her eyes, and therefore, in order to observe the entire image, this screen must be photographed. For this reason, a so-called scan converter is sometimes used to observe the entire image on a CRT display.

This scan converter A/D converts an image signal obtained by scanning an electron beam over a sample at low speed and writes it into an address corresponding to the scanning position on the sample in a storage device, while also visually checking the image signal. The information at the address corresponding to the scanning position of the CRT display, which scans at a higher speed than can be captured as an image, is read out and D/A converted to the CRT display.
It modulates the brightness of the display.

However, when such a scan converter as described above is employed, problems occur when performing focusing, astigmatism correction, etc. in the electron optical system. This is because such adjustments must be made while visually following and observing the image of the area on the sample where the electron beam is actually irradiated, but the screen obtained through the scan converter does not show the actual sample surface. This occurs because the location being scanned is not clearly visible, making it difficult to follow the actual scanning position with the naked eye. This problem is particularly noticeable when obtaining an image of a sample with little change over time, such as during examination using a scanning electron microscope.

(Object of the invention) This invention was made in view of the above-mentioned problems, and
Even if a scan converter is used in a scanning electron beam device,
It is an object of the present invention to provide a scanning electron beam device that clearly displays the point where a sample is actually irradiated with an electron beam and allows easy adjustments such as focusing of an electron optical system and correction of astigmatism. purpose.

(Structure of the Invention) This object is a scanning electron beam device that writes image signals from an imaging device that scans at a low speed into a storage device, and reads image signals from this storage device as appropriate and displays them on an image display device that scans at a high speed. The present invention is achieved by a scanning electron beam apparatus, characterized in that the image display device is provided with an image pickup display circuit that displays the image pickup position of the image pickup device.

(Example of the invention) Next, an embodiment of the present invention will be described based on seven drawings.

FIG. 1 is a block diagram showing a scanning electron microscope according to a first embodiment of the present invention. The scanning electron microscope of this embodiment includes an imaging device 1 and a storage device connected to this imaging device 1. 2, an image display device 3 connected to this storage device 2, the above-mentioned imaging device 1, and the above-mentioned storage device 2. and an imaging position display circuit 4 connected to the image display device 3.

The imaging device 1 includes an electron beam source 5 that generates an electron beam E, a scanning coil 8 that scans a predetermined range 7 on a sample 7 with the electron beam E, and a sample 7 that is irradiated with the electron beam E. Detectors 9 and 1 that detect the secondary electron beam e, electron beam s5 and sample 7
A focusing lens (not shown) provided between
It has an electron optical system consisting of. The scanning coil 6 includes a scanning coil that drives the electron beam E to scan and irradiate a predetermined location on the sample 7 at low speed, and generates an imaging position signal that indicates the position where the electron beam E is scanned. A drive circuit 8 is connected. ''-The signal detected by the detector 8 is amplified by the amplifier IO and outputs a captured image signal.

The storage device is connected to the scanning coil drive circuit 8, the amplifier 10, the CRT deflection coil drive coil 13, and the adder 14, and stores the data from the amplifier 10 at an address corresponding to the imaging position signal generated by the scanning coil drive circuit 8. While the image information corresponding to the captured image signal is rewritten one after another, the image information at the address corresponding to the image display position signal generated by the CRT deflection coil drive circuit 13 is read out one after another.

The image display device 3 includes a CRT (cathode ray Φ tube) 11 and a deflection coil 12 of the CRT 11.
A CRT deflection coil drive circuit 13 that causes the RT 11 to scan at such a high speed that scanning cannot be visually confirmed, and generates an image display position signal indicating the scanning position.
and an amplifier 15 for displaying image information from the adder 14 on the 0RT11.

The imaging position display circuit 4 then compares the imaging position signal generated by the scanning coil drive circuit 8 with the image display position signal generated by the CRT deflection coil drive circuit I3, and displays the imaging position and image corresponding to both signals. A comparator 1θ generates a signal when the positions match, and this comparator 16 is connected to the CRT deflection coil drive circuit described in 1. Based on the signal of the comparator 16 and the image display position, an arbitrary shape and arbitrary brightness can be obtained. A cursor circuit 17 that generates a cursor image signal adds the cursor image signal and the image information read from the storage device, and generates the cursor image signal (
and (d) an adder 14 that generates an image signal for simultaneously displaying a cursor image at an image display position corresponding to the image capturing position.

Therefore, according to the scanning electron microscope according to this embodiment, in the imaging device 1, the scanning of the electron beam E for imaging is performed at a low speed, and while a high-quality image signal is written in the storage device 2, the table 71 <In the device 3, the image signal stored in the storage device 2 is read out at high speed and scanned at high speed to display the image on the CRT display. You can view the entire image by displaying it above. In addition, since the point where the sample surface is actually being scanned is displayed as a cursor on the CRT display (1-), it is possible to focus the electron optical system and correct astigmatism while observing the entire image of the sample, just as before. can be done.

FIG. 2 is a block diagram showing an electron microscope according to another embodiment of the present invention, and the same parts as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted. In this embodiment, in addition to the circuit of the first embodiment, the display device includes a switch S, a CRT with a scanning line number of +8 for photographing plate speed scanning, and this CRT.
A CRT deflection coil drive circuit 20 for driving the deflection coil 18 of the RT 18 is provided. And this CR
At T18, the cursor circuit 17 is not connected, and no cursor is displayed on this CRT 1'8.

Therefore, in the scanning electron microscope according to this embodiment, in addition to the effects provided by the scanning electron microscope according to the first embodiment described above, there is an effect that photography can be easily performed. .

In addition, in the embodiments mentioned above, CRT display
- The electron beam irradiation position was displayed using a cursor image of an arbitrary shape and arbitrary C brightness, but the invention is not limited to this. It may be displayed as a dot that emits light, or it may be displayed only on a part of one side of the CRT. Further, in the above embodiment, a scanning electron microscope was used as an example, but it goes without saying that the present invention can be applied to other scanning electron beams and devices.

(Effects of the Invention) As explained above, in the present invention, the scanning position of the imaging device that scans at low speed can be displayed on the display device that scans at high speed, so while observing the entire image on the high speed scanning display device, When performing focusing and astigmatism adjustments, the location where the electron beam is currently scanning on the sample is clearly displayed on the display, making it easy to perform the focusing and other adjustments described in -1- It has the effect of being able to

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a scanning electron microscope according to a first embodiment of the invention, and FIG. 2 is a block diagram showing a scanning electron microscope according to another embodiment of the invention. l... Imaging device 2... Storage device '3... Image display device 4... Imaging position display circuit patent applicant Akashi Seisakusho Co., Ltd.

Claims (3)

[Claims] (1) In a scanning electron beam device that writes image signals from an imaging device that scans at low speed into a storage device, and reads image signals from this storage device as appropriate and displays them on an image display/device that scans at high speed, A scanning electron beam device, characterized in that the device is provided with an imaging position display circuit for displaying an imaging position of the imaging device. (2) The imaging position display circuit includes a comparator that compares the imaging position signal of the imaging device and the image display position signal of the image display device and generates a signal when both signals match, and a signal from this comparator. A scanning electron beam apparatus according to claim 1, further comprising a brightness modulator that generates a brightness modulation signal to an image signal input to a display device based on the following. (3) The imaging position display circuit includes a comparator that compares the imaging position signal of the imaging device and the image/display position signal of the image display device and generates a signal when both signals match; 2. The scanning electron beam apparatus according to claim 1, further comprising a cursor signal generator that displays a cursor at a position corresponding to the imaging position of the image display device based on the signal.