JPS59180943A - Electrostatic deflector for charged particle beam - Google Patents

Abstract

PURPOSE:To provide an electrostatic deflector for a charged particle beam which will produce small deflection distortion and astigmatism even at a large- angled deflection, by making the deflector to be of such structure that circular electrodes are embedded in an insulating case. CONSTITUTION:Eight electrodes 12 are embedded in the insulating material of an insulating case 11 disposed in an axial symmetrical manner. The portions of the eight electrodes 12 to be fixed to the insulating case 11 and the electrodes themselves are made circular, and the circular hole 13 in the center of the case 11 for the ion beam to pass through is made to have a slightly larger diameter than the envelope line formed by the circles of the eight electrodes 12. The joint portions of the insulating case 11 with the electrodes 12 are made circular for ease of working and for achieving high working accuracy, and thus the electrodes can be embedded in the holes with high accuracy and no play. As the circular hole 13 in the insulating case 11 has eight cuts at the positions where the electrodes are inserted, the eight portions of the electrodes peeping out from the cut portions act as eight deflecting electrodes. In this way, the electrostatic deflector for a charged particle beam producing small deflection distortion and astigmatism can be provided.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to an electrostatic deflector used for charged particle beams, and in particular to a deflection electrode configuration suitable for minimizing deflection distortion and deflection astigmatism aberrations. The present invention relates to an electrostatic deflector for charged particle beams comprising:

[Background of the invention]

Electrostatic deflectors have larger aberrations than magnetic field deflectors, so
Generally, a magnetic field type is used, or an electrostatic type is used only for small angle deflection.

On the other hand, with the recent development of high-intensity ion sources, the application of micro-ion beams to semiconductors has come to be considered, and large-angle deflection has become necessary.

Conventionally, as shown in Fig. 1 (the upper figure is a plan view and the lower figure is a cross-sectional view), each electrode 2, which is plate-shaped and has a protrusion on the mounting part 1, is attached to an insulating case 3 by a screw 4. It was installed with etc. In other words, the structure was such that a part of the electrode was attached to the insulating case while being in contact with the insulating case. For this reason, (1) the geometrical parallelism and symmetry of the electrode plate with respect to the charged particle beam are insufficient; and (2) the accuracy of the circumferential positioning of the electrode plate (radial position accuracy) is poor.

(3) There were drawbacks such as individual differences in electrode attachment, making it difficult to produce products of consistent quality.

Conventionally, this was used for small-angle deflection, so anything could be used, but if this was used as is for large-angle deflection, it would have drawbacks such as increased deflection distortion and deflection astigmatism.

[Purpose of the invention]

An object of the present invention is to eliminate such drawbacks and provide an electrostatic deflector for charged particle beams that exhibits small deflection distortion and small deflection astigmatism even during large-angle deflection.

[Summary of the invention]

Therefore, in the present invention, the method of attaching the electrode to the insulating case is changed in order to improve accuracy, and a circular or rectangular electrode is embedded in the insulating case.

This means that electrodes that have been mechanically machined with high precision are mechanically fitted, and it depends only on the processing precision of the machine tool and the fitting clearance. By making an insulating case, the accuracy can be increased as much as possible.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 2 (the upper figure is a plan view and the lower figure is a cross-sectional view), the electrostatic deflector of the present invention has eight electrodes 12 arranged axially symmetrically through an insulator of an insulating case 11. The fixed part of the eight electrodes 12 to the insulating case 11 and the electrodes themselves have a golden circular shape, and the circular hole 13 in the center of the case through which the ion beam passes is defined by the envelope of the circle of the eight electrodes. The diameter was also made slightly larger. The connection part between the insulating case and each electrode is circular, which is easy to process and easy to maintain accuracy.
The structure is such that the electrode is inserted into the precisely machined electrode insertion hole of the insulating case (drive-in) without any gaps.

Therefore, eight notches are formed in the center round hole of the insulating case at the electrode rod. The electrode portions exposed from the notch function as eight deflection electrodes.

In addition, the number of electricity/sample is not limited to the above eight,
Generally, it can be applied to 4N (N22) pieces required for static four-way deflection.

In this embodiment, the method of fixing the insulating case and the electrode is by implantation, but depending on the case, it is also possible to use an adhesive in combination.

If the deflection accuracy is high and it is inappropriate for the insulator of the insulating case to be visible from the charged particle beam side, it is necessary to move it closer to the center as shown in Figure 3 (the upper figure is a plan view and the lower figure is a cross-sectional view). In addition, a protrusion 22 that hides the insulating case 24 is provided on a part of the electrode 21.
This can be done by adding . The angle measurement in this case can be determined by a pin 23 driven into the electrode 21 in a direction perpendicular to the axial direction. Furthermore, it is of course possible to use an electrode 31 having a rectangular embedded part as shown in FIG. 4 (the upper figure is a plan view and the lower figure is a cross-sectional view) without using these bottles 23. be.

In the figure, 32 indicates an insulating case.

〔Effect of the invention〕

By applying the present invention, the following advantages were obtained.

The connection part between the insulation case and each electrode? The shape is originally circular, which is easy to process and improves machining accuracy, and the sheath is inserted into the well-processed electrode insertion hole of the insulating case without any gaps (driving), so the electrode placement can be done with the precision of the hole in the insulating case. This electrostatic deflector now has the following advantages.

(1) The accuracy of dividing the electrode in the circumferential direction has been improved.

(2) The parallelism and symmetry of the counter electrode in the axial direction (ion beam passing direction) were improved.

(3) There is no need to adjust the electrodes when attaching them to the insulating case, reducing variations in quality when making a large number of electrodes. It also reduced work time.

As a result, the deflection distortion and astigmatism of conventional deflectors can be reduced to about 10%, making it possible to realize an extremely high-performance deflector. For example, when this deflector is applied to a drawing device that forms a desired fine pattern on a υ sample using a charged particle beam such as an ion beam,
3 In the ion optical system for crA deflection, 0.1 μm
It is now possible to form patterns with different line widths.

It is obvious that the present invention can be applied to stigmas, aligners, etc. by changing the number of electrodes.

[Brief explanation of drawings]

Figure 1 shows a plan view and a front view of a conventional deflector (
sectional view). FIG. 2 is a plan view and a front view (sectional view) showing an embodiment of the deflector of the present invention. Figure 3 shows
A plan view and a front view (sectional view) showing other embodiments of the present invention
It is. FIG. 4 is a plan view and a front view (sectional view) showing still another embodiment of the present invention.

Claims (1)

[Claims] 1. In an electrostatic deflector in which electrodes of 41 mm or more are arranged axially symmetrically with an insulator in between, a notch having the same shape as a part of the electrode shape is provided in the insulator, and the electrode is placed in that part. An electrostatic deflector for charged particle beams, characterized in that a charged particle beam is inserted therein.