JPH03233845A - Ion injecting device - Google Patents

Abstract

PURPOSE:To compensate the gradient and the distortion of ion beam easily by forming a waveform of the voltage to be generated in an optional waveform generating power source so that the voltage to be applied to a deflecting electrode is high at a point that the deflection of the ion beam scanning in the X direction is smaller than the predetermined reference and that the voltage to be applied to the deflecting electrode is low at a point that a change is larger than the predetermined reference. CONSTITUTION:An optional waveform generating power source 20 for generating the voltage in optional waveform synchronized with the scanning voltage to be outputted from a scanning power source 12 is provided so that the voltage thereof is overlapped with the deflecting voltage to be outputted from a deflecting power source 8. A waveform of the voltage to be generated by this optional waveform generating power source 20 is formed so that the voltage to be applied to a deflecting electrode 6 is high at a point that the deflection of the ion beam 2 scanned in the X direction is smaller than the predetermined reference and that the voltage to be applied to a deflecting electrode 7 is low at a point that the deflection is larger than the predetermined reference. The ion beam 2 scanned in the X direction can be thereby made to approach the predetermined reference over the whole area, and the gradient and the distortion of the ion beam 2 can be compensated.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention electrically scans an ion beam and
Mechanically scanning the target in a direction perpendicular to it;
The present invention relates to a so-called hybrid scan type ion implantation device.

[Conventional technology]

A conventional example of this type of ion implantation apparatus is shown in FIG.

This ion implanter is of a so-called parallel scan type, and spot-shaped ion beams 2 are drawn out from an ion source (not shown) and subjected to mass analysis, acceleration, etc. as necessary, and are mutually transmitted from a scanning power source 12. By the cooperation of two sets of scanning electrodes 4 and 10 to which scanning voltages (triangular wave voltages) having a phase difference of 180 degrees are applied, that is, by deflecting the ion beam 2 deflected on one side in the opposite direction by the same angle on the other side. , a wide ion beam (
I am trying to create 2 parallel beams. If parallel beams are not required, the scanning electrode 10 on the downstream side is not necessary.

A set of deflection electrodes 6 to which a direct current deflection voltage is applied from a deflection power source 8 is provided between the rescanning electrodes 4.1o. The neutral beam is deflected by a required angle (for example, several degrees) in the vertical direction (the same applies hereinafter), and the neutral beam traveling straight is separated so that the target ion beam 2 passes through the opening 14a of the mask 14 provided on the downstream side. ing.

A target (for example, a wafer) 16 is held by a holder (not shown) within the irradiation area of the ion beam 2 that has passed through the mask 14, and is mechanically scanned in the Y direction by a drive device 18. By cooperating with the scanning in the X direction, ions are implanted uniformly over the entire surface of the target 16.

[Problems to be Solved by the Invention] In the above-described ion implantation apparatus, the ion beam 2 on the downstream side of the deflection electrode 6 may be affected by, for example, It may be tilted as shown in FIG. 7(A), or it may be distorted (bowed) as shown in FIG. 7(B) or 7(C). 3 in the figure is the center line in the X direction of the ion beam 2 in the normal state.

If the ion beam 2 is tilted or distorted as described above, for example, uniformity of implantation into the target 16 in the X direction cannot be ensured. Also, the ion beam 2 is connected to the mask 1.
4, and its utilization efficiency decreases.

In the above case, conventionally the deflection electrode 6, the scanning electrode 4,
The solution was to make corrections such as changing the shape of O and adjusting the mounting position, but since these deflection electrodes 6 and scanning electrodes 4 and 10 are kept in a vacuum, such corrections are impossible. This process must be performed by breaking the vacuum, which is extremely troublesome.

Therefore, the main object of this invention is to provide an ion implantation apparatus that can easily correct the above-mentioned ion beam inclination and distortion.

[Means to solve the problem]

In order to achieve the above object, the ion implantation apparatus of the present invention includes an arbitrary waveform generation power source that generates an arbitrary waveform voltage synchronized with the scanning voltage output from the scanning power source, and the voltage is output from the deflection power source. The waveform of the voltage provided to be superimposed on the deflection voltage and generated by this arbitrary waveform generation power source is the voltage applied to the deflection electrode at the time when the deflection of the ion beam scanned in the X direction is smaller than a predetermined reference. is set high, and the voltage applied to the deflection electrode is lowered when the deflection is larger than a predetermined reference.

