JPH01274352A - Ion implantation device - Google Patents

Abstract

PURPOSE:To make it possible to exhibit the ion implantation performance sufficiently by corresponding the form of an electrode to the form of an ion beam, increasing the convergent force of the ion beam when the ion beam is passed through the electrode, and controlling the dispersion of the ion beam. CONSTITUTION:An ion beam 10 passing through the beam passing center port of an accelerating electrode 2 disposed in an accelerating tube is accelerated by the potential difference between accelerating electrodes after entered into the accelerating tube. As the ion beam 10 has an elliptic sectional form, the center port 2H of the accelerating electrode 2 also has the similar elliptic form corresponding to the beam form and a size enough to pass the beam easily therethrough. Therefore, the distance from the accelerating electrode 2 to the outer circumference of the beam 11 is equal in all positions thereof, never affecting the accelerating effect, and the extension of the beam diameter by the dispersion of the ion beam can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an ion implantation method used for injecting impurity ions into a semiconductor wafer to diffuse desired impurities into the wafer in the manufacturing process of semiconductor devices. Regarding equipment.

[Conventional technology]

FIG. 3 shows a schematic side view of a general ion implantation device.

In the figure, there are five accelerating electrodes 2a to 2e in the accelerating tube 1.
are arranged, and the electrodes 2a to 2e are applied with accelerating voltages of different values divided by the series voltage dividing resistor R from the accelerating voltage foot 7, and the ion beam 8 incident from the left side of the accelerating tube 1 is The light is accelerated by the electrodes 2a to 2e, passes through the center hole of each electrode, and is shaped through the aperture 5, and then enters the Q lens 6.

[Problem to be solved by the invention]

In the conventional acceleration tube described above, the shape of the electrode is a circular ring 4 as shown in the plan view of FIG. 4, so due to the diverging nature of the ion beam, the acceleration tube As the diameter of the ion beam at the exit increases, the ion beam collides with the aperture located between the exit of the accelerating tube and the Q lens, causing a loss of the ion beam corresponding to the area ratio. In addition, the collision has the disadvantage that particles such as secondary electrons are emitted into the beam line, adversely affecting the ion beam and impairing the ion implantation function.

[Means to solve the problem]

The accelerating tube of the ion implantation apparatus of the present invention is provided with an electrode having a central hole for beam passage that has a similar shape to the cross-sectional shape of the ion beam to be focused.

〔Example〕

Next, the present invention will be explained by examples.

FIG. 1(a) is a plan view showing one of the acceleration electrodes 2 arranged in the acceleration tube according to the first embodiment of the present invention, and FIG.
) is a cross-sectional view of the ion beam 10 passing through the beam passage center hole of the accelerating electrode in FIG.

In FIGS. 1A and 1B, the ion beam 10 is accelerated by the potential difference between the acceleration electrodes after entering the acceleration tube as shown in FIG. Since the ion beam 10 has an oval cross-sectional shape as shown in FIG. It has a size that allows the beam to pass through it easily.

Therefore, the distance to the accelerating electrode 2 is equal at all positions on the outer periphery of the beam 10, and it is possible to prevent the ion beam from diverging and expanding the beam diameter without adversely affecting the acceleration effect.

FIGS. 2(a) and 2(b) are a plan view of an accelerating electrode and a cross-sectional view of an ion beam according to a second embodiment of the present invention.

In FIGS. 2(a) and 2(b), the cross-sectional shape of the ion beam 20 is rectangular, and correspondingly, the beam passage center hole 3H of the electrode 3 is also large enough to allow the beam 20 to pass through easily. And they are similar rectangles. Therefore, in this example as well, the acceleration effect does not have any adverse effects, and it is possible to prevent the ion beam from divergent and the beam diameter from expanding.

〔Effect of the invention〕

As explained above, the present invention makes the shape of the electrode correspond to the shape of the ion beam, so that when the ion beam passes through the electrode, the ion beam is In order to increase the focusing power of the ion beam and suppress the divergence of the ion beam, it is possible to prevent the ion beam from colliding with the seven perchers and emitting particles such as secondary electrons into the beam line, which would have a negative impact on the ion beam. This has the great effect of making effective use of the ion beam and fully demonstrating the ion implantation function.

[Brief explanation of the drawing]

1(a) and 2(a) are plan views of one accelerating electrode of an accelerating tube in a first embodiment and a second embodiment of the present invention, respectively, and FIG. 1(b) and FIG. Figure (b) is a cross-sectional view of the ion beam passing through the center hole of the electrode in figure (a), Figure 3 is a block diagram showing the schematic configuration of a general ion implantation device, and Figure 4 is the same as that shown in Figure 3. FIG. 3 is a plan view of one accelerating electrode. 1...Acceleration tube, 2,2a-2e, 3,4...Group/acceleration type IT, 5...Aperture, 6...
...Q lens, 7... Acceleration power supply, 8, 10,
20. River...Ion beam. Agent Patent Attorney Oto Uchihara Figure 3

Claims (1)

[Claims] An ion implantation apparatus having an acceleration tube for accelerating an ion beam, characterized in that a central hole of an acceleration electrode of the acceleration tube through which the ion beam passes has a shape similar to a cross-sectional outline of the ion beam. Ion implanter.