JPH0563898B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion beam implanter that implants ions into a sample by deflecting and scanning an ion beam.

[Conventional technology]

In order to uniformly implant ions into a sample in an ion implanter that uses medium current or less, the ion beam is conventionally deflected by a deflection scanning electrode installed in front of a sample disk that holds the sample, and Methods of electrostatically scanning an ion beam over an ion beam are well known. However, in conventional ion implanters, when the ion beam is scanned and deflected, the depth of the implanted layer changes because the angle between the ion beam and the sample is different between the center and the edge of the implanted sample. Therefore, there is a drawback that it is difficult to form an injection layer having a designed depth over the entire sample. (Solid
Solid State Technology
Technolojy, Vol21, Noll, November (1978),
PP61-67). As a method to avoid this, there is a method in which the ion beam is deflected and scanned enough to scan the entire surface of the sample to be implanted, and then deflected again to create a parallel ion beam. However, when this method is used, in the case of electrostatic scanning, the distance between the re-deflecting electrodes for re-deflecting the sample needs to be the same as that of the sample to be injected, which has the disadvantage that the applied signal voltage becomes high. This drawback is that the larger the sample to be injected, the higher the voltage needs to be. A detailed description will be given below with reference to the drawings.

FIG. 3 is a configuration diagram of an electrostatic scanning portion of a conventional ion implantation device. As shown in Fig. 3, the ion beam 11 is extracted by an electromagnetic lens, subjected to mass analysis, accelerated, and then shaped by a power-saving lens (not shown). When passing through the Y deflection electrode 12 consisting of The reference triangular wave 12b generated by the Y sweep oscillator 12a is converted into a triangular wave 12d whose polarity is inverted by the polarity converter 12c for application to the negative electrode of the Y electrode 12. In order to obtain a voltage sufficient to scan in the Y-axis direction, the amplifier 12e converts the voltage into a high-voltage triangular wave 12f, which is applied to the negative electrode of the Y-electrode 12. on the other hand,
The triangular wave applied to the positive electrode of the Y electrode 12 is the triangular wave 12 generated by the Y sweep oscillator 12a.
b is immediately converted into a high voltage triangular wave 1 by amplifier 12g.
2h and applied to the positive electrode parallel to and opposite the negative electrode of the Y electrode 12.

The ion beam 15 deflected by the Y electrode 12 so as to scan in the Y-axis direction enters the X-deflection electrode 13 to scan in the X-axis direction, and is further deflected and scanned. Similar to the Y electrode 12, the X sweep oscillator 13a
The reference triangular liquid 13b generated is turned into a triangular liquid 13d whose polarity is reversed by a polarity converter 13c in order to be applied to the negative electrode of the X electrode 13, and then the ion beam 15 is applied to the negative electrode of the In order to make the voltage sufficient for scanning, it is made into a high voltage triangular wave by the amplifier 13e. Furthermore, for neutral ion removal, a bias voltage is applied to the X electrode together with a triangular wave in order to offset the ion beam 15 by about 7 degrees and accelerate it toward a sample disk 16 (not shown).

The ion beam is deflected to scan by the Y electrode 12 and the X electrode 13 (the ion beam 11 is shown in Figure 3).
15 is the Y-axis direction;
The sample disk 16 is scanned vertically and horizontally in the X-axis direction by the area required for injection.
6 and the ion beam 15 is the angle between the sample plate 16 and the ion beam 15.
The disadvantage is that the position of the ion beam 15 always changes depending on the position of the ion beam 15, and as mentioned above, a big problem has arisen in that the depth distribution of the implanted impurity changes depending on the implantation location.

As a means to solve the above problem, as shown in FIG. The ion beams 15a and 15b, which have been deflected and scanned by the X electrode 13, are deflected again by the re-deflection The voltages of the deflection signals 43b and 43f applied to the re-deflection
43e, ion implantation can be performed with the angle of inclination between the sample disk and the ion beam always kept constant. Although only the X-axis has been described, the same applies to the Y-axis.

[Problem that the invention seeks to solve]

The above-described conventional ion beam implantation apparatus has the disadvantage that the voltage applied when deflecting the ion beam again is high because the re-deflection electrode spacing is large. This is the voltage V to be applied to the deflection electrodes.
However, the formula V = 2EDd/Ll (where E is the beam energy, D is the distance between the re-deflection electrodes, d is the amount of deflection at the sample disk, L is the length of the re-deflection electrode, and l is from the center of the re-deflection electrode plate. distance to the sample disk), so D
When the distance between the re-deflection electrodes becomes large, a problem arises in that it is necessary to increase the voltage V to be applied.

An object of the present invention is to provide an ion beam implantation apparatus that deflects and scans ions without increasing the voltage applied to the deflection electrode, and in which the inclination angle between the ion beam and the sample disk is always constant.

[Means for solving problems]

The present invention is an ion implantation device that implants ions into a sample by deflecting and scanning an ion beam. The ion implantation apparatus is characterized in that a re-deflection electrode for re-deflecting the ion beam is oscillated in synchronization with the deflection waveform by a deflection angle with the point at which the ion beam is deflected and scanned as the origin.

