JPS6314810B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for easily searching a field of view in a transmission imaging electron microscope or a scanning electron microscope.

In a transmission electron microscope, an electron beam transmitted through a sample is imaged onto a phosphor plate by an imaging lens system. In order to move the field of view of this microscope image,
Usually, a sample moving mechanism is used that mechanically moves the position of the sample to which the electron beam is irradiated. The sample movement mechanism is operated manually or by using a pulse motor, but as the observation magnification increases, the amount of sample movement becomes extremely small, and the movement must be done carefully and in small increments to avoid vibrations. Moreover, since the amount of movement of the sample increases as the observation magnification decreases, a considerable amount of time is required to move the field of view. Therefore, the so-called field-of-field search operation for searching for a target location on an observation sample is a troublesome operation, as the field-of-view must be moved many times. On the other hand, another method for moving the field of view is to use a deflection coil provided at an appropriate position within the imaging lens system, and to direct only the electron beam that has passed through a specific part of the sample to the deflection coil on the optical axis within the imaging lens system. There is a method using a deflection movement mechanism consisting of a means for supplying a deflection current so as to guide it to the vicinity, and this method is used especially for the purpose of smoothly moving a minute sample in a high-magnification image. (For details, refer to Japanese Patent Publication No. 48-33903.) However, as the observation magnification decreases, even with this method of electric field movement, electrons that are far away from the optical axis of the imaging lens system in the sample-transmitting electron beam This method requires the use of lines, which has the disadvantage of increasing image distortion due to the effects of lens aberration.
It was almost never used to search the field of view in low-magnification images.

The present invention aims to eliminate the troublesome operation of searching the field of view as described above, and provides a sample moving mechanism that moves the field of view of an electron microscope by moving a sample that is irradiated with an electron beam, and Alternatively, in an apparatus equipped with a deflection movement mechanism that moves the field of view by deflecting an electron beam transmitted through the sample, means for storing the position of the field of view obtained by operating the deflection movement mechanism with respect to the optical axis, and a start signal. generating means, and turning off the deflection by the deflection movement mechanism based on a signal supplied from the start signal generating means, and based on a signal representing the position of the visual field at the time of the start stored in the storage means. The present invention is characterized by comprising means for controlling the movement of the sample by the sample movement mechanism so as to reproduce the obtained field of view.

The drawing is a schematic diagram showing an embodiment of an apparatus in which the present invention is applied to a transmission electron microscope. In the figure, reference numeral 1 represents a thin film sample, onto which an electron beam 3 emitted from an electron gun 2 is irradiated in parallel through a converging lens 4. The electron beam transmitted through the sample 1 forms a microscopic image on a fluorescent plate 8 by an imaging lens system consisting of an objective lens 5, an intermediate lens 6, and a projection lens 7. The image magnification of this microscope image can be changed by operating the magnification specifying means 9 and changing the output of the lens power supply 10 of the imaging lens system. This is done by operating the knobs on the operation panel 11 shown in . For example, if you want to move the microscope image displayed on the fluorescent plate 8 left and right in the X direction, use the knob 12X.
Or press 13X a number of times according to the amount of movement, and if you want to move up and down in the Y direction, press knob 14Y,
By pressing 15Y a number of times according to the amount of movement, the direction and amount of movement of the visual field are designated. The signal generated by pressing the knob is sent to the central control circuit 17 via the signal generating circuit 16, and the circuit 17, together with the signal from the magnification specifying means 9, determines which value the outputs of the deflection power supplies 18X and 19Y should be set to. Based on the result, the deflection power supplies 18X, 19Y
supply control signals to the Deflection power supply 18X, 19Y
are two-stage deflection coils 20X, 21X and 20, respectively.
By supplying a DC deflection current to Y and 21Y, the electron beam passing through a specific part of the sample 1 is guided to the optical axis of the imaging lens system below the intermediate lens, and is imaged onto the phosphor plate. As described above, this electrical visual field movement operation is quick and easy, so it is extremely convenient for moving the visual field many times to search for visual fields.

When the visual field search operation by electrical visual field movement is completed in the manner described above, the knob S on the operation panel 11 is pressed. When the signal from the signal generation circuit 16 generated by pressing the knob S is applied to the central control circuit 17, the value of the signal supplied to the deflection power supplies 18X and 19Y is stored in the memory, and
Supplying a reset signal to the deflection power supplies 18X and 19Y, the deflection coils 20X, 20Y, 21X, 21Y
Turn off electrical field movement. At the same time, the information regarding the electrical field of view movement stored in the memory is transferred to the X-direction driving pulse motor 23X and the Y-direction driving pulse motor 2 of the sample moving device 22.
4Y, and the converted control signal is supplied to pulse motors 23X and 24Y. This conversion is performed so that the direction and amount of field movement due to electrical field movement and mechanical movement of the sample match, so excluding the short period immediately after pressing the S button, the fluorescent light before and after pressing the S button is 8
The upper field of view remains constant. However, the distortion and aberration of the microscope image have been improved compared to before pressing button S, making it suitable for photography and detailed observation with the naked eye.

As described above, in the present invention, by providing an instantaneous switching mechanism for moving the field of view using electron beam deflection means and moving the field of view using mechanical sample movement, the operation of searching the field of view in an electron microscope can be performed quickly and easily. It becomes possible to do so.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Sample, 2... Electron gun, 3... Electron beam, 4... Converging lens, 5... Objective lens, 6... Intermediate lens, 7...
Projection lens, 8... Fluorescent plate, 9... Magnification specifying means, 1
0...Lens power supply, 11...Operation panel, 12X, 1
3X, 14Y, 15Y...Knob, 16...Signal generation circuit, 17...Central control circuit, 18X, 19Y...Deflection power supply, 20X, 20Y, 21X, 21Y...Deflection coil, 22...Sample moving device, 23X, 23Y...
pulse motor.

Claims (1)

[Claims] 1. A device equipped with a sample moving mechanism that moves the field of view of an electron microscope by moving the sample irradiated with an electron beam, and a deflection moving mechanism that moves the field of view by deflecting the electron beam that irradiates the sample or the electron beam that transmits the sample. means for storing the position of the field of view obtained by operating the deflection movement mechanism with respect to the optical axis;
a start signal generating means, and a signal that turns off the deflection by the deflection movement mechanism based on the signal supplied from the start signal generating means, and that represents the position of the visual field at the time of the start, which is stored in the storage means. A field of view setting device for an electron microscope, comprising means for controlling movement of a sample by the sample moving mechanism so as to reproduce the obtained field of view based on the field of view obtained above.