JPH0521824Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a charged particle beam device that is most suitable for use in a microscope or drawing device that uses a charged particle beam such as an electron beam or an ion beam.

[Prior Art] In a charged particle beam device such as an electron microscope or an ion beam lithography device, a charged particle beam from a charged particle beam generation source is accelerated and irradiated onto a target such as a sample or a material. FIG. 2 shows an electron beam accelerating section in an electron beam device, in which 1 is an electron generating cathode, 2 is a Wehnelt electrode, and 3 is an anode at ground potential. An accelerating voltage is applied between the cathode 1 and the anode 3 by a high voltage power supply 4. 5 is a cylindrical insulator; one end of the insulator 5 is fixed to the anode 3, the other end is fixed to the electrode 7 having the same potential as the cathode, and the area surrounded by the insulator is placed in a high vacuum. It is being exhausted.
In such a configuration, electrons generated from the cathode 1 are accelerated by the anode 3, and the electron beam passing through the opening of the anode 3 is irradiated onto a target placed below the anode.

[Problems to be Solved by the Invention] Incidentally, although part of the electron beam accelerated toward the anode 3 passes through the opening of the anode 3, most of it collides with the anode. As the electron beam collides with the anode, reflected electrons having energy comparable to that of the accelerated incident electron beam are generated from the anode. The reflected electrons radiate in all directions, and as a result, the reflected electrons directed toward the insulator 5 collide with and accumulate there, causing the surface of the insulator to be charged. Due to the charging of the surface of the insulator, the potential distribution on the surface of the insulator changes, and a micro discharge occurs at this changed portion. This minute discharge triggers a creeping discharge that travels along the insulator surface between the cathode 1 and the anode 3.

Therefore, as shown in FIG. 3, it has been considered to coat the surface portion of the insulator 5 with a high-resistance material. In this case, the reflected electrons directed toward the insulator 5 are immediately discharged through the high-resistance material on the surface of the insulator, so that the insulator is no longer charged, making it possible to prevent creeping discharge on the surface of the insulator. However, since the insulator also plays a role as a vacuum partition, the insulator 5 and the electrode 3,
7 must be welded to prevent vacuum leakage. Welding for vacuum sealing between the insulator and the electrode must be performed at a considerably high temperature, and as a result, due to the high temperature during welding,
The electrode metal will diffuse into the coated high-resistance material, and the resistance value of the high-resistance material will drop significantly, especially in the portions near the electrodes 3 and 7 at both ends of the insulator. Therefore, the high-resistance material is unable to maintain a high resistance value during manufacture, and before creeping discharge occurs, electrodes 3 and 7 become almost short-circuited, causing a high voltage to be applied between the electrodes. It becomes impossible to apply any voltage. Moreover, the insulator 5 as a partition wall member
Even when the entire structure is made of a high-resistance material, the resistance value decreases in the same manner as described above because welding is performed under high temperature for vacuum sealing.

This invention was made in view of the above points,
It is an object of the present invention to provide a charged particle beam device that can prevent creeping discharge from occurring.

[Means for solving the problem] The charged particle beam device based on the present invention has a first and a second
a means for applying a high voltage between the two electrodes, and a partition member disposed around the charged particle beam passage between the first and second electrodes, In a charged particle beam device configured to accelerate or focus a charged particle beam, a cylindrical member made of a high-resistance material is disposed inside the partition member, spaced apart from the partition member, and It is characterized in that the cylindrical member and both electrodes are electrically connected.

[Operation] The charged particle beam accelerated between the first electrode and the second electrode collides with the second electrode to generate reflected electrons. The generated backscattered electrons are emitted in each direction, but inside the insulating partition member placed around the path of the charged particle beam between the two electrodes, there is a cylinder made of a high-resistance material. Since the cylindrical member is arranged, the charged particle beam directed towards the partition member collides with the cylindrical member and is transmitted along the surface portion of the cylindrical member to be discharged. As a result, creeping discharge on the surface of the partition member can be prevented. can.

[Embodiment] An embodiment of the present invention will be described below in detail based on the accompanying drawings.

FIG. 1 shows an electron beam apparatus embodying the present invention, and the same parts as in FIGS. 2 and 3 are given the same numbers and their explanations will be omitted. The difference between the device shown in FIG. 1 and the conventional device shown in FIG. 2 is that a cylindrical member 8 made of a high-resistance material is placed inside an insulator 5 as a vacuum partition member. be. The cylindrical member is fixed to the anode 3 and the electrode 7 by welding, and the member 8 and both electrodes 3 and 7 are electrically connected. With this configuration, the anode 3 has
Even if the backscattered electrons generated by the collision of the accelerated electron beams head in the direction of the insulator 5, the backscattered electrons collide with the cylindrical member 8 and are immediately discharged through the cylindrical member, which is a high-resistance material. Therefore, the insulator is no longer charged, and creeping discharge on the surface of the insulator can be completely prevented. Further, the role of the vacuum partition wall is played by the insulator 5, and the cylindrical member 8
There is no need to consider vacuum leakage when fixing the cylindrical member 8 to the electrode.
It is sufficient if both ends of the tube are in contact with the electrode metal, and the electrode metal does not diffuse into the cylindrical member at all.
Therefore, the resistance value of the cylindrical member 8 can be maintained at the value when the member was manufactured. Note that a hole 9 is bored in a part of the cylindrical member 8 to increase the exhaust conductance of the space between the cylindrical member 8 and the insulator 5.

Although the present invention has been described in detail above, the present invention is not limited to the embodiments described above and can be modified in many ways. For example, the present invention can be used in an electrostatic lens part that focuses a charged particle beam by applying a high voltage between two electrodes. Furthermore, although the explanation has been given using an electron beam device as an example, the present invention can also be applied to an ion beam device.

[Effects] As detailed above, the present invention can prevent creeping discharge in the partition wall disposed in the acceleration or focusing portion of the charged particle beam, and can maintain the normal operation of the charged particle beam device for a long time. can be maintained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an electron beam device that is an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing an example of a conventional electron beam device. 1... cathode, 2... Wehnelt electrode, 3...
Anode, 4... High voltage power supply, 5... Insulator, 6...
High resistance material, 7... Electrode, 8... Cylindrical member, 9...
...hole.

Claims (1)

[Claims for Utility Model Registration] (1) First and second electrodes, means for applying a high voltage between the two electrodes, and a charged particle beam path between the first and second electrodes. In a charged particle beam device having a partition wall member disposed around the electrodes and configured to accelerate or focus a charged particle beam between the electrodes, a high-voltage beam is provided inside the partition member and spaced apart from the partition wall member. A charged particle beam device characterized in that a cylindrical member made of a resistive material is arranged, and the cylindrical member and both electrodes are electrically connected. (2) The charged particle beam device according to claim 1, wherein the cylindrical member is provided with a hole.