JPH0524615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of digitally scanning a charged particle beam on a sample surface and displaying a sample image based on signals obtained in association with the scanning.

For example, in an X-ray microanalyzer, the surface of a sample is scanned two-dimensionally with an electron beam, and the X-rays obtained as a result of this scanning are detected.
A two-dimensional image of the sample is displayed based on this detection signal. At this time, if digital scanning is used to move the electron beam irradiation position intermittently, damage to the sample due to the electron beam can be reduced and analysis time can be saved. When displaying a two-dimensional image of a sample using this digital scanning, if you want to display a high-resolution image, you can reduce the interval between electron beam irradiation positions and irradiate the electron beam densely. The amount of data that must be collected increases with the square of the resolution.
It takes an extremely long time to form one screen. Therefore, it is possible to determine whether or not the area in which the image is to be displayed is an area of interest, to determine whether or not to continue collecting data, and to determine whether the display color assignment is appropriate when displaying the image in color. In order to determine whether or not this is the case, it is necessary to set a large interval between the irradiation positions of the electron beam on the sample surface, roughly scan the sample, and grasp the entire rough image in a short time. In this case, in the past, the number of display points on the display screen was reduced, making the image scattered and difficult to observe.

The present invention solves these conventional drawbacks and provides a method for displaying two-dimensional data in a charged particle beam device, etc., which can display a visually natural image even when roughly scanning a sample surface. The purpose is to

The present invention irradiates a charged particle beam to an irradiation point corresponding to each thinned out pixel out of all pixels distributed two-dimensionally, and a pixel corresponding to each irradiation point receives a detection signal obtained from each irradiation point. The sample image is displayed two-dimensionally by displaying the pixel of each non-irradiation point using an alternative signal created based on the detection signal of the irradiation point near each non-irradiation point. A method for displaying two-dimensional image data in a charged particle beam device, etc., in which the pixels displayed by the alternative signal are automatically decreased by a predetermined amount each time one screen is displayed, each time one screen is scanned. The method is characterized in that the sample is scanned by the charged particle beam and displayed on the screen while increasing the density of the irradiation or the density of the irradiation points combined with the irradiation points up to the previous scan.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 shows an apparatus for carrying out the present invention. In the figure, 1 is a housing of an X-ray microanalyzer, and within this housing 1 an electron gun 2 is arranged. The electron beam 3 from this electron gun 2 is deflected by a deflector 4.
The beam is deflected by the beam and irradiated onto the sample 5. electron beam 3
In order to control the irradiation position on the sample 5, a deflection signal generated in a deflection circuit 7 based on a signal from an electronic computer 6 is supplied to the deflector 4. 8 is a wavelength dispersive X-ray detector, and a detection signal from this detector 8 is supplied to a data storage memory 10 via an AD converter 9. A signal from this memory 10 is supplied to a cathode ray tube 11 for image display under the control of the electronic computer 6.

