JPH0658794B2 - Charged particle beam device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a charged particle beam device such as an electron microscope, and in particular,
The present invention relates to a charged particle beam device provided with a mechanical axis alignment mechanism for a charged particle beam source.

[Prior Art] Conventionally, as a charged particle beam apparatus, an electron microscope having a configuration as shown in FIG. 2 is known. In FIG. 2, 1 is a multi-stage accelerating tube, 2 is an accelerating electrode, 3 is a high-voltage insulator, 4 is a base,
5 is an electron gun, 6 is a filament, 7 is a Wehnelt, 8 is an upper support plate, 9 is an arm, 10 is a bellows, 11 is an electron gun holding part, 12 is an insulating rod, 13 is a motor, 14 is an axis alignment mechanism, and 15 is A dividing resistor, 16 is a deflection coil, and 17 is a focusing lens.

The multistage accelerating tube 1 in which the accelerating electrodes 2 and the high-voltage insulators 3 are alternately stacked has a base 4 and a Wehnelt potential (-
It is provided so as to be sandwiched by the upper support plate 8 located at (HT). An electron gun holder 11 is provided on the upper support board 8 via a bellows 10, and the electron gun 5 is fixed on the holder 11.

In the apparatus having such a configuration, in order to cause the electron beam emitted from the electron gun 5 to enter the focusing lens 17 through the accelerating tube 1, the mechanical alignment of the electron gun 5 and the electrical alignment by the deflection coil 16 are performed. Done.

By the way, in an ultra-high voltage electron microscope whose accelerating voltage is as high as 1000 KV, the length of the accelerating tube is as long as 2 meters, and unless the mechanical alignment of the electron gun is accurately performed, the electrons emitted from the electron gun are emitted. The line cannot sufficiently enter the deflection coil because it collides with the acceleration tube wall. Therefore, the mechanical axial alignment adjustment of the electron gun 5 is particularly important. Here, for the mechanical axis alignment of the electron gun 5, the insulating rod 12 passed between the base 4 and the upper support board 8 is used.
a, 12b are driven by motors 13a, 13b to convert the rotation of the insulating rod into a parallel movement or a vertical movement of the arm 9 by a shaft alignment mechanism, for example, a combination of gears or the like.
4X and 14Y are operated, and the electron gun 5 is translated or tilted by the arm 9 to perform axis alignment.

[Problems to be Solved by the Invention] In the device having the above-described configuration, since the insulating rods 12a and 12b are provided between the base 4 and the upper support board 8, both ends of the insulating rod are connected to the ground potential. Wehnelt potential is applied. When a high voltage is supported on both ends of the insulating rod in this way, the potential distribution around it becomes unstable, and discharge (creeping discharge) occurs along the insulating rod, which may damage or contaminate parts inside the device. Is a problem. In addition, such an electric discharge frequently causes a work of cleaning and replacing a damaged part, which causes a problem in observing an electron microscope image.

The present invention has been made in view of the above problems, and an object thereof is to provide a charged particle beam apparatus suitable for use in an electron microscope equipped with a mechanical axis alignment mechanism of an electron gun.

[Means for Solving the Problems] The present invention relates to a multistage accelerating tube in which electrodes for accelerating a charged particle beam are stacked, a charged particle beam source arranged above the accelerating tube, and the multistage accelerating tube. In a charged particle beam device provided with a laminated body in which components for generating or detecting a high voltage are stacked around the laminated body, an elongated hole penetrating the laminated body along the axis of the laminated body is provided. The insulating rod is passed through the elongated hole, the high-voltage side end of the insulating rod is engaged with the alignment mechanism of the charged particle beam source, and the low-voltage side end of the insulating rod is arranged on the low-pressure side for performing the alignment. It is characterized in that the drive mechanism is engaged.

[Operation] According to the present invention, an elongated hole penetrating the laminated body is provided along the axis of the laminated body in which components for generating a high voltage are stacked, and an insulating rod is passed through the elongated hole. The high-pressure side end portion of the insulating rod is engaged with the axis alignment mechanism of the charged particle beam source, and the low-voltage side end portion of the insulating rod is engaged with the drive mechanism arranged on the low pressure side for performing the axis alignment, The drive mechanism aligns the axis of the charged particle beam source.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a device configuration diagram for explaining an embodiment of the present invention. In FIG. 1, the same components as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, 21 is a high voltage detecting voltage dividing column, 22 is a high voltage stability monitoring voltage dividing column, 23 is a dividing resistor,
Reference numeral 24 is a capacitor, 25 is a corona shield, 26 is an insulating tube, and 27 is an elongated through hole.

