JPH06349439A - Ion implanting device - Google Patents

Abstract

PURPOSE:To eliminate the useless part in the mechanical scanning of a wafer in the case where the angle of implantation is changed, and to improve the through-put. CONSTITUTION:In this ion implanting device, even in the case where the angle thetaof implantation is changed, a wafer 6 is always scanned mechanically within a surface in parallel with the surface thereof like an arrow W. In such a device, in the case where (d) means largeness of an ion beam, S means a diameter of the wafer, theta means an angle of implantation, and S means over-scanning width of the wafer at 0 degree of implantation angle, the wafer 6 is scanned mechanically at a scanning width L expressed by L=D+(d+2S)/costheta.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called hybrid scan type ion implantation apparatus which electrically scans an ion beam and mechanically scans a wafer in a direction intersecting with the ion beam, and more specifically, The present invention relates to a means for improving throughput by eliminating unnecessary portions in mechanical scanning of a wafer when the implantation angle is changed.

[0002]

2. Description of the Related Art FIG. 6 is a schematic view partially showing an example of a conventional ion implantation apparatus. This ion implantation apparatus electrically scans (for example, parallel scans) the ion beam 2 in the X direction (for example, horizontal direction; the same applies hereinafter) by an electrical scanning means (not shown) to guide it into the implantation chamber 4, and at the same time, the wafer 6
In the injection chamber 4 in the W direction intersecting the X direction (see FIG.
And see FIG. ) Mechanically scanning the holder 8 in the implantation chamber 4 for holding the wafer 6.
And a holder drive device 10 for scanning the holder 8 in the injection chamber 4 in the W direction.

In this example, the holder driving device 10 includes a vacuum seal bearing 12 provided on the side surface of the injection chamber 4, a main shaft 14 that penetrates the bearing 12 in the X direction, and the main shaft 14 outside the injection chamber. A reversible direct drive motor 16 having an output shaft coupled to an end thereof, a reversible direct drive motor 18 mounted so as to be orthogonal to the injection chamber inner end of the main shaft 14, and the direct drive motor The arm 22 is mounted so as to be orthogonal to the output shaft 18 and the reversible direct drive motor 24 is mounted so as to be orthogonal to the arm 22. The output shaft of the direct drive motor 24 The above-mentioned holder 8 is attached so as to be orthogonal to each other.

At the time of ion implantation, as shown by an arrow B, the motor 22 causes the arm 22 to reciprocate within a predetermined angle range, for example, by allocating the horizontal position. As a result, the wafer 6 held by the holder 8 is mechanically scanned in the W direction so as to draw an arc while facing the ion beam 2.

At this time, the implantation angle θ of the ion beam 2 with respect to the wafer 6 (that is, the angle formed by the center of the ion beam 2 and the vertical line standing on the wafer surface. It can be changed by rotating the motor 18, the arm 22, the motor 24, the holder 8 and the like around the center as indicated by arrow A. In that case, even if the implantation angle θ is changed, the wafer 6 is always mechanically scanned in a plane parallel to its surface (see FIG. 8 described later).

The motor 24 includes a holder 8 and a wafer 6.
Is used to rotate the arrow as indicated by arrow C.

A controller 30 controls the holder driving device 10, more specifically, the motors 16, 18 and 24 constituting the holder driving device 10.

[0008]

In the ion implantation apparatus as described above, the wafer 6 is scanned (that is, overscanned) so that the end portion thereof is slightly deviated from the ion beam 2. If this is not done, the amount of implantation will increase when the wafer 6 is reversed in the scanning direction, and it will not be possible to perform uniform ion implantation on the entire surface of the wafer 6.

The scan width required for overscanning the wafer 6 as described above depends on the implantation angle θ. That is, FIG. 7 shows the case where the implantation angle θ is 0 degree, the scanning width at this time is L _0, and FIG. 8 shows the case where the implantation angle θ is 60 degrees, and the scanning width at this time is L _1. , L ₀ <
It becomes L ₁ . This is because the ion beam 2 has a certain finite size, and as described above, even if the implantation angle θ is changed, the wafer 6 is always indicated by the arrow W in a plane parallel to the surface thereof.
This is because the mechanical scanning is performed as shown in (1), and the above-described overscan cannot be realized unless the scanning width is increased as the implantation angle θ increases.
Therefore, conventionally, the scanning width is fixed to the scanning width L ₁ at the maximum injection angle θ used.

However, in such a case, overscan can be always realized even if the implantation angle θ is changed, but if the implantation angle θ becomes small, the wafer becomes too large, for example, as indicated by reference numeral 6a in FIG. Since the scanning is performed with the scanning width L ₁ , the additional scanning is performed by L ₁ −L ₀ .

As a result, since the ion beam 2 is not injected into the wafer 6 and wasted during the extra scanning, the utilization efficiency of the ion beam 2 is lowered, and the throughput is lowered. is there.

