JP2867664B2 - Position reproduction device for electron beam micro analyzer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a position reproducing apparatus suitable for an electron probe microanalyzer.

(Prior art) An electron probe microanalyzer irradiates a focused electron beam onto a sample surface and detects secondary electrons, X-rays, and the like radiated from the sample surface, thereby changing properties near the sample surface. When the observer wants to compare and observe different positions of the same sample, the sample may be moved.

In such a case, the coordinate value of the drive mechanism from the original position is stored in the memory in order to return to the original position, and when returning to the original position, the sample stage drive mechanism is operated based on the data in the memory. I try to operate.

(Problems to be Solved by the Invention) However, since there is a backlash in a gear or the like used in the drive mechanism, an error remains in the operation amount, and there is a problem that it is extremely difficult to reproduce the position in the order of microns. .

The present invention has been made in view of such a problem, and an object thereof is to provide a position suitable for an electron beam probe microanalyzer capable of obtaining position data with high accuracy regardless of the accuracy of a driving mechanism. An object of the present invention is to provide a reproduction device.

(Means for Solving the Problem) In order to solve such a problem, in the present invention,
In an electron beam microanalyzer that irradiates an electron beam while scanning and stores the radiation from the sample in a frame memory in synchronization with the scanning, the image data at the original position, and the image data after moving the sample in the horizontal direction, A binarized image conversion unit for binarizing the stored image data in the frame memory and storing the binarized image data in a buffer memory; a unit for labeling a unique pattern of the image data in the buffer memory; , Pattern matching means for comparing the shapes of patterns having the same area, and means for calculating the movement amount.

(Effect of the Invention) The contrast of the original position and the image data after the movement is enhanced and binarized, and a label is attached to each pattern. When returning to the original position, the areas of the patterns of the same label are compared, coarse sieving of the same is performed, and then the patterns having the same area are determined by the pattern matching method. As a result, it is possible to prevent a comparison operation between patterns deformed due to aberrations or the like, thereby improving the calculation speed. Next, if the distance between the matching patterns is calculated, the moving amount of the sample stage can be known.

(Embodiment) Therefore, the details of the present invention will be described below based on an illustrated embodiment.

FIG. 1 shows an embodiment of the present invention. In the drawing, reference numeral 1 denotes an electron beam generator, which focuses thermoelectrons from a filament 2 by a focusing lens 3 and passes through an objective aperture lens 4. The sample is made incident on the objective lens 5 to irradiate the sample on the sample stage 6.

Reference numeral 6 denotes a sample stage, which moves the sample in a plane and in the direction of the electron beam irradiation axis by a fine movement driving mechanism 7. Numeral 8 denotes a radiation detector, which in this embodiment receives X-rays through an X-ray spectrometer 9 because X-rays are to be detected among the radiations emitted from the sample surface. This is output to the processing device 10.

Reference numeral 10 denotes a signal processing device including the above-described microcomputer, which generates an image signal based on a signal from the radiation detector 9 and stores the image signal in the memory 11, and also outputs an image signal to a display 12 such as a cathode ray tube, and further performs a focus adjustment. It is configured to output a signal to the XY axis drive circuit 13 of the fine movement drive mechanism 7.

FIG. 2 shows the functions to be performed by the microcomputer, and calculates the density of each pixel of the image data in the frame memory 21 constituted by the memory 11 and the frequency thereof to create a density histogram. A histogram calculating means 22, a density converting means 23 for creating a density conversion curve from a density histogram, and a binary value for binarizing image data in the frame memory 21 based on the data of the density conversion curve and storing the image data in the buffer memory 25. Image conversion means 24, labeling means 26 for labeling a pattern serving as a marker of the image data in the buffer memory 25, area calculating means 27 for calculating the area of the labeled figure, and image data at the original position. An area comparing means 28 for comparing the area of the labeled figure with the figure after the movement, a pattern matching means 29, and an image data at the original position. It is programmed to include a distance calculation unit 30 for calculating the distance between the image data after movement and data.

Next, the operation of the apparatus configured as described above will be described based on the flowchart shown in FIG.

When the apparatus is operated with a sample placed on the sample stage 6, the electron beam from the electron beam generator 1 is focused on the focusing lens system 3,
The sample surface is irradiated while being guided to 4 and 5 two-dimensionally, and X-rays are emitted from each irradiation point. This X-ray is detected by the detector 8 and stored in the frame memory 21 in synchronization with the scanning of the electron beam.

