JP4691347B2 - Ion implanter - Google Patents

Description

  The present invention relates to an ion implantation apparatus, and more particularly to ion implantation that can stably obtain an ion beam having a relatively small spot size even at low energy and large current by adjusting the outer diameter of the ion beam in the horizontal and vertical directions. Relates to the device.

Various types of ion implantation apparatuses for accelerating ions from an ion source to a desired energy and implanting the ions on a solid surface such as a semiconductor have been put to practical use (see Patent Document 1).
Hereinafter, an example of a conventional ion implantation apparatus will be described with reference to FIG.
FIG. 6 is a plan view showing a schematic configuration of a conventional ion implantation apparatus.

As shown in FIG. 6, the main configuration of the ion implantation apparatus 100 includes an ion source 110, a mass separator 120, a mass separation slit 130, an acceleration / deceleration tube 140, a quadrupole lens 150, a scanner 160, and a collimator 170. is there.
In the figure, reference numeral 180 denotes a substrate serving as a target for implanting ions arranged in an end station (not shown).
B is an ion that travels around a central axis (hereinafter also referred to as “optical axis”), but may be referred to as “ion beam” or “beam” hereinafter.

In the following, supplementary explanation will be given sequentially on each of the main components of the ion implantation apparatus 100.
First, the ion source 110 is an apparatus that generates ions by stripping electrons from atoms and molecules, and draws out ions in the ion source 110 by applying a high voltage to a drawing port (not shown).

The mass separator 120 generates a magnetic field and / or an electric field by utilizing the property that charged particles such as ions and electrons are deflected in the magnetic field or electric field, and the ion species to be injected into the substrate 180. It is a device for specifying.
FIG. 6 shows a mass separator 120 of a type that selects ions B by the action of a magnetic field.

The acceleration / deceleration tube 140 is a device for accelerating or decelerating a desired ion species that has passed through the mass separation slit 130, but as shown in FIG. By applying an equal high voltage to the electrodes, and by the action of an electrostatic field, the ion beam B is accelerated or decelerated to a desired implantation energy.
The reason why the accelerating / decelerating tube 140 has an axisymmetric structure is that manufacture is easy.

The quadrupole lens 150 is installed between the acceleration / deceleration tube 140 and the scanner 160 as shown in FIG. 6 in order to adjust the beam spot shape of the ion beam B on the substrate 180.
The quadrupole lens 150 has a function of converging the ion beam B in a plane perpendicular to the traveling direction thereof, similarly to the case where the optical convex lens converges light.

However, the quadrupole lens 150 is orthogonal to the traveling direction of the ion beam B in the perpendicular plane, for example, in the horizontal direction (the direction horizontal to the paper surface of FIG. 6). In the vertical direction (direction perpendicular to the paper surface of FIG. 6), a diverging action is exerted.
That is, this point is significantly different from an optical convex lens that converges light in both the horizontal and vertical directions.

  Therefore, in the conventional ion implantation apparatus 100 shown in FIG. 6, usually two or three quadrupole lenses that converge in the horizontal direction and quadrupole lenses that converge in the vertical direction (the one shown in the figure is 2), and the beam B is converged in both horizontal and vertical directions.

There are mainly two types of quadrupole lens 150: an electrostatic quadrupole lens that converges the ion beam B by the action of an electrostatic field, and a magnetic quadrupole lens that converges the ion beam by the action of a static magnetic field. To do.
Further, as will be described later, the convergence force (divergence force) of the quadrupole lens 150 has a property proportional to the distance from the center, and therefore the convergence force (divergence force) becomes stronger toward the outside.

The scanner 160 generates a uniform external electric field in a direction orthogonal to the traveling direction of the ion beam B, and controls the ion deflection angle by changing the polarity and intensity of the electric field, as shown in FIG. Then, the ions B are scanned at a desired position on the implantation surface of the substrate 180 and uniformly implanted.
In the case shown in FIG. 6, scanning is performed at a high speed of about 1 kHz.

