JPS6321886Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a transmission scanning image observation device that can easily select and observe a bright field image and a dark field image of electrons transmitted through a thin film sample.

Conventionally, when observing a transmitted image, an electron beam detector is fixed below a sample, and an electron beam deflection coil is placed between the sample and the detector, and when observing a bright field image, the deflection coil is The configuration is such that the excitation is turned off so that only the central beam is incident on the detector, and when observing a dark field image, an appropriate current is applied to the deflection coil to cause any diffracted beam to be incident on the detector.

Using such a device, it is possible to electrically switch between bright and dark field images, making it easy to handle, but it requires placing a deflection coil close to the sample stage, which limits the movement, tilting, and rotation of the sample. will be given.

It is an object of the present invention to provide an apparatus that can easily switch between a bright-field image and a dark-field image without using the above-mentioned obstacles.

Therefore, the present invention includes an electron lens for narrowly focusing an electron beam, a sample stage placed after the electron lens and capable of holding a thin film sample, and a sample stage for directing the electron beam focused by the electron lens onto the sample. A scanning means for dimensionally scanning, a detector for detecting electrons transmitted through the sample as a result of the irradiation, a display device to which an output signal of the detector is supplied as a luminance signal, and arranged to surround an incident part of the detector. movement for moving the detector and the fluorescent screen together in a direction perpendicular to the axis of the electron beam in order to switch the image taken into the detector between a transmission scanning dark field image and a transmission scanning bright field image; The method is characterized by comprising an observation window provided on the sample for observing the surface on the fluorescent screen.

The embodiment shown in the drawings will be described below. In the figure, 1
is the sample chamber, and the inside is evacuated to a high vacuum. An objective lens 2 is mounted on top of this sample chamber, and a focusing lens 3 is further fixedly installed on top of the objective lens 2. An electron gun is placed on the focusing lens, and the electron beam emitted from the gun is narrowly focused by the focusing lens and the objective lens 2. 4a and 4b are deflection coils disposed in the objective lens 2, to which horizontal and vertical sawtooth wave signals are supplied from a scanning power source (not shown), and scan the electron beam in the X and Y directions. A first sample stage 5 is placed directly below the objective lens 2, with thin film samples 6a,
6b and 6c are held. This sample stage is connected to a drive mechanism 7 outside the sample chamber, and can move the sample arbitrarily within a plane perpendicular to the electron beam axis. A second sample stage 8 is connected to a drive mechanism 9 like the first stage, and can be moved arbitrarily within a plane perpendicular to the electron beam axis. This stage is far away from the objective lens, and the sample is set on this stage during observation or analysis that requires a long working distance. In this embodiment, this stage is used, a transmitted electron detector 10 is fixed thereto, and the position of the detector can be adjusted using a drive mechanism 9. A fluorescent plate 11 is placed on the detector, and a scintillator 12 is provided in the center thereof. This scintillator converts incident electrons into light, and this converted light is detected by a detector 10 such as a photomultiplier tube. The output of this detector is supplied to a display device as an image signal. Reference numeral 13 denotes an observation window provided on the upper surface of the sample chamber 1 through which the pattern on the fluorescent plate can be observed.

Assume that the thin film sample is mounted on the stage 5 in such a configuration, and the part 6b is irradiated with an electron beam as shown in the figure. The transmitted electrons from the sample are the central beam EB ₁
and diffracted beams EB ₂ , EB ₃ , ... are divided into fluorescent plate 1
Project onto 1. Therefore, by operating the drive mechanism 9 so that the center beam EB ₁ is incident on the scintillator 12, bright field observation is possible, and by making the desired diffracted beam, for example EB ₂ , incident on the scintillator 12, dark field observation is possible. Images can be observed.
When selecting the central beam and the diffracted beam, the pattern on the fluorescent plate 11 is viewed through the observation window 13 and the desired beam is made incident on the scintillator 12.

In the above embodiment, the fluorescent screen and the detector are placed on the second sample stage in order to move them together. A moving mechanism may be provided separately.

As is clear from the above description, according to the present invention, it is possible to switch between a transmission scanning bright-field image and a transmission scanning dark-field image without installing an obstacle such as a deflection coil. The sample held on the sample stage 5 can be observed at a large tilt without sacrificing the advantage of being able to switch between the dark field image and the transmission scanning dark field image.

[Brief explanation of drawings]

The accompanying drawings are cross-sectional views showing one embodiment of the present invention. 1: sample chamber, 2: objective lens, 3: focusing lens, 4a, 4b: deflection coil, 5: first sample stage, 6a, 6b, 6c: thin film sample, 7: drive mechanism, 8: second sample stage, 9: Drive mechanism, 1
0: detector, 11: fluorescent plate, 12: scintillator, 13: observation window.

Claims (1)

[Scope of utility model registration request] An electron lens for narrowly focusing an electron beam, a sample stage placed after the electron lens and capable of holding a thin film sample, and scanning the electron beam focused by the electron lens two-dimensionally on the sample. a scanning means, a detector for detecting electrons transmitted through the sample as a result of the irradiation, a display device to which an output signal of the detector is supplied as a luminance signal, a fluorescent plate disposed surrounding an incident part of the detector; a moving means for integrally moving the detector and the fluorescent screen in a direction perpendicular to the axis of the electron beam in order to switch the image taken into the detector between a transmission scanning dark field image and a transmission scanning bright field image; A transmission scanning image observation device comprising an observation window provided in a sample chamber for observing.