JPS61214341A - Charged beam focusing device - Google Patents

Abstract

PURPOSE:To simplify the structure of a charged beam focusing device by focusing the charged beam by complete charging of an insulating member which has a hole for passing the beam and is located in the path of the beam. CONSTITUTION:A charged beam focusing device for lithography or a similar method is assembled by locating an insulating member 7, which has a central hole extending along the beam axis, in the path of a charged beam 1 and fixing the flange 7a of the insulating member 7 to the outer wall 4 of a vacuum device by means of an adhesive or similar material. A blocking electric field 8 produced by completely charging the insulating member 7 is used to focus the beam 1 toward the center of the member 7 thereby producing a charged beam 1c with high density. The beam 1 can be focused into an arbitrary shape by properly selecting the shape of the cross section of the hole of the member 7. Accordingly, it is possible to produce a charged beam focusing device with simple structure which is free from any trouble such as discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention is applicable to physical analysis apparatuses that have recently been used in phosphorography and sputtering, which are the basic steps of semiconductor device manufacturing, or as a means of evaluating practical materials. The present invention relates to a focusing device for ion/electron beams (hereinafter collectively referred to as charged beams), which occupies a position as an important component.

[Summary of the Invention] The present invention relates to a focusing device for charged beams (ion/electron beams) used in phosphorography, sputtering, etc., by utilizing the charge-up phenomenon of an insulating material for focusing the charged beam. With a simple component configuration, it is possible to obtain a specified beam shape without the need for a high-voltage power supply and without causing problems such as wood discharge.

[Prior Art] With the trend toward higher density of semiconductor devices and higher purity of manufacturing materials, it is also used as a probe for inducing reactions such as beam exposure and etching, as well as for high-resolution SIMS, SEM,
In recent years, there has been an increasing demand for increasing the radio wave density of a charged beam into a desired shape even as a probe for physical analysis such as an Auger-SEX device.

In order to realize this request, the charged beam focusing devices that have been tried so far can be roughly divided into (a) multiple metal electrodes placed in the path of the charged beam, and voltage applied to these electrodes independently; They can be classified into two types: (b) electrostatic lens type, which creates a focused electric field by applying an electric field, and (b) magnetic lens type, which utilizes the focusing effect of a magnetic field by placing an electromagnet around the orbit of the charged beam.

[Problems to be Solved by the Invention] However, the above-mentioned conventional devices each have the following drawbacks.

In the electrostatic lens type (a), as shown in FIG. 1, there is a charged beam 1, an electrostatic lens 2, an electrode holding part (usually an insulating material), 3. The conventional electrostatic lens type device, which is composed of an outer wall 4 of the vacuum device, a voltage introduction terminal 5, and a high voltage power source 6, requires a Therefore, multiple electrodes are required, and all of the electrodes 2 must be electrically held independently by the electrode holding part 3. Therefore, considering the insulation, etc., the structure becomes complicated, and the lens The disadvantage is that a high-voltage power supply is required for each electrode.(However, if some of the electrodes are at ground potential,
A method of reducing the number of required power supplies is also commonly used.

) In recent years, large-scale charged beam devices that have been widely used have adopted a focusing system using multiple combined lenses, and at the same time, the accelerating voltage of the charged beam has become higher and higher. It is thought that considering the structure and retention method of this will become an increasingly difficult problem in the future.

In the magnetic field lens type shown in (b), the electromagnets are arranged around the charge and beam orbits, so the lens mechanism becomes too large-scale and has the disadvantage that it is difficult to use in a simple charged beam device. In addition, since the magnetic field acts in proportion to the reciprocal of the mass of the charged particle, there is a problem in that it has a small focusing effect on ions and is difficult to utilize. Furthermore (a),
(b) Electrostatic layer.

With either magnetic field type lens, it is considered extremely difficult to focus the charged beam into the expected shape, considering the shape of the required deflection plate electrode or magnet.

Therefore, the purpose of the present invention is to take advantage of the advantages of the electrostatic lens type. The component configuration allows focusing to be performed without the need for a high-voltage power source.

