JPS58169763A - Fixed moving zoom unit - Google Patents

Abstract

PURPOSE:To improve controllability by automatically moving the center of a scanning area in the X-Y direction using a stepping motor and moving and enlarging a desired visual field up to the center of a screen using a control switch depending upon the number of screen divisions of a CRT. CONSTITUTION:When a sample is located in position (A) on a screen, button (A) of a control switch is pressed. Thus, a signal that specifies the moving direction of a sample stand 3a is output from the control switch 11 to a control section 10. A signal that specifies the number of pulses corresponding to the present magnifying power is issued from the control section 10 and pulse generators 8 and 9 receive both signals and issue the corresponding number of pulses. Stepping motors 6 and 7 receive these ourput pulses and move the sample stand 3a in arrow direction (A). The moving distances are Sx and Sy that move a picture in the X direction by 2/8 and in the Y direction by 2/8, respectively. After the sample stand is moved, the control section 10 issues a control signal to a scanning width variable unit 4 and doubles the display picture. As a result, the moved sample picture is doubled and is displayed on the screen of the CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant movement zoom device used in a scanning electron microscope or the like.

In devices such as scanning electron microscopes and ion microanalyzers, the surface of a sample is irradiated with a finely focused charged particle beam, and at the same time, a certain area is scanned to detect various signals obtained from the sample. The detection signal is used as a brightness modulation signal for an image display device such as a CRT that is synchronized with the scanning, and a brightness modulated scanned image is displayed on the image display device. The magnification of the scanned image is determined by the ratio of the scanning width of the electron beam that irradiates the sample to the corresponding length of the display screen.

In normal sample observation, a low magnification image is first observed, and the sample moving device is manually operated so that the desired field of view is approximately in the center of the screen.

In this state, if you increase the magnification, the desired field of view will be enlarged and displayed, but if you want to observe a specific part of this expanded field of view in more detail, you can repeat the same operation using the sample moving device. is repeated. Therefore, in normal sample observation, it is necessary to perform the above-mentioned operation several times before finding the desired field of view. Moreover, the sample moving device is located at two points perpendicular to the electron beam.
The sample cannot be moved in any direction without operating the two independent heirs that move it in the X direction and Y direction, and the sample movement speed may be too fast or slow compared to the magnification. I was unable to move it in the desired direction or stop it at the desired position. Therefore,
The operator requires a great deal of time and effort to bring the desired field of view to the center of the screen.

The present invention has been made in view of these points, and is capable of automatically moving the center of an electron beam scanning area on a sample surface in two directions, X and Y, using a step motor or electromagnetic deflection means. At the same time, the CRT screen is divided by drawing lines or the like, and a control switch having push buttons corresponding to the number of divisions of the divided screen is provided, and the desired field of view of the sample is moved to the center of the screen by the control switch, and then, A constant-movement zoom device for a scanning electron microscope has been realized in which the specimen is enlarged to a predetermined magnification, and the movement of the sample and magnification zoom are integrated, and the operability is greatly improved.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an electrical configuration diagram showing an embodiment of the present invention. In the figure, 1 is a lens barrel, 2 is a scanning coil that scans a sample two-dimensionally with a beam, and 3 is a drive unit having a sample stage 3a on which a sample (not shown) is placed. 4 is a scanning width variable device that drives the scanning coil 2, and the magnification of the displayed image is as follows:
The scanning width can be changed using the scanning width variable device 4. For example, if the scanning width is reduced to 1/2, the magnification will be doubled.

5 is a scanning power supply that supplies scanning voltage to the scanning coil 2;
Reference numeral 6.7 is a step motor that is attached to the drive section 3 and moves the sample stage 3a in the X and Y directions, respectively. Reference numeral 8.9 is a pulse generator that sends drive pulses to these step motors 6.7.

Reference numeral 10 denotes a control section for controlling the scanning width variable device 4 and the pulse generator 8.9. As the control unit 10, for example, a microcomputer is used. Reference numeral 11 denotes a control switch having push buttons corresponding to the number of divisions of the CRT screen divided by lines as shown in FIG. The CRT screen of this embodiment is as shown in FIG.
The screen is divided into nine sections, and the ratio of the length occupied by each section (the same in both directions) is shown in the figure, assuming that the length of the entire screen is 1 in both directions. The divisions 8 to 1 of this CRT screen correspond to the push buttons A to 1 of the control switch 11, respectively. In order to divide the CRT screen, a transparent plate with drawn lines may be attached to the CRT, or bright lines or lines may be drawn in the CRT screen.