In such a configuration, for example, it is possible to scan and display the surface of the sample 5 by dividing it into a maximum of 100 x 100 pixels, and these pixels are associated with symbols as shown in Figure 2. shall be taken as a thing. First, as shown in the flowchart shown in FIG. 3, a number N indicating how many pixels to irradiate with an electron beam during scanning is set. However, N is a power of 2 (step 1). Next, based on this set number N, a control signal is supplied from the electronic computer 6 to the deflection circuit 7 to select every N pixels, that is, pixels i×N (i=0, 1,
2, 3, ...) is irradiated with the electron beam 3 to scan the sample 5. And this electron beam 3
The detection signal obtained with the irradiation is sent to the detector 8 and
The data is stored in the address corresponding to each pixel in the data storage memory 10 via the AD converter 9 (step 2).
Next, under the control of the electronic computer 6, the data of the nearest pixels among the pixels whose data was collected is transferred and stored at each address of the memory 10 corresponding to each pixel that was not irradiated with the electron beam. interpolation work is performed (step 3). These nearby pixels include, for example, codes i×N+1, i×N+2, ..., i×N
For the pixel corresponding to +(N-1), pixel i
Select ×N. Next, under the control of the electronic computer 6, display data for all pixels is read out from the memory 10 and supplied to the cathode ray tube 11 to display an image of the sample 5 (step 4). Next, the number of pixels irradiated with the electron beam is compared with the target value _N0 , and it is determined whether the density of the collected data is sufficient (step 5). if,
If the number of collected data is insufficient, set N to N/2.
After reducing the number of data, the process returns to step 1, and the operations after step 1 are performed to collect data more densely. In the process of collecting data more densely, the newly collected data is stored at a corresponding address in the memory 10. Therefore, when displaying an image in step 4, pixels whose data has been newly collected by irradiation with the electron beam 3 will be displayed based on the data collected instead of the interpolated data. . In this way, as the number of loop iterations increases, the number of pixels displayed based on interpolated data decreases, and the number of pixels displayed based on actually detected data increases, increasing the resolution of the image. . During this process, if it is found from observation of the image that the area in which the image is to be displayed is an area of no interest, data acquisition is stopped at that point and data acquisition is moved to, for example, another area. . If this is not the case, data collection is terminated after data has been collected for pixels of the target density. Note that in the above example, if N is reduced, a certain pixel will be irradiated with the electron beam overlappingly, but it is determined whether the irradiation point has already been irradiated with the electron beam or not. Of course, the irradiation point where the beam was irradiated is skipped and the electron beam is not irradiated.

The embodiment described above is only one embodiment of the present invention, and the present invention may be implemented in many other forms.

For example, in the above-described embodiment, the charged particle beam was first irradiated to the irradiation points every N pixels in order to form a schematic image, but as shown by diagonal lines in FIG. The electron beam may be irradiated every other time.

Also, as shown in Figure 5, for example, data is collected by irradiating 4x4 pixels one by one as indicated by diagonal lines in the figure, and the 4x4 pixels are divided into this 4x4 area. Interpolation may be performed using data collected at one point within the range.

Furthermore, although the above-mentioned embodiment describes the case where the present invention is used to display a sample image using an The present invention is similarly applicable to the case of display.

As described above, in the method based on the present invention, it is possible to observe an image in which the proportion of the portion displayed by the alternative signal automatically decreases with each screen display. Once the proportion of the area represented by the signal is acceptable for a rough understanding of the scanning area and display of the image,
Since data acquisition (scanning) in that scanning area can be stopped and the next operation can be started immediately, the efficiency of sample observation or analysis operations can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an apparatus for implementing the present invention, FIG. 2 is a diagram for explaining the pixels considered on the sample surface, and FIG. 3 is a diagram showing an example of an apparatus for implementing the present invention. FIG. 4 is a diagram for explaining the flow, FIG. 4 is a diagram for explaining another embodiment, and FIG. 5 is a diagram for explaining still another embodiment. 1: Housing, 2: Electron gun, 3: Electron beam, 4: Deflector, 5: Sample, 6: Computer, 7: Deflection circuit,
8: Wavelength dispersive X-ray detector, 9: AD converter, 1
0: memory for data storage, 11: cathode ray tube.

Claims (1)

[Claims] 1. Irradiate a charged particle beam to the irradiation point corresponding to each thinned out pixel among all the pixels distributed two-dimensionally,
The pixels corresponding to each irradiation point are displayed based on the detection signal obtained from each irradiation point, and the pixels of each non-irradiation point are displayed as alternative signals created based on the detection signal of the irradiation point close to each non-irradiation point. A method for displaying two-dimensional image data in a charged particle beam device, etc., in which a sample image is displayed two-dimensionally by displaying the sample image, wherein the pixels displayed by the alternative signal are displayed on a single screen. The sample is scanned by the charged particle beam and displayed on the screen while automatically increasing the density of the irradiation points, which is the sum of the irradiation points up to the previous scan, each time one screen is scanned so that the density decreases by a predetermined amount each time the sample is scanned. A method for displaying two-dimensional image data in a charged particle beam device, etc., characterized in that: