JPS59148255A - Scanning electron microscope - Google Patents

Abstract

PURPOSE:To turn a sample up to a desired angle simply and in a short time by turning a mark to be displayed on the screen by an optional angle and turning automatically a rotary mechanism up to the angle of said mark. CONSTITUTION:A signal of a detector 13 detecting the secondary electrons generated from a sample 5 due to irradiation by electron rays 6 is fed to the cathode of a cathode-ray tube 12. Pulse motors 16I and 16R driving a tilt mechanism 2 and a rotary mechanism 4 as well as the pulse motors 16X and 16Y driving X and Y shifting mechanisms are controlled by a control device 18. The control device 18 generates a bright line display signal on the screen of the cathode-ray tube 12 basing on the signal to be fed from a scanning signal generation circuit 10. The input device 19 is provided with a bright line rotating knob 19a for turning the bright line to be displayed on the screen of the cathode-ray tube 12 on said screen, a rotation instruction button 19b instructing to turn the sample by the rotation mechanism 4 up to the indicated angle of the bright line, a sample tilting knob 19c specifying the tilt angle by the tilt mechanism 2 and the buttons 19xa-19yb shifting the sample in the directions X and Y by the XY shifting mechanism 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a scanning electron microscope capable of observing a scanning image by tilting it in any direction.

[Prior art] A scanning electron microscope has the advantage of being able to obtain a clear image even if the surface of the observation sample r1 is highly uneven, but in order to fully utilize this advantage, it is necessary to expose the sample surface to the electron beam. It is necessary to be able to tilt with the direction of the projection as an axis so that the portion corresponding to the shadow of the unevenness can be observed. In order to meet this demand, scanning electron microscopes have conventionally included a sample device as shown in FIG. That is, the side wall 1 of the sample chamber
A tilting mechanism 2 is attached to the tilting mechanism 2, and its tilting axis U is fixed. An XY moving mechanism 3 is provided on the top of the tilting mechanism 2.
However, a rotating mechanism 4 is placed on top of the rotating mechanism 4, and the observation sample 5 is attached to the rotating mechanism 4 via a holder.

Using such a trial r1 apparatus, when the sample surface relative to the sample irradiation electron beam 6 is tilted by the tilting mechanism 2, and then the sample is rotated by the sample rotation mechanism 4, the tilting axis U rotates with respect to the sample. Figure 2 (a), (b), (c
), the portion corresponding to the shadow of the unevenness displayed on the screen C can be changed.

Conventionally, the amount of rotation in such devices can be adjusted by an operator observing the screen of a push-button switch, which causes the sample to continue rotating only while the child is being pressed, and stops rotating when the button is stopped. I was operating it while doing so. However, since the rotation of the sample is mechanically driven by a motor, it has poor responsiveness to illegitimate or button operations, and it is difficult to rotate the sample to a desired angle with a single operation unless the operator is a skilled operator. There wasn't. Therefore, the goal is usually achieved through trial and error by repeatedly starting and stopping the rotation, but it takes a considerable amount of time to reach the goal, especially since it is not possible to start and stop the rotation suddenly. .

[Object of the Invention] The present invention has been made to solve these conventional drawbacks, and an object of the present invention is to provide a scanning electron microscope that can rotate a sample to a desired angle easily and in a short time. It is something.

[Structure of the Invention] The present invention includes a sample rotation mechanism, a sample r1 movement mechanism, a sample rotation mechanism, a means for two-dimensionally scanning an electron beam on a sample, and a means for scanning an electron beam in synchronization with the scanning of the electron beam. An apparatus comprising display means for displaying a sample image based on a detection signal obtained as a result of scanning of the electron beam, means for displaying a mark on both display surfaces of the display means, and means for displaying a mark on both sides of the display means; a control means for rotating the side of the sample rotating machine by φ based on a signal representing the angle φ from the reference mark of the mark; In order to prevent this, the present invention is characterized by comprising a means for moving the trial yI+ by the trial r1 moving mechanism before, after, or together with the rotation.

