JPH06223762A - Device for accelerating charged particle - Google Patents

Abstract

PURPOSE:To avoid the influence of metallic particles on an ion implanted substrate, which is caused by the shock of charged particles colliding with the wall surface of a passage for charged beams by making the inner circumferential wall of the passage through which the ion beams pass, divergent forward in cross section. CONSTITUTION:In order that charged particle beams 3 extracted out of an ion source 2 are shocked onto an objective substrate 4 in which ions are implanted, with specified energy, the mass of ions 3 is measured by an analyzer magnet 6 in an analyzer chamber 5 so as to allow the ions 3 to be introduced into an acceleration pipe 7. The ions 3 are then accelerated so as to be shocked against the substrate 4, and they are also horizontally and vertically scanned. The inner circumferential wall of a passage 13 for the ions 3 is made divergent forward in cross section. By this constitution, the contamination of the substrate 4 can be avoided, which is caused by metallic particles produced by the shock of the charged beams against the inner circumferential wall of the passage 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle accelerator suitable for application to, for example, an ion implantation apparatus.

[0002]

2. Description of the Related Art The general construction of a charged particle accelerator, for example, an ion implantation apparatus, is shown in FIG.
In order to bombard the ion beam extracted from the ion source 2, that is, the charged particle beam 3 onto the ion-implanted substrate 4 on which the target ion implantation is performed with required energy, the vacuum container 1 is configured to In the analyzer chamber 5, only the required ion species are subjected to mass analysis in the analyzer chamber 5 and introduced into the accelerating tube 7 to accelerate the ions, and the ions are horizontally moved by the first and second deflecting means 8 and 9. In addition, vertical deflection is performed to bombard the target substrate 4 with the ion beam with required energy, and horizontal and vertical scanning is performed.

In the figure, 10 is a diffusion pump of an ion source, 11 is a diffusion pump of a beam line and an end station, and 12 is a Faraday cage.

In such an ion implantation apparatus, the ion beam (charged electron beam) passage 13 of the vacuum container 1 is provided.
So-called ion line, analyzer chamber 5
Is made of metal, generally SUS (Fe-Cr-Ni alloy).

However, in actuality, the ion beam is directed toward the substrate 4 while being spread by the repulsive force of the ions, so that the ions impact the inner peripheral wall surface of the passage 13 and the wall surface of the constituent metal Generate particles.

The impact of the ions on the inner peripheral wall of the passage 13 is remarkably generated at the bent portion 14 of the passage 13 as seen on the rear side of the deflecting means 9 shown in FIG.

When the metal particles thus generated are directed to the substrate 4, the substrate 4, for example, when it is a semiconductor substrate, is contaminated with metal and is formed on the semiconductor substrate. This causes deterioration of characteristics of various semiconductor elements, nonuniformity of characteristics, deterioration of reliability, and the like.

[0008]

SUMMARY OF THE INVENTION The present invention provides a charged particle accelerating device which can surely perform ion implantation into various substrates such as semiconductor substrates without generating metal contaminant particles or the like.

[0009]

In the present invention, as shown in the schematic configuration of one example in FIG. 1, an inner peripheral wall of a passage 13 through which charged particles in a vacuum container 1 pass is shown in FIGS. As shown in the figure, the cross-sectional shape widens toward the front.

In the present invention, the inner peripheral wall of the passage 13 is formed as shown in FIG.
As shown in, the cross-section quadratic curve expanding toward the front has, for example, a parabolic or hyperbolic shape.

Further, according to the present invention, the inner peripheral wall of the passage 13 has a stepwise cross section which widens toward the front, as shown in FIG.

[0012]

According to the above-described device of the present invention, the cross-sectional shape of the inner peripheral wall of the passage 13 through which the ion beam passes is widened toward the front, so that the inner peripheral wall is knocked out by the impact of the ions. Contamination of the substrate 3 by the metallic material particles forming the passage 13 was significantly reduced.

This is because the cross-sectional shape of the inner peripheral wall surface of the passage 13 widens toward the forward direction and the ion beam spreads, and the inner peripheral wall of the passage 13 recedes, so that ions are allowed to enter the inner peripheral wall. Since the collision is less likely to occur, the probability of collision of the ions with the inner peripheral wall of the passage can be reduced, and the incident angle α of the ion with respect to the inner peripheral wall of the passage 13 (the angle between the normal direction of the wall surface and the arrival direction of the ions) is 90 °. The synergistic effect of being able to be in the vicinity significantly reduces the generation of metal particles from the inner peripheral wall surface of the passage 13.

That is, as reported in, for example, Applied Physics A 34,73-94 (1984) (hereinafter referred to as Material 1), when a particle is bombarded against a substrate, for example, Ni When Ne is bombarded on the substrate,
As shown in FIG. 6, when the incident angle α is around 90 °, the amount of sputtering, that is, the amount of protrusion of metal particles is almost zero.

In the structure shown in FIG. 4, ring-shaped wall surfaces 13a, 13b, ... Which are substantially orthogonal or oblique to the axis at the seams of the stairs are generated, so that the wall surfaces 13a, 13b ,. Although the collision of ions is large, the metal particles generated here hardly go to the front side, that is, toward the side of the ion-implanted substrate on which the ion implantation is performed, so that this has little effect on the characteristics of the substrate.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described with reference to FIG.