We aim to significantly improve the function of a charged beam concentrator by adding (3) the absence of problems such as discharge due to the nature of the wood, and (4) the ability to focus a charged beam into the expected beam shape. It is something to do.

[Means for Solving the Problems] The present invention is characterized in that an insulating material having holes through which the charged beam passes is disposed in the path of the charged beam.

Further, in the present invention, the hole has a cross section corresponding to a specified beam focusing shape, and the charged beam passes through the hole by utilizing the charge-up effect of the insulating material accompanying the irradiation of the charged beam. It is characterized by increasing the spatial density with a specified beam focusing shape.

[Function] Since the present invention uses a charged beam concentrator made of an insulating material, the charge-up phenomenon of the insulating material provides a focusing effect on the charged beam, thereby preventing problems such as discharge. This provides advantages such as a simpler structure.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

The present invention has an essential feature in that the charge-up phenomenon of an insulating material is utilized for the focusing action of a charged beam. An example of the arrangement and configuration of the charged beam focuser of the present invention is shown in FIG. 2(A). FIG. 2(B) schematically shows the focusing action of the present focusing device. In FIG. 2, 7 is a cylinder (insulator concentrator) made of an insulating material, and has a horizontal circular flange (flange) 7a at its upstream end. Further, the flange 7a is fixed to the outer wall 4 of the vacuum apparatus by adhesive or the like. When the charged beam 1 hits this cylinder 7, the insulating material of the cylinder 7 is charged up, as shown in Fig. 2 (B).
A blocking electric field against the charged beam as shown by the broken line 8 is created. This blocking electric field 8 is.

A part of the charged beam 1 that originally hit the flange 7a of the cylinder 7 is bent toward the inside of the cylinder.The charged beam lb is bent into the inside of the cylinder 7 and the charged beam 1a that originally passed through the inside of the cylinder. is focused at the center of one cylinder 7 due to the charge-up effect generated in the inner cylindrical portion 7b of the cylinder 7, so that a charged beam lc with a high spatial density is obtained.

This focusing device of the present invention utilizes the charge-up phenomenon created by the incident charged beam l due to an insulating material.
There is no need for a voltage introduction terminal into the vacuum or a high-voltage power supply, which were required with the conventional electrostatic lens type, making the configuration extremely simple.

Moreover, since the charge-up potential is automatically determined to a constant value in accordance with the acceleration energy of the incident charged beam 1,
It is possible to design a concentrator with a desired focusing effect at any charged beam acceleration voltage. In addition, the concentrator 7
Since it is possible to connect directly to the wall 4 of the vacuum container, there is an advantage that the means for holding the concentrator is simple and troubles such as discharge do not occur.

When we actually investigated the focusing effect on the ion beam using an insulator 7 having a cylindrical shape with flanges (hereinafter referred to as a focuser), we found that the beam diameter was approximately 5+++s (current density) in front (upstream) of this focuser 7. An ion beam 1 of 50 k A/c+a2) is passed through an insulator focuser 7 having an inner cylindrical diameter of about 4.2 mm, and the beam diameter is about 2+++ m (current density is about 300 g) behind (downstream of) the focuser 7. A/
cm2).

In the above embodiment, the charged beam focuser 7 having a cylindrical hole was used as an example, but if the blocking electric field of the charged beam caused by charge-up is largely dependent on the shape of the insulating material focuser, the focusing can be improved. It is also possible to create charged beams with various desired characteristics by changing the shape of the device.
The hole 7e is surrounded by a curve such as a circle, an ellipse, a hyperbola, or a parabola, and the hole 7e is surrounded by a triangle, rectangle, polygon, etc. as shown in FIGS. It is possible to obtain a beam shape corresponding to the shape of the hole by modifying the shape of the hole. In addition, the shape of the end surface 7a of the insulator concentrator 7, which is irradiated with the charged beam 1, is also important in obtaining the desired beam characteristics, and the shape of the end surface and the hole may be combined with the various shapes listed above. One possible example is a case where four regular-shaped holes are formed in an insulator with a circular end face shape.