[Example] Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 3 schematically shows an embodiment of the present invention, in which the same components as in FIG. 1 are given the same numbers.

In the figure, 7 is an electron gun, 8 is a focusing lens for focusing the electron beam 3 and 6, and 9X and 9Y are deflection coils. A sawtooth scanning signal is supplied from a scanning signal generation circuit 10 to the deflection coils 9X and 9Y. 11X
, 11Y are amplifiers. The scanning signal from the scanning signal generating circuit 10 is also supplied to the deflection coil D of the cathode ray tube 12, and the cathode ray tube 12 is scanned in synchronization with the electron beam 6.

A secondary electron detector 13 is arranged to detect secondary electrons generated from the sample 5 by irradiation with the electron beam 6.

The signal from the detector 13 is supplied to the cathode of the cathode ray tube 12 via an amplifier 14 and a bright line signal addition circuit 15. 161.16R are pulse motors for driving the tilting mechanism 2 and rotation mechanism 4, respectively; 16X, 16
Y is a pulse motor for driving the X and Y movement mechanism. These motors 16T, 16R, 16X, 16
Yl; respectively as motor drive circuits 171.17R, 17X,
It rotates by the supply of drive pulses generated from 17Y.

Generation of drive pulses in each of these drive circuits is controlled by control signals from a control device 18. This =4- control device 18 has a storage section, arithmetic section, etc., and not only controls each drive circuit, but also controls the cathode ray tube based on a signal synchronized with scanning supplied from the scanning signal generation circuit 10. 1
A bright line display signal for displaying a bright line Q as shown in FIG. 4 on the screen of No. 2 is generated. This bright line display signal is superimposed on the signal from the detector 13 in the bright line adding circuit 15 and is supplied to the negative trifm tube 12. An input device 19 is connected to the control device 18 . This input device 19 is the fifth
As shown in the figure, there is a bright line rotation heir 19a for rotating the bright line Q displayed on both sides of the cathode ray tube 12 on the screen, and a bright line Q displayed by rotating the sample by the rotation mechanism 4.
Rotation command button 19 for commanding rotation to an angle of
b. Specimen tilt legitimate child 1 specifying the tilt angle by the tilt mechanism 2
9c, buttons 19x a, 19xb, 19y for moving the sample in the X and Y directions using the XY moving mechanism 3;
A, 19yb, etc. are provided.

In such a configuration, when the electron beam 6 is scanned on the sample 5'' by a scanning signal from the scanning signal generating circuit 10, a sample image is obtained on the cathode ray tube 12. Bright line rotating element 1
In the initial state when 9a is not operated, a horizontal bright line Q is displayed on the screen superimposed on the image as shown in FIG.

Therefore, the operator first operates the sample tilting chair 19c while observing the sample image to tilt the sample 5 at a predetermined angle, for example θ0, by the tilting mechanism 2, and presses the buttons 19xa, 19.
Move mechanism 3 by operating xb, 191/a, and 19yb.
The sample 5 is moved to a predetermined position X1. Move it to Vl. Therefore, while observing the image obtained as a result of such an operation, the bright line rotation element 19a of the input device 19 is operated to change the bright line display signal supplied from the control device 18, so that the bright line display signal supplied from the control device 18 is changed so that it is horizontal in the initial state. Rotate the bright line Q displayed on the screen around the center of the screen. Due to this rotation,
When the bright line Q is rotated by the rotation mechanism 4 until it overlaps the image part that you want to display horizontally on both sides, for example to the bright line Q1 in FIG. Order sample 5 to rotate. Assuming that the rotation angle of the bright line is φ, the control device 18 holds data representing this angle φ, so by operating the rotation command button 19h, the input device F?
When a signal instructing the rotation of the rotation mechanism 4 is supplied from the control device 19, the control device 18 sends a control signal to the drive circuit 17R to rotate the pulse motor 16R by the angle φ. As a result, the portion of the image that was displayed on the screen superimposed on the bright line Q1 is rotated by the angle φ. By the way, in many cases where the axis of rotation by the rotation mechanism 4 does not match the optical axis, if the movement mechanism 3 does not move the sample 15, the image on the sample 5 placed directly below the optical axis 7 will be removed. Point 0 (Xt,
As shown in FIG. 6, Vl) rotates to O' as the test sample 4 rotates about the rotation center R, which has moved to the positions of Xo and Vo, so that the field of view on both sides is lost. In order to prevent such a situation, the control device 18 controls the rotation center positions Xo and Vo of the sample rotation device 4 and the optical axis position X++V+.
is stored, and based on the stored data and the signal representing φ, the moving mechanism 3 moves the sample 5 in the X and Y directions by Q, x, and Qy indicated by 7- in the figure. As a result, the rotating mechanism 4
At the time when the rotation is completed, on the screen of the cathode ray tube 12, the part of the image that was displayed superimposed on the bright line Q1 before the rotation is displayed on the horizontal line, and an image without any deviation in the field of view is displayed. be done. As the test sample 5 rotates, the bright line display signal generated from the control device 18 is automatically switched to a signal for horizontally displaying the bright line, so that the bright line returns to the horizontal bright line Q.