Each of the high-voltage detection voltage dividing column 21 and the high-voltage stability monitoring voltage dividing column 22 is a column in which a plurality of circuits in which a dividing resistor 23 and a capacitor 24 are connected in parallel are stacked and connected in series via a corona shield 25. Is. A through hole 27 is formed in each of the columns 21 and 22 by a hole provided at the center of the corona shield 25 and an insulating pipe 26 connecting the holes of the stacked corona shields.
The insulating rods 12a and 12b are passed through the penetrating elongated holes 27, and the end portions of the insulating rods on the upper support board 8 side (high-voltage side end portions) are engaged with the axis alignment mechanisms 14X and 14Y of the electron gun 5. The base 4 side (low-pressure side end portion) is engaged with the motors 13a and 13b arranged for axial alignment. Then, the motor is used to drive an axis adjusting mechanism, for example, a mechanism for converting the rotation of the insulating rod into a parallel movement or a vertical movement of the insulating rod by a combination of gears or the like to perform the axis adjustment of the electron gun 5.

In this way, by passing the insulating rod through the partial pressure column,
Since the potential distribution around the insulating rod is stable, the discharge along the insulating rod is less likely to occur.

The above-described embodiment is only one embodiment of the present invention, and the present invention can be modified and implemented.

For example, in the above-described embodiment, the through voltage slot 27 is provided in the high voltage detecting voltage dividing column 21 and the high voltage stability monitoring voltage dividing column 22, and an insulating rod is passed through the hole to engage the electron gun axis alignment mechanism. However, in addition to this, a laminated body in which components for generating a DC high voltage are laminated,
For example, a through hole 27 is also formed in the booster column of the Cockcroft-Walton circuit that combines a capacitor and a diode.
May be provided to pass the insulating rod, and the high-voltage side end portion of the insulating rod may be engaged with the axis alignment mechanism of the electron gun.

[Effects of the Invention] As is apparent from the above description, according to the present invention, an elongated hole penetrating the laminated body along the axis of the laminated body in which components for generating or detecting a high voltage are stacked. Is provided
An insulating rod is passed through the long hole, the high-pressure side end of the insulating rod is engaged with the alignment mechanism of the charged particle beam source, and the low-pressure side end of the insulating rod is moved to the low-pressure side for performing the alignment. By engaging with the driving mechanism arranged, the potential distribution around the insulating rod can be stabilized. Therefore, discharge along the insulating rod is less likely to occur. Further, since the discharge is reduced, the parts in the device are not damaged or contaminated, so that the electron microscope image observation can be smoothly performed.

[Brief description of drawings]

FIG. 1 is a device configuration diagram for explaining an embodiment of the present invention, and FIG. 2 is a diagram for explaining a conventional example. 1: Multi-stage accelerating tube, 4: Base 5: Electron gun, 6: Filament 7: Wehnelt, 8: Upper support board 9: Arm, 10: Bellows 11: Electron gun holding part, 12: Insulating rod 13: Motor, 14: Axis alignment mechanism 15: Dividing resistor, 16: Deflection coil 17: Focusing lens 21: High voltage detecting voltage dividing column 22: High voltage stability monitoring voltage dividing column 23: Dividing resistor, 24: Capacitor 25: Corona shield, 26 : Insulation pipe 27: Through hole

Claims (1)

[Claims] 1. A multistage accelerating tube in which electrodes for accelerating a charged particle beam are stacked, a charged particle beam source arranged above the accelerating tube, and a high voltage generated around the multistage accelerating tube. Alternatively, in a charged particle beam device including a laminated body in which components for detection are stacked, an elongated hole penetrating the laminated body along the axis of the laminated body is provided, and an insulating rod is passed through the elongated hole, The high-voltage side end of the insulating rod is engaged with the axis alignment mechanism of the charged particle beam source, and the low-voltage side end of the insulating rod is engaged with the drive mechanism arranged on the low pressure side for performing the axis alignment. A charged particle beam device characterized by the above.