[Effect]

Corresponding to one cycle of the scanning voltage output from the scanning power supply,
The ion beam makes one round trip in the scanning range in the X direction. In other words, the scanning voltage and the position of the ion beam in the X direction are 1
It corresponds to 1.

Therefore, by generating a voltage in synchronization with this scanning voltage and having the above waveform using an arbitrary waveform generation power supply, and superimposing it on the deflection voltage output from the deflection power supply, a voltage that is scanned in the X direction can be generated. The ion beam can be brought close to a predetermined standard over its entire area. That is, the tilt and distortion of the ion beam can be corrected.

〔Example〕

FIG. 1 is a diagram partially showing an ion implantation apparatus according to an embodiment of the present invention. The same reference numerals are given to the same or corresponding parts as in the conventional example shown in FIG. 6, and the differences from the conventional example will be mainly explained below.

In this embodiment, an arbitrary waveform voltage V! synchronized with the scanning voltage vX outputted from the scanning power supply 12 mentioned above is used. The arbitrary waveform generation power supply 20 that generates the above-mentioned deflection power supply 8
are inserted in series. For synchronization, the scanning power supply 12
A synchronizing signal SY is extracted from the synchronous signal SY and is supplied to the arbitrary waveform generating power supply 20.

In this way, the voltage V2 generated in the arbitrary waveform generation chamber #20 is superimposed on the voltage V1 outputted from the deflection power supply 8, and the resulting voltage v3 (=v, +V2) is applied to the aforementioned set of deflection The voltage is applied to the electrode 6.

The arbitrary waveform generation power supply 20 includes, for example, a waveform data memory 201. as shown in FIG. It includes a D/A converter 202 and a high voltage amplifier 203.

The waveform data memory 201 digitally stores various waveform data, and can output arbitrary waveform data in synchronization with the synchronization signal SY.

The D/A converter 202 converts the waveform data output from the waveform data memory 201 into analog and outputs the analog waveform.

The high voltage amplifier 203 voltage amplifies the analog waveform output from the D/A converter 202 to generate the voltage V2. Further, in this high voltage amplifier 203, this voltage V2 is superimposed on the voltage V supplied from the deflection power supply 8 to generate the voltage V3.

In an ion implanter like the one shown in Fig. 1, the scanning power supply I
Corresponding to one period of the scanning voltage Vx output from the ion beam 2, the ion beam 2 makes one round trip in the scanning range in the X direction. In other words, there is a one-to-one correspondence between the scanning voltage vx and the position of the ion beam 2 in the X direction. For example, points a and b on the ion beam 2 shown in FIGS. 7(A) to C), points a%b on the scanning voltage VX shown in FIGS. 3 to 5, and the scanning voltage vX Points a and b on voltage V□ which are synchronized with
correspond to each other.

Therefore, for example, when the ion beam (the ion beam that has been scanned in the X direction and has become wider) 2 is tilted as shown in FIG. As shown in FIG. 3, the waveform is shaped like a triangular wave with a peak at point a and a valley at point a. The magnitude of this voltage (2) at each point is preferably set to a magnitude that corrects the deviation of each point of the ion beam 2 from the center 11A3. In this way, around the front and back of point a,
The voltage applied to the deflection electrode 6 is the base voltage V
, so the ion beam 2 is strongly deflected and approaches the center line 3, and near the front and back of the dot,
Since the voltage v3 is lower than the voltage V, the ion beam 2 is weakly deflected and approaches the center line 3, and as a result, the inclination of the ion beam 2 is corrected and becomes aligned along the center line 3.

Furthermore, when the ion beam 2 is bent downward as shown in FIG. 7(B), the waveform of the voltage v2 generated by the arbitrary waveform generation power source 20 peaks at points a and b as shown in FIG. Make it a sinusoidal waveform. The magnitude of this voltage v2 at each point is also preferably set to a magnitude that corrects the deviation from the center line 3 at each point of the ion beam 2.

In this way, in the vicinity of points a and b, the voltage V applied to the deflection electrode 6 becomes higher than the base voltage V, so the ion beam 2 is strongly deflected and approaches the center line 3. So, near the middle between points a and b,
Since the voltage V, becomes lower than the voltage v1, the ion beam 2 is deflected weakly and approaches the center line 3, and as a result, the curvature of the ion beam 2 is corrected and becomes aligned along the center line 3.