In the above-mentioned embodiment, the movement of the sample was not performed in synchronization with the rotation operation by rotation III in order to prevent the field of view from escaping due to the rotation of the sample, but the rotation of the rotation mechanism in the X direction and By controlling the movement of the moving mechanism in accordance with the rotation of the rotating mechanism so as to cancel out the velocity component of the movement in the Y direction, it is possible to prevent the visual field from escaping not only at the end of the rotation but also during the entire rotation process. I can do it.

Furthermore, in the above-described embodiment, a bright line was used as a mark for specifying the rotation angle of the sample, but a cross-shaped mark, for example, may also be used. Alternatively, the bright line may be displayed in place of the bright line.

[Effect] As mentioned above, in the present invention, the mark displayed on both sides is rotated by an arbitrary angle, and the rotation mechanism 4 is automatically rotated by the angle of this mark.
Since the display mm of the marks can all be changed with good responsiveness by electrical control, the sample can be rotated to a desired angle easily and in a short time.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the sample device of a scanning electron microscope, Fig. 2 is a diagram for explaining that the tilting shaft is rotated by rotation by a rotation mechanism, and Fig. 3 is an embodiment of the present invention. Figure 4 is a diagram to explain the changes in bright lines displayed on the cathode ray tube, Figure 5 is a diagram to explain the input device, and Figure 6 is the rotation of the trial. FIG. 2 is a diagram for explaining the deviation of the visual field based on 1: Side wall, 2: Tilt mechanism, 3: Moving tR, 4: Rotating mechanism, 5: Sample, 6: Electron beam, 7: Electron gun, 8: Focusing lens, 9X, 9Y: Deflection coil, 10: Scanning signal Generation circuit, 12: Cathode ray tube, 13: Secondary electron detector, 15: Bright line signal addition circuit, 16■. 16R, 16X, 16Y: Pa)l/S-E-Yu, 1
7■. 17R, 17X, 17Y: drive circuit, 18: control device,
19: Manual operation, 19a: Emission line rotation heir, 19b: Rotation command button, 19C: Sample tilt heir, 19xa, 19
xb, 19ya, 19yb: sample moving chair, U: tilt axis, C: screen, l: optical axis, Q, Ql: emission line. Patent Applicant JEOL Ltd. Representative Ito -fu 11- "" ) 272- f → Toka

Claims (1)

[Claims] a sample tilting mechanism, a sample moving mechanism, a sample rotation mechanism, a means for two-dimensionally scanning an electron beam on the sample, and a means for scanning in synchronization with the scanning of the electron beam; An apparatus comprising a display means for displaying a sample image based on a detection signal obtained, a means for displaying a mark on a display screen of the display means, a means for arbitrarily rotating the mark, and a reference for the mark. control means for rotating the sample rotation mechanism by φ based on a signal representing the angle φ of the sample rotation mechanism; A scanning electron microscope characterized by comprising means for moving a sample by the sample moving mechanism.