JP2785297B2 - Ion implanter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called parallel scanning type ion implantation apparatus that performs parallel scanning of an ion beam in an X direction and a Y direction orthogonal thereto.

[Conventional technology]

In a conventional ion implantation apparatus that scans an ion beam at an angle in the X direction and the Y direction, there is a problem that an implantation angle differs depending on a position in a target surface. To solve this problem, a so-called parallel scanning type ion implantation is used. Equipment is being developed.

 FIG. 3 shows a conventional example of such a device.

That is, in this apparatus, the spot-shaped ion beam 4 extracted from the ion source 2 and subjected to mass analysis by the analysis electromagnet 6 and acceleration by the acceleration tube 8 is applied with a scanning voltage (triangular wave voltage) having an opposite phase to each other. The two sets of X scan electrodes 10 and 12 cooperate to electrostatically scan in the X direction (for example, in the horizontal direction; the same applies hereinafter) and apply scanning voltages (triangular wave voltages) having opposite phases to each other. By the cooperation of the Y scanning electrodes 14 and 16, electrostatic parallel scanning is performed in the Y direction (for example, the vertical direction; the same applies hereinafter).

Then, the entire surface of the target (for example, wafer) 18 is irradiated with the ion beam 4 scanned in parallel in both the X and Y directions, thereby performing ion implantation over the entire surface of the target 18 at a constant angle.

[Problems to be solved by the invention]

However, in such an ion implanter, twice the number of scan electrodes 10, 1 is used, which is twice that of a normal ion implanter.
Since 2, 14, and 16 must be provided, there is a problem that the beam line length becomes longer and the device becomes longer.

Incidentally, when the length of the ion implantation apparatus becomes large, for example, in a semiconductor manufacturing apparatus, since the ion implantation apparatus is the largest, even a clean room or a building for accommodating the ion implantation apparatus becomes large.

Therefore, an object of the present invention is to reduce the beam line length of such a parallel scanning type ion implantation apparatus.

[Means for solving the problem]

In order to achieve the above object, the ion implantation apparatus of the present invention, in summary, provides an acceleration means on the downstream side of the Y scanning means for scanning the ion beam in parallel in the Y direction, and further provides the ion beam in the ion beam X direction on the downstream side. X scanning means for performing parallel scanning is provided.

[Action]

According to the above configuration, the parallel scanning of the ion beam in the Y direction is performed on the low energy side on the upstream side of the accelerating means. Therefore, when a predetermined scanning width is obtained, the Y scanning means needs to be operated because the energy of the ion beam is low. The lengths of the two sets of Y-scanning electrodes to be configured can be reduced.

〔Example〕

FIG. 1 is a plan view showing an ion implantation apparatus according to one embodiment of the present invention, and FIG. 2 is a perspective view partially showing the vicinity of a Y scanning electrode and an acceleration tube in FIG. Hereinafter, differences from the conventional example will be mainly described.

In this embodiment, the analysis electromagnet 6 as described above is used.
Y scanning means is provided on the downstream side of.

This Y scanning means includes a Y scanning power supply 27 and two sets of scanning voltages (triangular wave voltages) having opposite phases applied thereto.
Y-scanning electrodes 24 and 26 are located on the upstream and downstream sides with respect to the beam traveling direction, respectively.
Are scanned in parallel in the Y direction.

On the downstream side of the Y-scanning means, an accelerating tube 28 is provided as an accelerating means for accelerating the ion beam 4 which has been scanned in parallel and has become a band.

Referring mainly to FIG. 2, the acceleration tube 28 has a required number of electrodes 28a each having an elongated slot 28b in the Y direction, and a DC voltage is applied between the electrodes 28a from an acceleration power source (not shown). Thereby, the ion beam 4 can be electrostatically accelerated to a required energy. Incidentally, uniform acceleration of such a band-like ion beam 4 can be relatively easily performed, as in the case of the conventional spot-like ion beam 4.

Further, X scanning means is provided on the downstream side of the acceleration tube 28.

The X scanning means includes an X scanning power supply 23 and two sets of scanning voltages (triangular wave voltages) having opposite phases applied thereto.
X scan electrodes 20 and 22 are located upstream and downstream of each other with respect to the beam traveling direction.
Are scanned in parallel in the X direction.

Then, the ion beam 4 scanned in parallel in the X and Y directions as described above is transferred to the target held by the holder 30.
Irradiation is performed on the entire surface of 18. Therefore, ion implantation is performed over the entire surface of the target 18 at a constant angle. 32
Is a holder driving device having a function of rotating the holder 30 as shown by an arrow R, for example.

According to the above configuration, the parallel scanning of the ion beam 4 in the Y direction is performed on the low energy side upstream of the accelerating tube 28 unlike the conventional example after acceleration by the accelerating tube 8. When obtaining a predetermined scanning width (in other words, deflection angle),
Since the energy of the ion beam 4 is low, the Y scan electrode 24
And 26 can be shorter than conventional Y scan electrodes 14 and 16.

In general, the deflection angle θ of the scanning electrode is as follows: θ = tan ⁻¹ (lV / 2dE) where l is the scanning electrode length, d is the electrode interval, V is the scanning voltage, and E is the energy of the ion beam. It can be seen from the expression.

As a result, the beam line length can be reduced as compared with the conventional example shown in FIG. 3, and the ion implantation apparatus can be prevented from becoming longer. As a result, the size of a clean room or building that houses the ion implantation apparatus can also be reduced.

Since this ion implantation apparatus does not use mechanical scanning, but scans the ion beam 4 electrostatically in both X and Y directions, the ion beam 4 moves on the target 18. Is fast and therefore does not cause an excessive temperature rise of the target 18.

Also, as in this embodiment, during ion implantation,
At the same time, the target 18 may be rotated. In such a case, the injection uniformity in the plane of the target 18 can be improved.

In this specification, the X direction and the Y direction represent only two orthogonal directions. Therefore, for example, the X direction can be viewed as a horizontal direction, a vertical direction, or a direction inclined from them. You can also see.

〔The invention's effect〕

As described above, according to the present invention, the parallel scanning in the Y direction of the ion beam is performed on the low energy side on the upstream side of the accelerating means, so that the Y scanning means is configured as the energy of the ion beam is low. The length of the two sets of Y scan electrodes can be reduced. As a result, the beam line length can be shortened as compared with the conventional example, and the ion implantation apparatus can be prevented from becoming longer.

[Brief description of the drawings]

FIG. 1 is a plan view showing an ion implantation apparatus according to one embodiment of the present invention. FIG. 2 is a perspective view partially showing the Y scanning electrode and the periphery of the acceleration tube in FIG. FIG.
It is a top view which shows an example of the conventional parallel scanning type ion implantation apparatus. 4 ... Ion beam, 18 ... Target, 20,22 ... X
Scan electrode, 23 ... X scan power supply, 24,26 ... Y scan electrode, 2
7 ... Y scanning power supply, 28 ... Acceleration tube.

Claims (1)

(57) [Claims] An ion beam is electrostatically scanned in the Y direction. The ion beam has two sets of Y scan electrodes located upstream and downstream with respect to the beam traveling direction. Scans in parallel the ion beam emitted from
A scanning unit, an acceleration unit for accelerating the ion beam parallel-scanned by the Y scanning unit, and two sets of two sets for electrostatically scanning the ion beam accelerated by the acceleration unit in the X direction orthogonal to the Y direction. X-scanning electrodes that are located on the upstream side and the downstream side with respect to the beam traveling direction, and are provided with X-scanning means for performing parallel scanning in the X-direction on the ion beam emitted from the pair of X-scanning electrodes on the downstream side. Ion implanter.