Furthermore, when the ion beam 2 is bent upward as shown in FIG. 7(C), the waveform of the voltage vt generated by the arbitrary waveform generation power supply 20 has valleys at points a and b as shown in FIG. Make it a sinusoidal waveform. The magnitude of this voltage (2) at each point is also preferably set to a magnitude that corrects the deviation from the center line 3 at each point of the ion beam 2.

In this way, in the vicinity of points a and b, the voltage V applied to the deflection electrode 6 is lower than the base voltage V1, so the ion beam 2 is weakly deflected and approaches the center line 3. , and around the middle between points a and b,
Since the voltage V is higher than the voltage 1, the ion beam 2 is strongly deflected and approaches the center line 3, and as a result, the curvature of the ion beam 2 is corrected and it comes to follow the center line 3.

In any case, in order to completely bring the ion beam 2 corrected into a straight line to the center line 3, the magnitude of the deflection voltage vl output from the deflection power source 8 may be adjusted as necessary. good.

In this way, according to this embodiment, the arbitrary waveform generation power source 2
By selecting the waveform of the voltage 2 generated at 0 as described above, it is possible to correct the tilt and distortion of the ion beam 2, and the deflection electrode 6 and the scanning electrode 4. This correction can be performed more easily than when performing correction work.

By correcting the ion beam 2 along the center line 3, the uniformity of implantation into the target 16 in the X direction is improved. In addition, the ion beam 2 that is lost due to hitting the mask 14 can be guided to the target 16,
The utilization efficiency of the ion beam 2 is improved.

Note that, unlike the above example, the deflection electrode 6 may be arranged upstream of the scanning electrode 4 or downstream of the scanning electrode IO.

In addition, when creating parallel beam 2, two sets of scanning electrodes 4 are used.
In some cases, scanning voltages having a phase difference of 180 degrees are supplied to the scanning power supplies 10 and 10 from different scanning power supplies, but even in that case, the scanning voltages output from both scanning power supplies are always synchronized.
The synchronizing signal SY mentioned above may be taken out from either power source.

In addition, in this specification, the X direction and the Y direction only represent two orthogonal directions, and therefore, for example, whether the X direction is viewed as a horizontal direction, a vertical direction, or even a direction tilted from them. You can also look at it as

〔Effect of the invention〕

As described above, according to the present invention, by selecting the waveform of the voltage generated by the arbitrary waveform generating power source as described above, it is possible to easily correct the inclination and distortion of the ion beam.

[Brief explanation of drawings]

FIG. 1 is a diagram partially showing an ion implantation apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of the configuration of an arbitrary waveform generation power source. 3 to 5 are diagrams showing examples of the waveforms of the scanning voltage and the voltage applied to the deflection electrodes, respectively. 6th
The figure is a diagram partially showing an example of a conventional ion implantation device. FIGS. 7(A) to 7(C) are diagrams showing examples of the inclination and distortion of the ion beam, respectively. 2... Ion beam, 43.6 Scanning electrode, 61. . Deflection electrode, 889. Deflection power supply, 10...Scanning electrode, 1
2...Scanning power supply, 16...Target, 18...
Drive device, 20...Arbitrary waveform generation power supply.

Claims (1)

[Claims] (1) A scanning electrode that electrically scans the ion beam in the X direction, a scanning power supply that supplies a scanning voltage to the scanning electrode,
An ion implantation device that includes a deflection electrode that deflects the ion beam in the Y direction orthogonal to the X direction, a deflection power supply that supplies a DC deflection voltage to the deflection electrode, and a drive device that mechanically scans the target in the Y direction. , an arbitrary waveform generation power supply that generates an arbitrary waveform voltage synchronized with the scanning voltage output from the scanning power supply is provided so that the voltage is superimposed on the deflection voltage output from the deflection power supply, and The waveform of the voltage generated by the waveform generation power source is changed by increasing the voltage applied to the deflection electrode at the time when the deflection of the ion beam scanned in the X direction is smaller than a predetermined reference, and when the deflection is larger than the predetermined reference. An ion implantation apparatus characterized in that the voltage applied to the deflection electrode is lowered.