[Effect]

In the present invention, the re-deflection scanning electrode, which performs deflection scanning again after deflection-scanning the ion beam, is oscillated in synchronization with a deflection signal applied to the deflection-scanning electrode by the angle of deflection scanning with the point at which the ion beam is deflected and scanned as the origin. By doing so, the re-deflection scanning electrode always scans the same as the deflection-scanned ion beam.
The interval between the re-deflection electrodes can be narrowed, and therefore an ion implantation device in which the inclination angle between the ion beam and the sample disk is always constant can be easily obtained without increasing the voltage applied to the re-deflection electrodes. .

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. As shown in FIG. 1, the ion beam 15 is extracted by an electromagnetic lens, subjected to mass analysis, accelerated, and then shaped by an electrostatic lens (not shown). It is deflected when it passes through an X-deflection electrode 13 consisting of an electrode. The reference triangular wave 13b generated by the X sweep oscillator 13a is converted into a triangular wave 13d whose polarity is reversed by a polarity converter 13c for application to the negative electrode of the X electrode 13, and then the ion beam 15 is In order to make the voltage sufficient to scan in the axial direction, it is converted into a high voltage triangular wave 13f by an amplifier 13e and applied to the negative electrode of the X electrode 13. On the other hand, regarding the triangular wave applied by the positive electrode of the X electrode 13, the reference triangular wave 13b generated by the X sweep oscillator 13a is immediately transmitted to the amplifier 1.
3g makes the high voltage triangular wave 13h and the X electrode 13
is applied to the negative electrode and the opposite positive electrode. In addition, in order to remove neutral ions, the ion beam is offset by about 7 degrees by applying a DC bias voltage to the deflection electrode (generally the X electrode) (not shown), as shown in Figure 3. This is the same as the conventional ion implanter shown. In the present invention, the ion beams 15, 15a, 15b deflected by the X electrode 13 are incident on the re-deflecting X electrode 17 which deflects the ion beam again. The re-deflection X electrode 17 is attached to the fulcrum 19 of the arm 18 attached to the re-deflection X electrode 17 so that the trajectory of the deflected ion beams 15, 15a, 15b always passes through the center of the opposing re-deflection The re-deflection X electrode is oscillated in synchronization with the signal from the X sweep transmitter 13a using, for example, a driver 18b having a cam mechanism. However, there is a triangular wave 1 between the sweep oscillator 13a and the driver 18b.
A signal processor 18a is provided for converting the voltage of the driver 3b into the input voltage of the driver 18b at an appropriate ratio. By taking such a measure, the electrode spacing of the re-deflection X electrodes 17 can be narrowed, since the spacing sufficient to scan the sample disk in the X-axis direction is no longer required.

The triangular wave applied to the re-deflection X electrode 17 is a reference triangular wave 13b generated by the X sweep oscillator 13a, which is amplified by amplifiers 17a and 17e in consideration of the electrode spacing and electrode length of the re-deflection X electrode, and its phase is changed by 180 degrees. It is sufficient to shift the voltage and apply it. Note that if the electrode spacing and electrode length of the re-deflection X electrode 17 are made the same as those of the X-deflection electrode, the amplifiers 17a and 17e become unnecessary, and the output of the amplifier applied to the X-deflection electrode is shifted in phase by 180 degrees to the re-deflection X electrode. Just apply it.

FIGS. 2a to 2c are schematic diagrams showing the relationship between the ion beam 15 and the re-deflection X electrode 17. FIG. As shown in FIG.
7 will be in the position shown in the figure. FIG. 2b shows a case where the ion beam 15 is not deflected, and the re-deflection electrode 17 is in the position as shown in the figure. FIG. 2c shows a case where the ion beam 15 is deflected to the opposite side from that shown in FIG. 2a, and the re-deflection electrode 17 is at the position shown in the figure.

〔Effect of the invention〕

As is clear from the above, this is an ion implanter that implants ions into a sample by deflecting and scanning an ion beam.
After the ion beam is deflected and scanned, it is again deflected and scanned.
In an ion implantation device where the inclination angle between the ion beam and the sample disk is always constant,
The re-deflection electrode for re-deflecting the ion beam is oscillated in synchronization with the deflection waveform by the deflection angle with the point at which the ion beam is deflected and scanned as the origin, and the ion beam is passed between the opposing re-deflection electrodes. This has the effect that the re-deflection scanning signal voltage can be lowered because the re-deflection electrode interval can be narrowed.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of an embodiment of the present invention, Figure 2a
-c are schematic diagrams showing the relationship between the re-deflection electrode 17 shown in FIG. 1 and the ion beam, and FIGS. 3 and 4 are configuration diagrams of a conventional ion beam implantation apparatus. 11, 15, 15a, 15b, 45, 45a,
45b...Ion beam, 12...Y deflection electrode,
12a, 13a...sweep transmitter, 12c, 13
c, 17c, 43c...Polarity converter, 12e, 1
2g, 13e, 13g, 17a, 17e, 43
a, 43e...Amplifier, 16...Sample board, 17,
43...Redeflection X electrode, 18...Realignment deflection electrode swing arm, 18a...Transducer, 18b...Driver.

Claims (1)

[Claims] 1 In an ion beam implanter where the ion beam is deflected and scanned and then deflected again so that the angle of inclination between the ion beam and the sample disk is always constant, a re-deflection electrode is used to deflect the ion beam again. An ion beam implanter characterized in that the ion beam implanter is configured to oscillate in synchronization with a deflection waveform by an amount corresponding to a deflection angle with a point at which the deflection is scanned as an origin.