Therefore, it is a main object of the present invention to provide an ion implantation apparatus capable of improving a throughput by eliminating a useless portion in mechanical scanning of a wafer when an implantation angle is changed.

[0013]

To achieve the above object, a first invention is an apparatus for electrically scanning an ion beam and mechanically scanning a wafer in a direction intersecting the scanning direction of the ion beam. The ion implantation angle of the ion beam with respect to the wafer is variable, and even if the implantation angle is changed, the ion implantation apparatus configured to always mechanically scan the wafer in a plane parallel to the surface thereof,
The size of the ion beam is d, the diameter of the wafer is D,
When the implantation angle is θ and the overscan width of the wafer when the implantation angle is 0 degree is S, the wafer is mechanically scanned with the scanning width L represented by L = D + (d + 2S) / cos θ. It is characterized by

The second aspect of the invention is to electrically scan the ion beam and mechanically scan the wafer in a direction substantially orthogonal to the scanning direction of the ion beam. In an ion implanter with a variable angle, the size of the ion beam is d, the diameter of the wafer is D, the implant angle is θ, and the implant angle is 0.
When the overscan width of the wafer in degrees is S, the wafer is mechanically scanned with a scanning width L represented by L = d + 2S + Dcosθ.

[0015]

In the first aspect of the invention, the scanning width becomes the smallest when the implantation angle is 0 degree, and the scanning width also increases as the implantation angle increases. As a result, an almost constant overscan width can always be realized even if the implantation angle is changed. As a result, it is possible to eliminate a wasteful part in the mechanical scanning of the wafer when the implantation angle is changed, and it is possible to effectively use the ion beam, so that the throughput is improved.

In the second invention, the implantation angle is 0.
Degree, the scanning width becomes the largest, and the scanning width becomes smaller as the implantation angle becomes larger. As a result, an almost constant overscan width can always be realized even if the implantation angle is changed. As a result, it is possible to eliminate a wasteful part in the mechanical scanning of the wafer when the implantation angle is changed, and it is possible to effectively use the ion beam, so that the throughput is improved.

[0017]

1 is a schematic view partially showing an ion implantation apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the scanning width of the wafer when the implantation angle in the apparatus of FIG. 1 is 0 degree. FIG. 3 is a schematic diagram showing the scanning width of the wafer when the implantation angle in the apparatus of FIG. 1 is larger than 0 degree. The same or corresponding portions as those of the conventional example shown in FIGS. 6 to 8 are designated by the same reference numerals, and the differences from the conventional example will be mainly described below.

In this embodiment, a control device 30a corresponding to the control device 30 of the conventional example performs the following control.

That is, the size of the ion beam (the diameter when the cross section of the ion beam 2 is circular, the diameter when the cross section of the ion beam 2 is square, the height in the direction orthogonal to the X direction, and the same below) is d, and the diameter of the wafer 6 is D, ion beam 2 for wafer 6
Of the wafer 6 when the implantation angle is θ and the implantation angle θ is 0 degree
S is the required overscan width of
The wafer 6 is mechanically scanned in the W direction with a scanning width L represented by.

[0020]

[Equation 1] L = D + (d + 2S) / cos θ

Specifically, the control as shown in the above equation 1 is performed by the control device 30a controlling the motor 18 in accordance with the injection angle θ to control the rotation angle thereof as indicated by the arrow B. Therefore, in the case of this embodiment, the scanning width L is specifically represented by the angle of rotation of the arm 22.

Further, in the control device 30a, the scanning width L is calculated by using the previously defined D, d, and S and the implantation angle θ given as the implantation condition, and performing the calculation of the equation 1 each time. The wafer 6 may be scanned with the obtained scanning width L, or a plurality of data (for example, in the form of a table) in which the implantation angle θ to be used and the scanning width L which is the calculation result of Equation 1 are associated with each other. (Data) is stored in the control device 30a in advance, and when the implantation angle θ is given, the scanning width L corresponding to the implantation angle θ is read and the wafer 6 is scanned with the scanning width L. good.

In the ion implanter of this embodiment,
When the injection angle θ is 0 degree, the scan width L becomes the smallest,
As the implantation angle θ increases, the scanning width L also increases accordingly. Thereby, even if the implantation angle θ is changed, an almost constant overscan width can be always realized. As a result, it is possible to eliminate a wasteful part in the mechanical scanning of the wafer 6 when the implantation angle θ is changed, and it is possible to effectively use the ion beam 2, and thus the throughput is improved.

FIG. 4 is a schematic view partially showing another example of the conventional ion implantation apparatus. This ion implanter electrically scans the ion beam 2 in the X direction by an electrical scanning means (not shown), and also causes the holder 8 and the wafer 6 to be in a Y direction (eg, a vertical direction; the same applies hereinafter) substantially orthogonal to the X direction. The holder driving device 32 mechanically scans. The control of the holder driving device 32 is performed by the control device 34.

