JPH0532927Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a charged particle beam device, and more specifically, a charged particle beam device that prevents the charged beam from shifting from the optical axis and makes it possible to perform focus correction at high speed. Regarding line equipment.

[Prior art] In conventional electron beam exposure equipment, etc., the second
As shown in the figure, an electron beam 2 from an electron gun 1 is focused by a focusing lens 3 and an objective lens 4, and is irradiated onto a sample 5 in an image manner. Focus correction is performed by supplying a correction signal (excitation current) for focus correction to the coil 6.

Further, as shown in FIG. 3, a correction electrode 7 for focus correction is arranged within the magnetic field formed by the objective lens 4,
Focus correction is performed by supplying a correction signal (voltage) to the correction electrode 7 from a correction power source 8 and changing the electric field strength formed by the correction electrode 7.

[Problems to be Solved by the Invention] In the conventional device described above, for example, in the former focus correction coil 6, when a correction signal is supplied to the focus correction coil 6, the focus correction coil 6 The focal point cannot be moved a predetermined distance at high speed due to the delay in magnetic field change due to the inductance, and therefore, the focus cannot be corrected at high speed. Furthermore, it is extremely difficult to completely align the mechanical axes of the objective lens 4 and the focus correction coil 6 due to processing precision, assembly precision, and the like. Therefore, when a correction signal is supplied to the focus correction coil 6 to operate it, the lens axis of the objective lens 4 and the correction axis of the focus correction coil 6 do not necessarily match, and the electron beam 2 deviates from the optical axis Z. It ends up. In addition, in the latter focus correction using the correction electrode 7, the delay in focus correction due to the delay in magnetic field change does not pose much of a problem as in the former focus correction using the focus correction coil 6, but the lens axis of the objective lens 4 and the correction electrode It is difficult to match the correction axes of the electrodes 7 and 7, and therefore, the latter correction electrode 7 also has the disadvantage that the electron beam 2 is deviated from the optical axis Z.

The present invention has been developed in view of the above points, and an object of the present invention is to provide an apparatus that can prevent an electron beam from being deviated from the optical axis due to focus correction and can perform focus correction at high speed.

[Means for solving the problem] The present invention for achieving the present purpose is to electrically insulate the pole piece of a magnetic field type lens for focusing a charged particle beam from a column constituting a charged particle beam device. The pole piece is characterized in that it is configured to apply a focus correction potential to the pole piece.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In FIG. 1, the same components as those of the conventional device shown in FIG. 2 are given the same numbers and their explanations will be omitted. 1st
In the apparatus shown in the figure, a pole piece 4a constituting an objective lens 4 is electrically insulated from a column 9 such as a mirror body by an insulating member 10, and a correction voltage is applied to the pole piece 4a by a correction power source 8. It is configured so that it can be applied at a certain angle.

By the way, in a weakly excitation lens, if the focal length is f, the acceleration voltage is V, and the voltage applied to the lens is V, it is expressed as f∝(-V).

Therefore, by changing the voltage V applied to the pole piece 4a by the correction power source 8 and changing the electric field strength formed by the pole piece 4a, the focal length f of the electron beam 2 can be changed. Focus correction can be performed. Further, in such a device, there is no delay in magnetic field change due to inductance as in conventional devices, so focus correction can be performed at high speed. Further, since the pole piece 4a also serves as a correction electrode, the lens axis of the objective lens 4 and the correction axis by the pole piece 4a can be perfectly aligned, so that the electron beam 2 will not deviate from the optical axis Z.

[Effects of the Invention] As described in detail above, the present invention provides a charged particle beam device that can prevent the charged particle beam from being deviated from the optical axis and perform focus correction at high speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the configuration of an embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining a conventional device. 1... Electron gun, 2... Electron beam, 3... Focusing lens, 4... Objective lens, 5... Sample, 8...
Correction power supply, 9...column, 10...insulating member.

Claims (1)

[Scope of utility model registration request] A pole piece of a magnetic field type lens for focusing a charged particle beam is electrically insulated from a column constituting a charged particle beam device, and a potential for focus correction is applied to the pole piece. Charged particle beam device.