JP2749355B2 - Electrostatic deflection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Table of Contents] Overview Industrial application Field of the Invention Prior Art Problems to be Solved by the Invention Means for Solving the Problems Action Embodiment One Embodiment of the Present Invention (FIGS. 1 to 5) [Outline] Regarding the electrostatic deflecting device, it is possible to reduce the size of the electrostatic deflecting device while maintaining the physical strength, and to arrange the electrodes with extremely high accuracy, and to beam even if any part is charged up. The object of the present invention is to provide an electrostatic deflecting device capable of preventing the influence from being exerted on the inner peripheral surface of a cylinder made of an insulator and having both ends opened, and a plurality of cylinders extending from the upper end to the lower end of the cylinder. A plurality of electrode pieces are formed at equal intervals integrally with the cylinder by the linear groove of the above, the bottom of the groove or a portion near the bottom is wider than the opening width of the inner peripheral surface of the groove, and The inner peripheral surface of the cylinder and the front A portion of the inner wall surface of the groove that can be seen from the center axis of the cylinder is covered with a metal film, and a portion of the inner wall surface of the groove that is not seen from the center axis of the cylinder due to the electrode piece is an upper end of the cylinder. An insulating region extending from a portion to a lower end and not covered with the metal film is provided.

[Industrial applications]

The present invention relates to an electrostatic deflection device, and more particularly to an electrostatic deflection device for scanning a charged particle beam on a sample.

Deflection is one of the basic technologies in charged particle beam devices. In an exposure apparatus using an electron beam, which is one of charged particles, since low aberration and high speed deflection are required, a deflector is separated into a large deflection and a small deflection.
An electrostatic deflector operating at a low voltage with a high scanning speed is used.

[Conventional technology]

Conventional electrostatic deflecting devices have been used for small deflections and have been placed in the final lens to improve deflection efficiency.
For the same reason, a magnetic field type deflection device for large deflection needs to be arranged in the final lens. Therefore, the magnetic field type deflector and the electrostatic deflector have to be arranged inside the magnetic field type deflector due to the relationship between the deflection efficiency and the size of the device itself. That is, since the electrodes are arranged in the magnetic field, the magnetic field is disturbed. In order to avoid this, when manufacturing multi-pole electrodes, it is common to construct an electrostatic deflection device by forming each electrode with an insulator, covering the surface with a metal thin film and assembling it. It is.

[Problems to be solved by the invention]

However, such a conventional electrostatic deflecting device has a structure in which an electrode is assembled by assembling individual electrodes each having an insulator surface coated with a metal thin film, and thus has the following problems. there were.

That is, since the electrodes are constructed by assembling the individual insulators, there is a limit in the electrode mounting accuracy, and when the size of the electrodes is constant, if the number of poles of the electrodes increases, the distance between the facing electrodes cannot be increased. Not get. Therefore, it is necessary to apply a higher voltage to obtain the same deflection amount,
Not only does a large power supply become necessary, but it also causes a reduction in scanning speed. In addition, as the size of the electrostatic deflecting device increases, the size of the electromagnetic coil constituting the magnetic field type deflecting device outside the electrostatic deflecting device also increases, and the scanning speed is further reduced due to the increase in the inductance of the coil. Furthermore, even if the working accuracy of the individual electrodes is high, there is a problem that the electrostatic deflection device itself is very small, so that it takes a lot of time to assemble, and that the assembling accuracy cannot be improved.

In addition, there is one in which a support and all multipolar electrode pieces are integrally formed. However, since this structure has a structure in which the support and the one end of the electrode are integrated at a certain point, if the electrode is long, the strength is insufficient. Must be insulated from
Exposure of the insulating portion to charged particles impinging on the insulating portion causes a charge-up that generates an indeterminate potential. The potential due to the charge-up causes the charged particles to deflect irregularly, resulting in a decrease in accuracy. In order to avoid this, a cylinder connected to the ground is arranged further inside the support portion so that the charged particles do not hit the exposed insulating portion, thereby canceling the effect of charge-up of the insulating portion on the beam. Therefore, since the cylinder connected to the ground is provided inside the support, the electrostatic deflecting device must be large, leading to a reduction in the scanning speed as described above.