Also in this case, the vacuum container 1 is constructed so that the ion beam extracted from the ion source 2, that is, the charged particle beam 3 is bombarded with a required energy on the substrate 4 on which the intended ion implantation is performed. , The ions obtained from the ion source 2 are mass-analyzed by the analyzer magnet 6 in the analyzer chamber 5 only for the required ion species and introduced into the accelerating tube 7 to accelerate the first and second deflecting means. Horizontal and vertical deflections are performed by 8 and 9 so that the ion beam is bombarded with a required energy on the target substrate 4 and horizontal and vertical scanning is performed.

In the figure, 10 is a diffusion pump of an ion source, 11 is a diffusion pump of a beam line and an end station, and 12 is a Faraday cage.

The present invention relates to, for example, in such an ion implantation apparatus, in the passage 13 thereof, for example, in the analyzer chamber 5, and also in the passage 13 having the bent portion 14 of the beam line on the exit side of the second deflecting means 9. The inner peripheral wall has a cross-sectional shape that widens toward the front.

That is, as shown in FIG. 2, the inner peripheral wall of the passage 13 has a parabolic or hyperbolic shape of a quadratic curve of a cross section that widens toward the front.

Alternatively, for example, as shown in FIG.
As shown in FIG.

Alternatively, as shown in FIG. 4, the inner peripheral wall of the passage 13 has a stepwise cross section.

That is, these passages 13 are, for example, SU
The pipe of S forms, for example, rotational symmetry with respect to the axis of the ion beam (charged electron beam) 3 in the passage 13, and the cross-section including this axis has a trumpet shape in FIG. A frusto-conical surface or a stepped shape in which a plurality of frusto-conical surfaces or trumpet-shaped portions in FIG.

In this case, the wall surface 13 generated at that stage
It is possible to form a and 13b on a surface in which the incident angle of ions toward this is not as vertical as possible.

In the structure shown in FIG. 4, ring-shaped wall surfaces 13a, 13b, ... Which are substantially orthogonal or oblique to the axis are formed at the joints of the stairs. Although it becomes large, the metal particles generated here hardly go to the front side, that is, toward the ion-implanted substrate side where the ion implantation is performed, so that this has little influence on the characteristics of the substrate.

In this step-like structure, by making the inner diameters of the ring-shaped wall surfaces 13a, 13b, ... gradually larger toward the front side, it is possible to reduce the impact of the ions on them.

According to the above-described structure of the present invention, the bent or curved portion of the ion passage having a high ion impact probability against the inner peripheral wall surface of the passage 13 has a shape that widens toward the front. As is clear from the above, it is possible to suppress the generation of the metal particles in a portion which has an incident angle where a large amount of the metal particles are generated, and it is possible to effectively avoid the metal contamination of the base body 3.

The present invention is not limited to the case of being applied to the ion implanter having the configuration shown in FIG. 1, but can be applied to other various types of ion implanters and other various charged particle accelerators. .

[0029]

According to the above-described device of the present invention, the cross-sectional shape of the inner peripheral wall of the passage 13 through which the ion beam passes is made wider toward the front side, so that the passage 13 due to the impact of the ions on the inner peripheral wall is formed. Contamination of the base body 3 by the constituent metal material particles was remarkably reduced.

This is because the cross-sectional shape of the inner peripheral wall surface of the passage 13 widens toward the forward direction and the ion beam spreads. At the same time, the inner peripheral wall of the passage 13 recedes so that the ions come to the inner peripheral wall. Since the collision is less likely to occur, the probability of collision of the ions with the inner peripheral wall of the passage can be reduced, and the incident angle α of the ion with respect to the inner peripheral wall of the passage 13 (the angle between the normal direction of the wall surface and the arrival direction of the ions) is 90 °. By virtue of the synergistic effect of being able to be in the vicinity, generation of metal particles from the inner peripheral wall surface of the passage 13 can be reduced.

Therefore, when the present invention is applied to, for example, an ion implantation apparatus used in the process of manufacturing a semiconductor device, it is possible to avoid contamination of the ion-implanted semiconductor substrate by metal impurities and deterioration of characteristics.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of a device of the present invention.

FIG. 2 is a sectional view of an example of a charged particle passage in the device of the present invention.

FIG. 3 is a cross-sectional view of another example of the charged particle passage in the device of the present invention.

FIG. 4 is a sectional view of an example of a charged particle passage in the device of the present invention.

FIG. 5 is a schematic configuration diagram of a conventional device.

FIG. 6 is a diagram showing an incident angle dependency of a sputtering amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Ion source 3 Charged beam 4 Ion implantation substrate 5 Analyzer chamber 6 Analyzer magnet 7 Accelerating tube 8 First deflecting means 9 Second deflecting means 13 Passage 14 Bending or bending section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 21/265

Claims (3)

[Claims] 1. A charged particle accelerator according to claim 1, wherein an inner peripheral wall of a passage through which the charged particles in the vacuum container pass has a cross-sectional shape that widens toward the front. 2. A charged particle accelerating device, wherein the inner peripheral wall of the passage has a quadratic curve shape in a cross section that widens toward the front. 3. A charged particle accelerating device, wherein an inner peripheral wall of the passage has a stepwise cross section that widens toward the front.