On the other hand, the histogram calculating means 22 detects the density of each pixel of the image data stored in the frame memory 21 and calculates a histogram of the pixel density (FIG. 4).
The density conversion means 23 calculates a density conversion curve (FIG. 5) integrated in order from the lowest density frequency based on the histogram to create image data with enhanced contrast.
This data is output to the buffer memory 24.

At this stage, labeling is performed by a labeling means 26 on a unique figure, in this embodiment, a pattern a, b, c such as a circle or a rectangle (FIG. 6A).

Next, the sample stage 6 is driven to move the target observation point into the field of view. The coordinate values obtained by this moving operation are stored in the memory as in the conventional device.

In the same manner as described above, the moving image data is subjected to the binarization processing on the image data in the frame memory 21, and then the same label a, b, c as the marker pattern which was previously labeled. The data is stored in the buffer memory 25 (FIG. 6B).

When the observation after moving is completed and it returns to the original position,
Return to the original position based on the coordinate values after the movement as in the conventional case. Of course, in the return operation at this stage,
A positioning error has occurred due to backlash or the like of the fine movement drive mechanism 7.

In this state, the areas of the original image data and the figure of the same label are compared, and if the areas match, the pattern matching method is applied to the two patterns to determine their identity. If the areas of the figures of the same label do not match, the areas of the patterns of different labels are compared, and if they match, the pattern matching method is applied to this new pattern. As a result, patterns deformed due to aberrations and the like are excluded from comparison targets,
Useless application of the time-consuming pattern matching method can be prevented.

In this way, the X coordinate, Y
The movement of the sample stage is calculated by calculating the coordinates.

In this embodiment, the movement between two points, the original position and the second position, has been described. However, if there is enough room in the frame memory, the same effect can be obtained for three or more movements. It is clear.

Further, in this embodiment, the movement amount is calculated from the pattern at the original position and the pattern after the movement. However, the image data at the time of restoration is binarized and moved until it matches the pattern at the original position. Obviously, the same effect is obtained even if the control is performed.

Further, in this embodiment, the case where X-rays from the sample are detected and converted into image data has been described. However, the present invention is also applicable to a case where other radiations such as reflected electrons and secondary electrons are detected and converted into image data. Obviously, it has a similar effect.

Further, in this embodiment, the label is attached at the time of moving to the target position. However, it is obvious that the same effect can be obtained even if the label is attached at the stage of returning to the approximate position by the coordinate value of the memory. It is.

Further, in this embodiment, the image data in which the contrast is enhanced by the histogram method is obtained, but other contrast enhancement methods can be applied.

(Effects of the Invention) As described above, according to the present invention, in an electron beam microanalyzer that irradiates an electron beam while scanning and stores radiation from a sample in a frame memory in synchronization with the scanning, Binarized image conversion means for binarizing image data in a frame memory storing image data and image data after the sample has been moved in the horizontal direction and storing the binarized image data in a buffer memory; A means for attaching a label to a pattern, a means for comparing the area of a pattern with the same label, a pattern matching means for comparing the shape of a pattern having the same area, and a means for calculating a movement amount are provided. The distance between the image at the point and the moved image can be calculated based on the figure data, and the back of the mechanism that drives the sample stage The distance between two points can be known with high accuracy without being affected by rush or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention, FIG. 2 is a block diagram showing functions performed by the microcomputer in FIG. 1, FIG. 4 and 5 show examples of a histogram and an image conversion curve, respectively, and FIG. 6 (a).
(B) is a schematic diagram showing the original position and the image data after the movement, respectively. 1 ... Electron beam generator, 6 ... Sample stand 7 ... Fine movement drive mechanism, 8 ... Radiation detector

Claims (1)

(57) [Claims] 1. An electron beam microanalyzer which irradiates an electron beam while scanning and stores radiation from a sample in a frame memory in synchronization with the scanning, wherein image data at an original position and movement of the sample in a horizontal direction are provided. Binary image conversion means for binarizing image data in the frame memory storing the subsequent image data and storing the image data in the buffer memory, and means for labeling a unique pattern of the image data in the buffer memory are the same. A position reproducing apparatus for an electron beam microanalyzer, comprising: means for comparing the area of a label pattern; pattern matching means for comparing the shapes of patterns having the same area; and means for calculating the amount of movement.