Therefore, the present invention can reduce the size of the electrostatic deflecting device while maintaining the physical strength, and arrange the electrodes with extremely high accuracy, and even if any part is charged up, the beam is not affected. It is an object of the present invention to provide an electrostatic deflecting device that can be configured as follows.

[Means for solving the problem]

The electrostatic deflecting device according to the present invention achieves the above object,
A plurality of electrode pieces are formed at equal intervals integrally with the cylinder by means of a plurality of linear grooves extending from the upper end to the lower end of the cylinder on the inner peripheral surface of the cylinder having both ends open and formed of an insulator. The bottom or a portion close to the bottom is wider than the opening width of the groove on the inner peripheral surface, and the part of the inner peripheral surface of the cylinder and the inner wall surface of the groove that can be seen from the central axis of the cylinder is made of metal. While being covered with a film, an insulating region that is not covered with the metal film from the upper end to the lower end of the cylinder is provided in a portion of the inner wall surface of the groove that cannot be seen from the center axis of the cylinder by the electrode pieces. It is characterized by the following.

[Action]

In the present invention, the metal film formed on the portion that can be seen from the beam axis is divided by the insulating region of the unseen portion,
As a result, many electrode pieces are formed.

Therefore, an electrically insulated electrode piece is formed,
Since the electrode pieces are integrally formed with the cylinder as the support, sufficient strength and sufficient processing / assembly accuracy can be obtained even if the individual electrode pieces are miniaturized. In addition, since all portions visible from the charged particle beam are covered with the metal film, the influence of charge-up caused by the exposed insulator portion hitting the beam is appropriately avoided.

〔Example〕

 Hereinafter, the present invention will be described with reference to the drawings.

Principle explanation The present invention provides an equal number of grooves on the inner surface of a cylinder made of an insulator along the traveling direction of the charged particle beam to the electrodes, and coats the inner surface of the cylinder with a metal film to insulate a predetermined area of the groove. By providing a body and electrically insulating, a plurality of electrodes are formed on the inner surface of the cylinder. The groove is defined in a shape having an area such that the insulating portion is not exposed to irradiation of the charged particle beam in the radiation direction.

Therefore, a plurality of electrode pieces are integrally formed on the inner surface of the cylinder, so that each electrode piece can be downsized. In addition, the electrode piece can be downsized by integrating the support and the electrode piece. However, sufficient strength can be ensured.

Embodiment An embodiment will be described below based on the above basic principle. FIGS. 1 to 5 show an embodiment of the electrostatic deflection apparatus according to the present invention. This embodiment is an example applied to an electrostatic deflection apparatus having eight electrodes. FIG. 1 is a perspective view of the electrostatic deflecting device, FIG. 2 is a sectional view taken along the line II in FIG. 1, and FIG.
FIG. 2 is a sectional view taken along the line II-II in FIG.

First, the configuration will be described. 1 to 3, reference numeral 1 denotes an electrostatic deflecting device, and reference numeral 2 denotes a cylinder made of an insulator. The cylinder (cylinder) 2 has T in the radial direction (ie, the radiation direction of the charged particle beam) from the inner surface 2a of the cylinder 2 to the outer surface 2b.
Eight shaped deformation grooves (grooves) 3 to 10 are defined, and the deformation grooves 3 to 10 are formed.
By defining 10, eight electrode pieces 11 to 18 are formed. Deformation grooves 3 to 10 are grooves in the area where the charged particle beam is received
3a to 10a and grooves 3b to 10b located outside the beam receiving area, that is, grooves 3b to 10b located in the area not receiving the beam. The deformed grooves 3 to 10 can be formed by using, for example, a wire cutter, but may be a mode in which an insulator is injected into a mold in which an electrode and a support are formed in advance and molded.

