JPH0955180A - Electron beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the emitter of a field emission type electron gun installed in an electron gun chamber from being broken without deteriorating the degree of vacuum (increasing the pressure) in a lens barrel even when a sample holder is inserted into or removed from a sample chamber. SOLUTION: When a sample hold section 11 is not located at the prescribed position on the optical axis or near the optical axis, a sluice valve 6 is closed. When the sample hold section 11 is moved near to the optical axis by the movement of a sample holder 10, it is brought into contact with a switch 12, and the switch 12 is tuned on to send a signal. A control device 13 sends an instruction to a sluice valve driving mechanism 7 based on the signal, and the sluice valve 6 is opened. When the sample holder 10 is moved, the sample hold section 11 is moved toward a spare chamber 9 from the optical axis. The switch 12 is separated from the sample hold section 11 during this movement, the switch 12 is tuned off, and no signal is sent to the control device 13. The control device 13 sends an instruction to the sluice valve driving mechanism 7, and the sluice valve 6 is closed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electron beam apparatus equipped with a field emission electron gun.

[0002]

2. Description of the Related Art In electron beam devices such as electron microscopes, field emission type electron guns are often used as electron guns. This field emission electron gun has an electron source called an emitter and an extraction electrode for extracting an electron from the emitter. In such a field emission electron gun, when the electron is emitted from the emitter, how The issue is to sustain electron emission stably for a long time without damaging the electron beam. The best solution to this problem is to maintain the vacuum level around the electron gun as much as possible (reduce the pressure) to maintain that vacuum level, that is, the ultra-high vacuum. It is no exaggeration to say that it is to hold.

[0003]

However, for example, in an electron microscope, an electron gun chamber is usually provided on the top of a lens barrel, and a sample chamber is provided below the electron gun chamber with a focusing lens installation space interposed therebetween. The sample holder is inserted into or removed from the sample chamber each time the sample is replaced. The degree of vacuum inside the lens barrel deteriorates (pressure increases) as the sample holder moves in and out,
Therefore, the emitter of the field emission type electron gun installed in the electron gun chamber may be damaged.

The present invention has been made in view of the above circumstances, and provides a novel electron beam apparatus.

[0005]

An electron beam apparatus according to a first aspect of the invention is an electron beam apparatus having an electron gun chamber and a sample chamber, and is based on the position of a sample holder that is inserted into and removed from the sample chamber. It is characterized in that a sluice valve provided between the electron gun chamber and the sample chamber is opened and closed.

An electron beam apparatus according to the second aspect of the invention is an electron beam apparatus having an electron gun chamber and a sample chamber,
When the sample holder that is put in or taken out of the sample chamber is located on or near the optical axis, a sluice valve provided between the electron gun chamber and the sample chamber is opened, and the sample holder is turned on. It is characterized by the provision of a sluice valve opening / closing mechanism that closes when not located on the axis or near the optical axis.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 schematically shows an electron microscope as an example of the present invention. In the figure, reference numeral 1 denotes a lens barrel, and an electron gun chamber 3 provided with a field emission type electron gun 2 is provided on the top thereof. Reference numeral 4 is a focusing lens provided directly below the electron gun chamber 3. A sample chamber 5 is provided with a gate valve 6 between the sample chamber and the focusing lens arrangement space, and the gate valve is operated by a gate valve drive mechanism 7. A preparatory chamber 9 is provided in the sample chamber 5 via a gate valve 8. The preliminary chamber and the sample chamber 5 are evacuated by an exhaust pump (not shown), and the sample holder 10 at the tip thereof is positioned in the preliminary chamber 9 by the movement of the sample holder 10. After the valve 8 is closed in this state, the preliminary chamber is leaked, and the sample holder 10 is moved to pull the sample holder 11 into the atmosphere to replace the sample. Then, the sample holder is pushed into the preliminary chamber 9 by moving the sample holder 10, the preliminary chamber is evacuated to a predetermined pressure, the valve 8 is opened, and the sample holder 10 is moved by moving the sample holder 10. The part is located at the center of the sample chamber 5, that is, on the optical axis. The switch 12 is turned on when the sample holder 11 is moved and comes close to the optical axis, and is turned on by being brought into contact with the sample holder, and is turned off when the sample holder 11 is moved and separated from the vicinity of the optical axis. It is a switch made to do. Reference numeral 13 is a control device for controlling the operation of the sluice valve drive mechanism by a signal from the switch. A projection lens arrangement space, an observation room, a camera room and the like are provided below the sample room 5.