The collimator 170 uses the property that ions B, which are charged particles, are deflected in a magnetic field, and suppresses the spread of the beam by the difference in the path of each ion that constitutes the ion beam B. This is an apparatus that makes the light incident parallel to 180.
FIG. 6 shows the collimator 170, but it is not necessarily an essential component of the ion implantation apparatus 100.

  The substrate 180 is disposed in the end station and mechanically scanned at a relatively slow speed of about 1 Hz in a direction orthogonal to the direction in which the scanner 160 scans the ion beam B.

Next, the basic operation of the conventional ion implantation apparatus 100 will be described with reference to FIG.
In the conventional ion implantation apparatus 100, in order to perform ion implantation with a predetermined energy at a uniform density over the entire surface of the substrate B on which ions B are implanted, a predetermined energy is extracted from the ion source 110. The ion beam B thus deflected is deflected by the mass separator 120, and only predetermined ion species are sorted by the mass separation slit 130.

The selected ion beam B is accelerated or decelerated to a desired energy by the acceleration / deceleration tube 140 and, as described above, an external electric field having a period of about 1 kHz is applied to the scanner 160 and scanned on the scanning surface of the substrate 180. The
In the above description, the electrostatic type scanner 160 that scans the ion beam B with an external electric field is taken up. However, the scanner 160 may be a magnetic type instead of the electrostatic type.

  The depth at which the ions B enter the solid can be accurately controlled by the energy of the ions B. For example, when the dose distribution of the ion beam is monitored when the ion implantation apparatus 100 is started up, the implantation surface of the substrate 180 is obtained. By scanning the ion beam B, uniform ion implantation processing of a desired ion species can be easily performed.

By the way, with the miniaturization of semiconductor devices, an increase in beam current with low energy is also demanded in medium current ion implantation apparatuses.
Specifically, when the ion species is B + and the implantation energy is 10 keV, the current of the ion beam B needs about 1 mA.

On the other hand, ion implantation with a relatively high energy of about 150 to 200 keV, which is the original purpose of the medium current ion implantation apparatus, is also necessary.
For this reason, in the medium current ion implantation apparatus, ions B are once extracted from the ion source 110 with energy of about 30 keV, and necessary ion species are selected by the mass separator 120, and then accelerated or decelerated by the acceleration / deceleration tube 140. Therefore, it is converted into predetermined injection energy.

At this time, in order to perform mass separation efficiently, the ion extraction port of the ion source 110 is formed in a slit shape, the deflection surface of the beam B in the mass separator 120 is a surface orthogonal thereto, and the ion extraction port of the ion source 110 has a mass. A mass separation slit 130 is installed at a position where an image is formed by the separator 120.
For this reason, the optical properties of the mass-separated ion beam B are usually greatly different at two points orthogonal to the optical axis.

Non-Patent Document 1, Non-Patent Document 2, and the like are examples of actual measurement of the divergence angle of the beam B from the ion source 110 having the slit-shaped ion extraction port.
According to these, the width direction of the slit has a spread of about ± 1.0 ° to ± 2.0 °, but the spread of the slit in the longitudinal direction is about ± 0.5 °.
In the conventional ion implantation apparatus, the ion source outlet is a slit that is long in the vertical direction, and the ion beam B is extracted in the horizontal direction.

JP-A-8-213339 S.Ogata et al. Nucl. Instrum and Meth. A363 (1995) 468- T. Kunibe et al. Proceedings of 1998 Int. Conf. On Ion Implantation Technology, (1999) 424-

Next, in order to clarify the problems of the conventional ion implantation apparatus, a computer simulation based on the trajectory calculation program is performed on the trajectory of the ion beam, and the first and second calculation results are shown in FIGS. It is shown in FIG.
FIG. 7 is a diagram showing an ion beam envelope of a conventional ion implantation apparatus, in which energy is high.
FIG. 8 is a diagram showing an ion beam envelope of a conventional ion implantation apparatus, in which energy is low.

First, the first calculation result of the computer simulation based on the trajectory calculation program is analyzed for the trajectory of the ion beam in the conventional ion implantation apparatus 100 with reference to FIG.
Here, a case is shown in which the ion species is B +, the ion beam current is 0.2 mA, 30 keV, the ion source 110 is extracted, and the acceleration / deceleration tube 140 accelerates to 200 keV.
Since the space charge effect is effective inside the acceleration / deceleration tube 140 and the electrostatic scanner 160, the divergence of the beam B due to the space charge effect in this region is also considered in the simulation.