(2) As shown in FIG. 3(I), it is also possible to make the cylindrical portion of the insulator concentrator 7 long and use it as a drift tube.

■ As shown in Figures 3 (J) to (L), both ends or a part of the cylindrical part of the insulator concentrator 7, or the central part are constricted, widened, or stepped to diverge the incident charged beam. It is also possible to provide a focusing effect corresponding to the angle, or to obtain a desired beam divergence characteristic.

■ As shown in FIGS. 3(M) and (N), when the insulator concentrator 7 has a flange at both ends or a part thereof, the flange part is made into a dish shape or has a curvature.
It is also possible to further increase the focusing effect.

(2) It is also possible to obtain desired beam characteristics by combining the structures (1) to (2) above.

In realizing the configuration examples of the hole type concentrator mentioned above,
Insulating materials generally have difficulties in terms of workability, but in that case, for example, as shown in FIG. Alternatively, as shown in FIG. 3(B), an insulating material is coated on the metal 12 processed into a desired shape and then sintered,
This can be solved by depositing the insulating material 11 using a manufacturing method such as chemical vapor deposition (CVO; vapor phase growth accompanied by a chemical reaction), plasma CVO, or sputter deposition (sputtering).

The insulator 11 made on metal by such a manufacturing method also
It can be expected that the charged beam will be focused according to the principles of the present invention. Conversely, as shown in Figure 4(C),
A part of the insulating material 11 (for example, the inside of an insulating cylinder)
Depositing a conductive material 14 to induce a charge-up phenomenon of a spatially uniform potential is also a modification to enhance the function of the concentrator of the present invention in some cases. It should be noted that if such a conductive material component or metal part has an external connection terminal 14, it would be useful to refresh the charge-up and quickly realize the optimum conditions for another acceleration voltage. Furthermore, it is also effective to create the concentrator of the present invention by combining several types of insulators 11G and 110, as shown in FIG. 4(D).

[Effects of the Invention] As explained above, according to the present invention, since the charge-up phenomenon of an insulating material is utilized for the focusing action of a charged beam, the intended purpose is achieved and the lens structure and holding method are improved. It is expected that the method will be much simpler and will greatly contribute to simplifying the manufacturing process and reducing manufacturing costs of charged beam devices.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the arrangement of a conventional electrostatic lens type charged beam focusing device; FIG. 2(A) is a sectional view showing an example of the arrangement of the charged beam focusing device of the present invention; FIG. ) is a mode diagram showing the principle of operation, and Fig. 3 (A
) to (N) each show an example of the processed shape of the hole in the concentrator of the present invention, and (A) to (H) are front views of the hole, and ( I) to (N) are sectional views of the cylindrical portion, and FIGS. 4(A) to 4(D) are sectional views each showing an example of the method of manufacturing the concentrator of the present invention. DESCRIPTION OF SYMBOLS 1... Charged beam, 2... Electrostatic lens electrode, 3... Electrode holding part, 4... Outer wall of vacuum device, 5... Voltage introduction terminal, B... High voltage power supply. 7... Concentrator made of insulator, 8... Blocking potential (blocking electric field) accompanying charge-up. 11, IIA, IIB, tiG, 110... insulator,
12.13...Metal, 14...External connection terminal. Figure 1 Figure 2 '15 8 Wind and electric field Figure 3

Claims (1)

[Claims] 1) A charged beam concentrator characterized in that an insulating object having a hole in the center that penetrates in the same direction as the beam is disposed in the path of the charged beam. 2) The hole has a cross-sectional shape corresponding to an expected beam shape, and the charged beam is shaped into the expected beam shape through the hole, according to claim 1. charged beam focuser. 3) A claim characterized in that the spatial density of the charged beam passing through the hole is increased by the cross-sectional shape of the hole by utilizing a charge-up phenomenon of the insulating object due to irradiation with the charged beam. Charged beam focuser according to item 2. 4) The charged beam concentrator according to any one of claims 1 to 3, wherein the insulating object is a thin disk having a small hole in the center.