JPS6363110B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zoom wobbler for facilitating observation of a sample in a scanning electron microscope or the like.

In devices such as scanning electron microscopes and ion microanalyzers, a finely focused charged particle beam irradiates the sample surface and at the same time scans a certain area to detect various signals obtained from the sample. . The detection signal is synchronized with the scanning.
It is used as a brightness modulation signal for an image display device such as a CRT, and a brightness modulated scanned image is displayed on the image display device. When attempting to magnify and observe a small area within a wide field of view with this type of device, the area is brought to the center of the screen (or within a predetermined frame), first magnified to the next magnification, and then further magnified. The image of the desired part was obtained by repeating the cumbersome moving and enlarging operation of bringing the part to the center of the screen and enlarging it to the next magnification. Therefore, it takes an enormous amount of time and effort for the operator to bring the desired field of view to the center of the screen.

The present invention has been made in view of the above points, and includes a switch for starting the zoom operation, and a switch that changes the scanning width of the electron beam that scans the sample at regular intervals based on the zoom operation start signal from the switch. a scanning means for automatically and repeatedly scanning the sample while decreasing the amount by a predetermined amount; a direction indicating means for indicating the moving direction of the field of view in the sample image displayed by the scanning; and a sample moving means for automatically moving the sample in a direction corresponding to the moving direction of the field of view at a speed that becomes slower in accordance with the automatic reduction of the scanning width. This is a zoom watch that can bring the desired field of view to the center of the screen.

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

FIG. 1 is an electrical configuration diagram showing an embodiment of the present invention. In this example, in order to simplify the explanation, since the image rotation effect by the objective lens is negligible, the direction of the field of view of the sample image displayed on the display device and the actual direction of the sample will be A case will be explained in which the deviation in the direction of is negligible. 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. Reference numeral 4 denotes a scanning width variable device that drives the scanning coil 2, and the magnification of the displayed image can also be changed by the scanning width variable device 4. For example, if you reduce the scan width to 1/2,
The magnification will be doubled. 5 is a scanning power source that supplies scanning voltage to the scanning coil 2; 6 and 7 are step motors that are attached to the drive unit 3 and move the sample stage 3a in the X and Y directions; 8 and 9 are these step motors 6; , 7. This is a pulse generator that sends drive pulses to

10 is a scanning width variable device 4 and pulse generators 8 and 9
This is a control unit that controls the As the control unit 10, for example, a microcomputer is used.
11 is the on/off switch for the zoom watch, 12
1 is a minimum magnification setting switch, 13 is a zoom number setting switch, and 14 is a zoom time setting switch.
15 is a joystick connected to the control section 10. The joystick 15 is arranged side by side with a CRT screen 20, which will be described later, in order to improve operability (see FIG. 3). The control section 10 provides the pulse generators 8 and 9 with a control signal for moving the sample in a direction exactly opposite (180 degrees opposite) to the direction in which the joystick 15 falls. The sequence for moving the sample in the exact opposite direction is given in advance by a program. Furthermore, this control section 10 is capable of executing a control operation such that the sample moving speed is reduced in response to an increase in the magnification of the zoom wobbler. For example, if the magnification is doubled, the sample movement speed will be halved. In this way, the higher the magnification, the slower the moving speed of the sample is because when the magnification is doubled, the moving speed on the CRT screen 20 is also doubled.
This is because, in order to maintain the same moving speed on the CRT screen 20, the moving speed itself needs to be reduced to 1/2. In addition, to reduce the movement speed,
The frequency of the pulses applied to the step motors 6 and 7 may be reduced.

The operation of the zoom wobbler configured in this way will be explained using FIGS. 2 and 3.

FIG. 2 is an explanatory diagram of the operation of the zoom wobbler shown in FIG. 1. The horizontal axis of the figure shows time, and the vertical axis shows magnification, and the higher the vertical axis, the higher the magnification. In the figure, Z ₁ , Z ₂ ... are the first zoom,
The second time... is shown. _A1 is the zoom start point, _K1 is the minimum magnification, and the value is set by the minimum magnification setting switch 12. For example, _K1 is set up to 1000 times. The number of steps during the first zoom _Z1 indicates the zoom number, and the value is set by the zoom number setting switch 13. For example, the zoom number is 2 to 20.
Steps are set. Further, the step width T is the zoom time, and its value is set by the zoom time setting switch 14. For example, the zoom time is 1
The time is set to 20 seconds. Various information set by these setting switches is read into the control section 10.