The operation of the apparatus of the present invention configured as described above will be explained next.

Assume that the target sample is now located at the position shown in Screen-1-Figure 2. For the operation axis, press button A on the control switch. As a result, a signal specifying the moving direction of the sample stage 3a is output from the control switch 11 to the control section 10. A signal specifying the number of pulses corresponding to the magnification is given from the control section 10, and the pulse generator 8.9 receives these two signals and outputs the corresponding number of pulses.

Stepping motor 6.7 receives output pulses from pulse generator 8.9 and moves sample stage 3a in the direction shown by arrow A in FIG. The moving distance is 2/8 of the image in the Y direction on the screen.
, 2 in the Y direction. /8 Distance to move ISx (2/8)
, Sy (2/8). After the movement is completed, the control section 10 sends a control signal to the variable scanning width device 4 to enlarge the display image on the CRT screen to 2 m. As a result, the sample image moved in the six directions of the arrows is magnified twice at that position and C
Displayed on the RT screen.

In the above-mentioned operation, the moving operation when the sample is located in the section shown in FIG. 2 has been described, but the operation is exactly the same when the sample is located in any of the sections B to (2). For example, when in the position of section G, push button G of control switch 11 may be pressed. As a result, the sample moves in the direction of arrow G in FIG. 3 and is then enlarged twice. The same goes for the case where the sample is in the position marked by A, and the sample is moved and covered in each direction as shown in Fig. 3.

However, it does not move when button E is pressed. If it is not possible to obtain a scanned image with a predetermined magnification at a predetermined position even with this first movement and enlargement operation, repeat the same operation again to finally obtain the desired image in the center of the screen. The magnification of the scanned image can be increased. Note that the scanned image displayed on the CRT screen by the first moving enlargement scan has been enlarged to twice the magnification, so when performing the second moving enlargement operation, the scanned image displayed on the CRT screen is Pulse generator required to move the same distance 1.9
The number of output pulses will be 17/2 of the previous number. In this way, the number of output pulses from the pulse generators 8 and 9 is increased by 1. This is because unless it is reduced to /2, the image of the part of interest will extend beyond the CRT screen. This control is performed by the control section 10. Figure 4 shows how, when an image P of a part of interest is displayed on the screen, how this part changes on the screen and is enlarged and displayed in the center according to the above operation. Two examples are shown. Note that the alphabet on the left side of the CRT screen indicates the type of button pressed. As is clear from FIG. 4, according to the apparatus of the present invention, the operator can move and enlarge the sample by simply operating the buttons while looking at the CRT screen.

Therefore, the operability is greatly improved.

Next, in order to explain the effect specific to the above-mentioned embodiment, we will explain how narrow the area is from the center of the next screen by enlarging any part within the 3/4 area at the center of the screen once. With reference to FIG. 5, it will be explained how to enlarge the image by pushing it inwards and increasing it to 1j.

FIG. 5 (I), (IF), (I[[) shows three cases as examples, and the alphabet in the figure indicates the type of button pressed. Further, S indicates the screen, 2 indicates the desired visual field (that is, the portion of the sample image of interest), and K indicates the size when Z is enlarged. To explain case (T) as an example, in order to bring the desired field of view Z to the center of the screen, press the control switch 11 and press button 8. Then, the field of view Z moves in the direction of the arrow in Figure 3.I)-
Move to the center of the screen as shown in 2. After that, CRT
The image displayed on the screen is enlarged twice, as shown in (I)-3, and occupies 1/4 of the entire screen.

Note that the example shown in (Ir) is the same as (1). however,(
In the example shown in III), the desired field of view Z is already in the center of the screen S, so when pushbutton E is pressed, it is immediately displayed ([[)
The screen will be enlarged twice as shown in -3. Although we have explained the case where the desired field of view Z is located in sections A, B, and E (see Figure 2), the same applies to the cases where the desired field of view Z is located in other sections 0°[), F, G, H, and r. The image can be placed within the central 1/4 screen with one movement and enlargement operation.