The shape of the deformed grooves 3 to 10 is not limited to the T-shape as in the present embodiment, but may be any as long as it has an area which does not receive the radiation of the charged particle beam. Shapes as shown in (a) to (g) may be used.

That is, the T-shaped deformed groove 20 shown in FIG.
Is composed of a groove 20a in an area for receiving the charged particle beam and a groove 20b outside the area for receiving the beam. Also,
The circular deformed groove 21 shown in FIG. 5B is composed of a groove 21a in an area for receiving the charged particle beam and a groove 21b outside the area for receiving the beam. The L-shaped deformed groove 22 shown in FIG. 4C is composed of a groove 22a in an area for receiving the charged particle beam and a groove 22b outside the area for receiving the beam. The L-shaped deformed groove 23 shown in FIG. 4D is composed of a groove 23a in an area for receiving the charged particle beam and a groove 23b outside the area for receiving the beam. Further, the circular deformed groove 24 shown in FIG. 3E is composed of a groove 24a in an area for receiving the charged particle beam and a groove 24b outside the area for receiving the beam. Further, the L-shaped deformed groove 25 shown in FIG. 6F is composed of a groove 25a in an area for receiving the charged particle beam and a groove 25b outside the area for receiving the beam. Also, the triangular deformed groove 26 shown in FIG. 9G has a groove 23a in an area for receiving the charged particle beam,
And a groove 26b outside the area for receiving the beam.

It goes without saying that the number of the deformation grooves 3 to 10 is not limited to eight as long as it corresponds to the number of electrodes to be formed. Further, electrode pieces 11 to 18 located between two adjacent deformed grooves 3 to 10 are shown in FIG. 5 as another embodiment. The electrode piece 31 shown in FIGS. 5 (a) to (d)
To 34 are bases 31a to 34a, and tips 31b to 34b formed integrally with the bases 31a to 34a and having a larger cross-sectional area than the base,
Consists of The tip 31b of the electrode piece 31 in FIG. 5 (a) has a flat inner surface, and the tip 32b of the electrode piece 32 in FIG. 5 (b) has an arc-shaped concave inner surface. In FIG. 5 (d), the tip 33b of the electrode piece 33 has a semicircular convex inner surface, and the tip 34b of the electrode piece 34 in FIG. 5 (d) has a triangular convex inner surface.

The inner surface 2a of the cylinder 2 is entirely covered with a metal film by, for example, metal plating, except for a part of the grooves 3b to 10b of the deformed grooves 3 to 10. The individual electrode pieces 11 to 18 are electrically separated by portions not covered with the metal film, that is, strip-shaped insulating regions (insulating portions) 3c to 10c where the insulator is exposed. This band-shaped insulating region is formed by coating the entire inner surface of the cylinder with a metal film and then peeling it off with a wire cutter or peeling it off by electric discharge machining. Band-shaped insulating region 3c ~
10c may be formed at any position of the grooves 3b to 10b of the deformed grooves 3 to 10 as long as it is not visible from the charged particle beam extending in the radiation direction. For example, the position (a) shown in FIG. ) May be formed at any position. Therefore, the inner surfaces 2a of the opposing electrode pieces 3 to 10 form a pair of electrodes 11a to 18a. And the electrode 11
Since a to 18a have a structure integrally formed with the cylinder 2 as a support member, they have high physical strength and are miniaturized. Further, by forming the strip-shaped insulating regions 3c to 10c at positions that are not visible from the charged particle beam, the individual electrode pieces 11 to 18 are electrically separated, while all the portions visible from the charged particle beam are conductors. Since the metal film is covered, the exposed insulating portion as in the conventional example can be eliminated to avoid the influence of the charge-up.