The operation of such a configuration will be described below.

First, the sample holder 11 that has undergone sample exchange in the atmosphere is thrust into the preliminary chamber 9 by the movement of the sample holder 10, the preliminary chamber is evacuated to a predetermined pressure, and then the valve 8 is opened, By moving the sample holder 10, the sample holder 11 is positioned at the center of the sample chamber 5, that is, on the optical axis. During this time, when the sample holding unit 11 is not between the optical axis and the predetermined position near the optical axis, the gate valve 6 is in the closed state. On the other hand, in such a movement, when the sample holder 11 comes in the vicinity of the optical axis and the switch 12 is touched, the switch is turned on. Then, a signal flows, and the control device 13 causes the gate valve drive mechanism 7 to operate according to the signal.
To send the command to open the gate valve 6. Under this condition, the sample in the sample holder 11 located on the optical axis is irradiated with the electron beam from the electron gun 2 focused by the focusing lens 4, and the transmitted electrons are projected by a projection lens (not shown) in an observation room. An image is formed on a fluorescent plate (not shown) (not shown), and a transmission electron image of the sample is observed. On the other hand, when exchanging the sample, the sample holder 10 is moved and the sample holder 11 is moved from the optical axis toward the preliminary chamber 9. During this movement, the switch 12 is removed from the sample holder.
Is released, the switch is turned off, and no signal flows to the control device 13. Therefore, the control device sends a command to the sluice valve drive mechanism 7 to bring the sluice valve 6 into a closed state. In this state, when the sample holder 11 moves toward the preliminary chamber and enters the preliminary chamber, the gate valve 8 closes. Then, the preliminary chamber is leaked, and the sample holder 11 is pulled into the atmosphere by the movement of the sample holder 10 to replace the sample.

As described above, when the sample holder is not located on the optical axis and near the optical axis, the electron gun chamber 3 and the sample chamber 5 are arranged.
The sluice valve 6 provided between the two is automatically closed. Therefore, even if the sample holder is put in or taken out of the sample chamber every time the sample is exchanged, the degree of vacuum in the lens barrel does not deteriorate (the pressure increases), and therefore it is installed in the electron gun chamber. The damage of the emitter of the field emission type electron gun is prevented.

[Brief description of drawings]

FIG. 1 schematically shows an electron microscope as an example of the present invention.

[Explanation of symbols]

 1 lens barrel 2 field emission type electron gun 3 electron gun chamber 4 focusing lens 5 sample chamber 6 sluice valve 7 sluice valve drive mechanism 8 sluice valve 9 preparatory chamber 10 sample holder 11 sample holder 12 switch 13 controller

Claims (2)

[Claims] 1. An electron beam apparatus having an electron gun chamber and a sample chamber, wherein a sluice valve is provided between the electron gun chamber and the sample chamber based on the position of a sample holder that is moved into and out of the sample chamber. Electron beam device designed to open and close. 2. An electron beam apparatus having an electron gun chamber and a sample chamber, wherein the electron gun chamber and the sample chamber are located when a sample holding section which is put in and out of the sample chamber is located on or near the optical axis. An electron beam apparatus provided with a sluice valve opening / closing mechanism for opening a sluice valve provided between the sluice valve and the sample holder and closing the sluice valve when the sample holder is not located on or near the optical axis.