Also in this ion implanter, the holder 8
By tilting (see FIG. 5), the implantation angle θ (see FIG. 5) of the ion beam 2 with respect to the wafer 6 can be changed.

Conventionally, in such an ion implantation apparatus, the implantation angle θ is always 0 ° (that is, in the figure, in order to always realize an overscan of a required overscan width S even if the implantation angle θ is changed. 4), the wafer 6 is scanned in the Y direction with the required scanning width L ₀ .

However, in such a scan having a constant scan width, the wafer 6 is additionally scanned as the implantation angle θ becomes larger than 0 degree, which is the same as the case of the conventional example shown in FIG. In addition, there is a problem that the utilization efficiency of the ion beam 2 is lowered, and eventually the throughput is lowered.

Therefore, in this embodiment, referring to FIG. 5, a control device 34 corresponding to the control device 34 of the above-mentioned conventional example.
In a, the following control is performed.

That is, similarly to the above, the size of the ion beam 2 is d, the diameter of the wafer 6 is D, the implantation angle of the ion beam 2 with respect to the wafer 6 is θ, and the implantation angle θ of the wafer 6 is 0 °. When the required overscan width is S, the wafer 6 is mechanically scanned in the Y direction with a scanning width L represented by the following equation 2.

[0030]

[Equation 2] L = d + 2S + D cos θ

In the control unit 34a, as in the case of the control unit 30a in the embodiment of FIG. 1, each time the scan angle L is calculated by using the given implantation angle θ, the calculation of the above-mentioned equation 2 is performed.
Alternatively, the controller 34a may obtain a plurality of data in which the implantation angle θ and the scanning width L, which is the calculation result of Equation 2, are related.
It may be stored in advance and the scanning width L corresponding to the implantation angle θ may be read out when the implantation angle θ is given.

In this embodiment, the scanning width L becomes the largest when the implantation angle θ is 0 °, and the scanning width L correspondingly decreases as the implantation angle θ increases. Thereby, even if the implantation angle θ is changed, an almost constant overscan width can be always realized. As a result, it is possible to eliminate a wasteful part in the mechanical scanning of the wafer 6 when the implantation angle θ is changed, and it is possible to effectively use the ion beam 2, and thus the throughput is improved.

[0033]

As described above, according to the present invention, the mechanical scanning width of the wafer is controlled according to the implantation angle, and a substantially constant overscan width can be always realized even if the implantation angle is changed. Therefore, it is possible to eliminate a wasteful part in the mechanical scanning of the wafer when the implantation angle is changed. As a result, it is possible to effectively utilize the ion beam and improve the throughput.

[Brief description of drawings]

FIG. 1 is a schematic view partially showing an ion implantation apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a scanning width of a wafer when the implantation angle is 0 ° in the apparatus of FIG.

FIG. 3 is a schematic view showing a scanning width of a wafer when the implantation angle is larger than 0 degree in the apparatus of FIG.

FIG. 4 is a schematic view partially showing another example of the conventional ion implantation apparatus.

FIG. 5 is a schematic view partially showing an ion implantation apparatus according to another embodiment of the present invention.

FIG. 6 is a schematic view partially showing an example of a conventional ion implantation apparatus.

FIG. 7 is a schematic diagram showing a scanning width of a conventional wafer when the implantation angle is 0 ° in the apparatus of FIG.

8 is a schematic view showing a scanning width of a conventional wafer when the implantation angle is 60 degrees in the apparatus of FIG.

[Explanation of symbols]

 2 Ion beam 6 Wafer 8 Holder 10 Holder drive device 30a Control device 32 Holder drive device 34a Control device

Claims (2)

[Claims] 1. An apparatus for electrically scanning an ion beam and mechanically scanning a wafer in a direction intersecting a scanning direction of the ion beam, wherein an implantation angle of the ion beam with respect to the wafer is variable, and In an ion implantation apparatus in which the wafer is always mechanically scanned in a plane parallel to the surface even if the implantation angle is changed, the size of the ion beam is d, the diameter of the wafer is D, and the implantation angle is θ. , Where S is the overscan width of the wafer when the implantation angle is 0 degree, the wafer is mechanically scanned with a scan width L represented by L = D + (d + 2S) / cos θ. Ion implanter. 2. Ion implantation for electrically scanning an ion beam and mechanically scanning a wafer in a direction substantially orthogonal to a scanning direction of the ion beam, wherein the ion beam implantation angle to the wafer is variable. In the apparatus, when the size of the ion beam is d, the diameter of the wafer is D, the implantation angle is θ, and the overscan width of the wafer when the implantation angle is 0 degree is S, a scan represented by L = d + 2S + Dcosθ An ion implanter characterized in that a wafer is mechanically scanned with a width L.