As shown in FIG. 1, the ends of the electrode pieces 11 to 18 are made to protrude beyond the end of the cylinder 2 and the band-shaped insulating regions 3c to 10c
Are extended in the radial direction on the end face of the cylinder 2 so as to be invisible from the charged particle beam, thereby forming a contact point 35 for applying a predetermined voltage to the electrodes 11a to 18a (FIG. 1 shows an electrode). Only the contact 35 of 18a is shown). Further, as a modification of the end portion of the strip-shaped insulating region, a shape like the strip-shaped insulating region 36 may be used. In FIG. 1, the band-shaped insulating regions 9c, 10c and 36 are indicated by thick lines. Further, in this embodiment, since all the deformed grooves 3 to 10 are electrically connected by the metal film, they may be dropped to the ground at one place (for example, (c) in FIG. 2).

As described above, according to the present embodiment, by forming a plurality of electrode pieces 11 to 18 on the inner surface 2a of the cylinder 2, the individual electrode pieces 11 to 18 can be reduced in size, and By integrating the cylinder 2 and the electrode pieces 11 to 18 as described above, sufficient strength can be ensured even if the electrode pieces 11 to 18 are downsized. Also, the ends of the electrode pieces 11 to 18 are made to protrude from the two ends of the cylinder as the support. Therefore, even at the ends of the electrode pieces 11 to 18, the insulator exposed portions 3c to 10c and 36 of the support are not visible from the beam, so that any part of the electrostatic deflection device 1 does not affect the beam due to charge-up. Can be

Furthermore, when injecting and molding an insulator of a mold in which a plurality of electrodes and a support are formed in advance, the accuracy between the electrodes is determined by the mold, and the inner surface of the cylinder or polygonal cylinder is deformed using a wire cutter. When the grooves 3 to 10 or 20 to 26 are formed, since the mutual accuracy between the electrodes 11a to 18a is determined by the machining accuracy of the mold, the accuracy is not related to the assembly accuracy of the electrodes 11a to 18a. It is possible to easily obtain an electrostatic deflecting device.

〔The invention's effect〕

According to the present invention, it is possible to reduce the size while maintaining the physical strength, and to arrange the electrodes with extremely high accuracy, so that even if any part of the electrode is charged up, the beam is not affected. Can be.

[Brief description of the drawings]

1 to 5 are views showing an embodiment of the electrostatic deflecting device according to the present invention, FIG. 1 is a perspective view thereof, FIG. 2 is a sectional view taken along arrows I to I in FIG. The figure is a cross-sectional view taken along the arrows II to II in FIG. 1, FIG. 4 is a cutaway plan view showing a deformed groove of another embodiment, and FIG. 5 is a cutaway plan view showing an electrode piece of another embodiment. 1 ... electrostatic deflector (electrostatic deflector), 2 ... cylinder (tube), 2a ... inner surface, 2b ... outer surface, 3-10, 20-26 ...
Deformation grooves (grooves), 3a to 10a, 20a to 26a ... groove portions in the beam receiving area, 3b to 10b, 20b to 26b ... groove portions outside the beam receiving area, 3c to 10c, 36 ... band-shaped insulating region ( Insulating parts), 11-18, 31-34 ... electrode pieces, 11a-18a ... electrodes,
31a to 34a: base portion, 31b to 34b, distal end portion, 35a: contact point.

Claims (1)

(57) [Claims] 1. A plurality of electrode pieces are integrally formed with an inner peripheral surface of a cylinder made of an insulator by a plurality of linear grooves extending from an upper end portion to a lower end portion of the cylinder, both ends being open. The bottom of the groove or a portion close to the bottom is wider than the opening width in the inner peripheral surface of the groove, and a portion of the inner peripheral surface of the cylinder and the inner wall surface of the groove that can be seen from the central axis of the cylinder. While covering with a metal film, of the inner wall surface of the groove, in the portion that can not be seen from the center axis of the cylinder by the electrode piece, the insulating region that is not covered with the metal film from the upper end to the lower end of the cylinder An electrostatic deflecting device characterized by being provided.