In FIG. 7, a curve EH above the central axis C represents the envelope of the ion beam B on the horizontal plane, and a lower curve EV represents the envelope of the ion beam B on the vertical plane.
The envelope of the ion beam B is a curve obtained by calculating the outer diameter of the ion beam B using the trajectory calculation of the ion beam B and continuously plotting the outer diameter.
In FIG. 7, the unit of the central axis C is m, and the vertical axis is mm.

Here, before the analysis of FIG. 7 is performed, the above-described space charge effect will be supplementarily described.
An ion beam is a system in which a group of particles having the same charge travels in the direction of the central axis designed.
Therefore, the Coulomb repulsive force acts on each ion in the ion beam, and in order to quantitatively analyze its exact motion, the Coulomb force acting between each particle must be considered. When becomes enormous, it becomes impossible to calculate all the Coulomb forces.

Therefore, if the ion beam is considered as a system in which space charges are continuously distributed, the motion of the ion beam can be calculated quantitatively by analyzing the electric field generated by the space charges.
In general, in the area where no electric field is applied, this space charge is a situation where electrons are trapped inside the ion beam by the positive potential of the ion beam itself, the space charge of the ion beam is neutralized, and the space charge effect does not work. become.
However, in the region where an electric field is applied like the acceleration / deceleration tube 140, electrons that neutralize the space charge of the ion beam flow out, and the ion beam is greatly diverged by the space charge effect, as will be described later. End up.

Incidentally, as is clear from the simulation shown in FIG. 7, the ion beam B immediately after passing through the mass separation slit 130 shows strong divergence in the horizontal plane, whereas the vertical plane is almost parallel. It is understood.
As shown in FIG. 7, when the ion beam current is 0.2 mA and the ion beam B energy is 200 keV, the outer diameter of the beam B on the substrate 180 is about 18 mm on the horizontal plane and about 26 mm on the vertical plane. .

Next, the second calculation result of the computer simulation based on the trajectory calculation program is analyzed for the trajectory of the ion beam in the conventional ion implantation apparatus 100 with reference to FIG.
Here, the ion beam is extracted from the ion source 110 at B +, the ion beam B current is 0.2 mA, and 30 keV. In contrast, the energy of B is decelerated to 10 keV.
As in FIG. 7, since the space charge effect is effective inside the acceleration / deceleration tube 140 and the electrostatic scanner 160, the divergence of the beam B due to the space charge effect in this region is also considered in the simulation.

Similarly to FIG. 7, in FIG. 8, a curve EH above the central axis C represents the envelope of the ion beam B on the horizontal plane, and the lower curve EV represents the envelope of the ion beam B on the vertical plane. .
As in FIG. 7, in FIG. 8, the unit of the central axis C is m, and the vertical axis is mm.

  As is apparent from FIG. 8, when the energy of the ion beam B is low, the beam B diverges due to the space charge effect, particularly while the vertical direction of the beam B travels from the quadrupole lens 150 to the substrate 180. It can be seen that the outer diameter of the beam on the substrate 180 exceeds 36 mm even at about 2 mA, and becomes as large as about 70 mm when converted to the diameter.

As a countermeasure, it is conceivable to reduce the outer diameter of the beam spot in the vertical direction of the ion beam B by the quadrupole lens 150.
However, in the configuration of the conventional ion implantation apparatus 100 shown in FIG. 6, the vertical plane of the beam B is already narrowed in the vicinity of the quadrupole lens 150 as shown in FIG. Even if the operating conditions are changed, it is difficult to suppress beam divergence due to the space charge effect from the quadrupole lens 150 to the substrate 180 with respect to the vertical plane.

  As described above, the convergence force of the quadrupole lens 150 is proportional to the distance from the center, but in the conventional ion implantation apparatus 100, the outer diameter of the ion beam B in the vicinity of the quadrupole lens 150. Is already small and cannot bring out a strong convergence effect.