When the on-off switch 11 is turned on, the control unit 10 receives this as a zoom start signal, and
Start zoom operation. If the joystick 15 is set up as shown in FIG. 3a and the sample is not moved, the sample that is not at the center of magnification of the zoom wobbler (the center of the drawing) will move eccentrically on the screen as the magnification automatically increases. Then, the joystick 15 is folded down as shown in FIG. 3b. Control unit 10
knows the direction in which the joystick 15 has fallen, and in order to move the sample in the opposite direction to this direction,
A control signal to that effect is given to the pulse generators 8 and 9. Upon receiving this, the pulse generators 8 and 9 supply predetermined pulse outputs to the step motors 6 and 7, and move the sample stage 3 in the direction exactly opposite to the direction in which the joystick 15 falls. Accordingly, the sample moves on the CRT screen 20 toward the center of the magnification of the zoom wobbler as shown in FIG. 3b, and the sample comes to the center of the magnification as shown in FIG. 3c. Furthermore, the control section 10
As the magnification increases, a control signal is applied to the pulse generators 8 and 9 to slow down the movement speed of the sample stage 3, so even if the magnification increases, the movement speed of the sample on the CRT screen 20 remains constant. It has become constant.

According to the embodiment described above, since the joystick is used, a high-magnification image of a desired portion of the sample can be obtained simply by tilting the joystick 15 in the direction of movement of the field of view.

In the above-described embodiment, the direction of movement of the field of view is displayed using a joystick, but in place of the joystick, there are push buttons for indicating the horizontal (left and right) directions of the display screen and vertical (up and down) directions.
A push button for direction indication may also be used.

Additionally, if there is a discrepancy between the direction of the sample image displayed on the CRT screen and the actual direction of the sample, it is necessary to move the sample in the direction that corresponds to the direction of movement of the field of view indicated by the direction indicating means. Because there is
In this case, the control section may generate a control signal for moving the sample in this direction.

In addition, always zoom at a constant magnification, create a frame with a size of 1/(magnification) on the CRT screen as shown in Figure 4, and hold the sample within the frame when moving the sample. If it is set so that the sample is placed in the magnified screen, the operability for placing the sample within the magnified screen can be further improved. In this case, the frame may be made by bright lines on the CRT screen, or it may be made by drawing lines on a separate transparent plate and attached to the CRT screen.

As described in detail above, according to the present invention, it is possible to realize a zoom watcher that can easily move the target field of view to the center of the screen in a short time.

[Brief explanation of drawings]

FIG. 1 is an electrical configuration diagram showing an embodiment of the present invention, FIGS. 2 and 3 are diagrams explaining its operation, and FIG. 4 is a diagram showing the frame of a CRT screen. DESCRIPTION OF SYMBOLS 1... Lens barrel, 2... Scanning coil, 3... Drive unit, 3a... Sample stage, 4... Scanning width variable device, 5...
...Scanning power supply, 6,7...Step motor,8,
9...Pulse generator, 10...Control unit, 11...
On/off switch, 12... Minimum magnification setting switch, 13... Zoom number setting switch, 14... Zoom time setting switch, 15... Joystick, 20... CRT screen.

Claims (1)

[Claims] 1 A switch to start the zoom operation,
scanning means for automatically and repeatedly scanning the sample while decreasing the scanning width of the electron beam that scans the sample by a predetermined amount at fixed time intervals based on a zoom operation start signal from the switch; a direction indicating means for instructing the moving direction of the field of view in the sample image, and a direction corresponding to the moving direction of the field of view instructed by the direction indicating means at a speed that decreases in accordance with the automatic reduction of the scanning width. A zoom mover equipped with a sample moving means for automatically moving the sample.