As shown in Fig. 6, let t be the total length of the sample surface initially projected, and h be the length of the part that can be included in the central 1774 screen by n times of moving and enlarging operations, then n-1. In this case, the ratio h/l is 5° x 25=75%. remaining 25
% (W in the figure) cannot fit into the central 1,74 screen when enlarged twice. If the same operation is repeated once again to increase the amount by 22-4 times, the ratio G of /l becomes t50+25+12.5=87°5%. Furthermore, if we double it again to make a total of 23-8 times, the h/l ratio becomes 50 + 25 + 12.

5+6.25=93.75%. That is, if the initial screen is multiplied by 8 (n=3), 93.75% of the entire area can be placed within the 1/4 screen at the center of the screen.

As is clear from the above explanation, in this embodiment, the part of the sample image of interest is always displayed in the center of the screen, compared to the case where the screen is divided into 9 equal parts and moved by 1/3 for enlargement. Enables efficient magnified observation.

Hence, the crowd can be doubled by one move/enlarge operation. However, it goes without saying that the magnification need not be limited to 2x. If the magnification is generally a times,
In order to efficiently enlarge and observe the area of interest while always displaying it in the center of the screen, the proportions of each area shown in FIG. 2 should be as shown in FIG. 7. (a'-1)/2 in the figure
a indicates h-vine width. The direction of movement of the sample when the push button is pressed is as shown in FIG. Note that by enlarging any part within the area where one side of the center of the screen is (3a - 3> /2a) once, it will be expanded to a narrow area in the center of the next screen.
(limited range), but the width of this limited range is (a-1)/2 as shown in Figure 9, and the magnification a
The relationship between this and the proportion of the limited range on the screen is shown in FIG. In the figure, fl is a curve showing the limited range, fl is a curve showing the width of the temple, and this curve is also a curve showing the amount of sample movement on the CRT.

It should be noted that the above-described embodiment is only one embodiment of the present invention, and many other embodiments may be adopted. For example, if you divide the screen into 9 equal parts and move the image by 1/3 with each enlargement, the center of the divided part specified by the switch will be at the center of the screen and the image will be enlarged. It is an easy-to-understand enlargement device with buttons and a map of each divided part.

Furthermore, in the implementation pAc described above, the sample stage was moved in order to move the center of the electron beam scanning area of the sample 1°, but the output value from the output horn signal source of the variable scanning width device was The center of the scanning area can be moved electromagnetically by controlling the control unit 10 according to the selected button and the magnification at that time, and this embodiment is particularly suitable for high-magnification observation.

As described in detail below, according to the present invention, it is possible to put into practical use a constant movement zoom device for a scanning electron microscope that integrates sample movement and magnification zoom, thereby significantly improving operability.

[Brief Description of the Drawings] Figure 1 is an electrical connection diagram showing one embodiment of the present invention, Figure 2 is an explanatory diagram showing the divided state of the CRT screen, and Figure 3 is an explanatory diagram showing the direction of movement of the sample. , Fig. 4 is an explanatory diagram showing an example of the operation of moving and enlarging the sample on the CRT screen, Fig. 5 is an explanatory diagram showing the movement of the field of view of the CRT screen operator, and Fig. 6 is an explanatory diagram showing the movement of the field of view of the CRT screen operator. An explanatory diagram showing the ratio, Figure 7 is C when the magnification is a
Figure 8 is an explanatory diagram showing the divided state of the RT screen, Figure 8 is an explanatory diagram showing the moving direction of the sample at this time, Figure 9 is an explanatory diagram showing the limited range of the CRT screen, and Figure 10 is the magnification a and the area occupied by the screen. FIG. 3 is an explanatory diagram showing a relationship with a ratio of a limited range. 1... Lens barrel 2... Scanning coil 3...
Drive unit 3a...Sample stage 4...Scanning width variable device 5...Scanning power source 6.7...Step motor 8.9...Pulse generator 10...Control unit 11... Control switch patent applicant JEOL Co., Ltd. Representative Patent attorney Toji Ijima - 383 = Fig. 4 M6 Fig. M9 Fig. 10 Fig. 13 (I 16 4 Tsuyoshi) 384-

Claims (1)

[Claims] a moving means for moving the center of the scanning area of the electron beam on the sample in the X direction and the Y direction relative to the sample; and means for supplying the means with an opening movement signal determined by a magnification;
a scanning width variable device that determines the amplitude of the X and Y scanning signals supplied to the scanning coil in the lens barrel; a control section that controls the moving means and the scanning width variable device; and a dividing device that divides the CRT screen by drawing lines or the like. and a control switch having a number of push buttons corresponding to the number of divisions of the dividing means.