On the other hand, the size of the beam B on the substrate 180 needs to be sufficiently smaller than that of the substrate 180 in order to inject the substrate 180 with good uniformity.
However, in the conventional ion implantation apparatus 100, in the case of low energy of about 10 keV, an ion beam having a large current of about 1 mA and a diameter of about 50 mm or less on the substrate 180 as clarified by the simulation of 0.2 mA. It is difficult to obtain B, and in the case of low energy, there is a problem that the beam B having a small spot size cannot be stably obtained with the large current ion beam B.

  The present invention solves the above-described conventional problems, adjusts the horizontal and vertical outer diameters of the ion beam, and can stably obtain an ion beam having a relatively small spot size even with low energy and large current. An object is to provide an apparatus.

In the ion implantation apparatus according to the first aspect of the present invention, ions are extracted from an ion source that generates ions, a desired ion species is selected by a mass separator, and the ion implantation apparatus is disposed downstream of the mass separator. The ion species transmitted through the mass separation slit is decelerated to a desired energy by a decelerating tube, and the ions are converged by a quadrupole lens disposed on the downstream side of the decelerating tube, so that an implantation surface of a substrate such as a semiconductor wafer is obtained. In the ion implantation apparatus for implanting desired ions, an adjustment electrostatic quadrupole lens for adjusting the outer diameter of the ion beam is disposed between the mass separation slit and the decelerating tube.

In the ion implantation apparatus according to claim 2, said mass separation slit between the adjusting electrostatic quadrupole lens, the mass electrons from the separation slit side to the adjusting electrostatic quadrupole lens is It was set as the structure which has arrange | positioned the electrode which applied the negative voltage which prevents flowing out.

In the ion implantation apparatus according to claim 3, said mass separation slit between the adjusting electrostatic quadrupole lens, the mass electrons from the separation slit side to the adjusting electrostatic quadrupole lens is It was set as the structure which has arrange | positioned the permanent magnet which prevents flowing out.

Since the ion implantation apparatus of the present invention is configured as described above, it has the following excellent effects.
(1) According to the first aspect of the present invention, the outer diameters of the horizontal and vertical surfaces of the beam can be made substantially equal in the vicinity of the quadrupole lens disposed on the downstream side of the speed reduction tube. The controllability of the beam from the multipole lens to the substrate is improved, and an ion beam with a relatively small spot size can be stably obtained with a large current even in the case of low energy where divergence due to the space charge effect is remarkable.
(2) Further, by making the adjustment quadrupole lens of an electrostatic type, the size can be reduced and the cost can be reduced.

(3) According to the second aspect of the present invention, it is possible to prevent a situation in which electrons flow out from the ion beam, and space charge neutralization is impaired and the beam diverges.

(4) When configured as described in claim 3 , similarly to claim 2, it is possible to prevent a situation in which electrons flow out from the ion beam and the neutralization of space charge is impaired and the beam diverges.

First to third embodiments of an ion implantation apparatus according to the present invention will be described sequentially with reference to FIGS.
First embodiment:
First, a first embodiment of an ion implantation apparatus of the present invention will be described with reference to FIGS. 6 to 8 using FIGS.

FIG. 1 is a plan view showing the main configuration of the first embodiment of the ion implantation apparatus of the present invention.
FIG. 2 is a diagram showing an envelope curve calculated by the trajectory calculation program for the trajectory of the ion beam in the ion implantation apparatus of the present embodiment, and shows a case where the ion beam has a low current.
FIG. 3 is a diagram showing an envelope curve calculated by the trajectory calculation program for the trajectory of the ion beam in the ion implantation apparatus of the present embodiment, and shows a case where the ion beam has a large current.

2 and 3, as in FIGS. 7 and 8, the curve EH above the central axis C indicates the envelope of the ion beam B on the horizontal plane, and the lower curve EV indicates the ion beam B on the vertical plane. Represents the envelope.
Similarly to FIGS. 7 and 8, the unit of the central axis C is m, and the vertical axis is mm.
In FIGS. 2 and 3, the mass separation slit 130 is not shown in order to avoid the complexity of the drawings.

First, the basic configuration of the ion implantation apparatus 10 of the present embodiment will be described.
As shown in FIG. 1, the structural feature of the ion implantation apparatus 10 of the present embodiment is that an ion beam is interposed between the mass separation slit 130 and the acceleration / deceleration tube 140 in the conventional ion implantation apparatus 100 of FIG. The adjustment electrostatic quadrupole lens 20 for adjusting the outer diameter of B is disposed.
Therefore, the other components are the same as those of the conventional ion implantation apparatus 100 shown in FIG. 6, and the description thereof will be omitted. Hereinafter, the adjustment static ion used for the ion implantation apparatus 10 of the present embodiment will be omitted. The operation of the electric quadrupole lens 20 will be mainly described.

  As described above, when the adjustment electrostatic quadrupole lens 20 is disposed between the mass separation slit 130 and the acceleration / deceleration tube 140, the convergence and diverging action of the ion beam B of the adjustment electrostatic quadrupole lens 20 is achieved. Thus, the outer diameter of the beam B in the vicinity of the quadrupole lens 150 (see FIG. 6) downstream of the ion beam B can be adjusted.

  The basic operational feature of the ion implantation apparatus 10 of the present embodiment is that, in the quadrupole lens 150, the convergence force of the ion beam B is proportional to the distance from the center and has a property that is stronger toward the outside. If the electrostatic quadrupole lens 20 is set so that the outer diameter of the downstream quadrupole lens 150 is increased, the strong convergence force of the downstream quadrupole lens 150 can be extracted.

FIGS. 2 and 3 show envelopes calculated using the trajectory calculation of the ion beam B in order to verify the above-described basic operational characteristics of the ion implantation apparatus 10 of the present embodiment.
FIG. 2 shows a case where the ion species is B +, the ion beam current is 0.2 mA, 30 keV, and the ion source is decelerated to 10 keV by an acceleration / deceleration tube.
This condition is the same as that in the conventional ion implantation apparatus 100 in which the beam diameter is expanded to about 70 mm.
FIG. 3 shows a case where the ion species is B +, the ion beam current is 1.0 mA, 30 keV, and the ion source is decelerated to 10 keV by an acceleration / deceleration tube.

  As shown in FIGS. 2 and 3, the ion beam B immediately after passing through the mass separation slit (not shown) diverges in the width direction (horizontal direction) of the slit, whereas in the longitudinal direction ( The vertical direction is parallel or convergent.

  Therefore, in the ion implantation apparatus 10 of the present embodiment, the adjustment electrostatic quadrupole lens 20 that adjusts the outer diameter of the ion beam B is disposed between the mass separation slit and the acceleration / deceleration tube 140 as described above. The adjusting electrostatic quadrupole lens 20 converges in the width direction and functions to diverge in the longitudinal direction, so that it is incident on the acceleration / deceleration tube 140 or in the vicinity of the downstream quadrupole lens 150. , The behavior of the beam B in the width direction and the longitudinal direction can be matched.

  As a result, even if acceleration / deceleration is performed by an acceleration / deceleration tube 140 having an axially symmetric structure that is easy to manufacture, the behavior of the beam B on two horizontal and vertical planes orthogonal to the optical axis C coincides, and acceleration / deceleration is achieved. In the vicinity of the quadrupole lens 150 arranged on the downstream side of the tube 140, the outer diameters of the horizontal and vertical surfaces of the beam B can be made substantially equal. As a result, the beam B from the quadrupole lens 150 to the substrate 180 can be made substantially equal. Even in the case of low energy where controllability is improved and divergence due to the space charge effect is remarkable, an ion beam having a relatively small spot size can be obtained stably with a large current.

Hereinafter, this will be quantitatively analyzed from FIG. 2 and FIG.
As apparent from FIGS. 2 and 3, the adjustment electrostatic quadrupole lens 20 increases the beam diameter of the downstream quadrupole lens 150, and the strong convergence force of the quadrupole lens 150 on the downstream side. Therefore, even when the ion beam B has a low energy, the beam B diverges due to the space charge effect while the diameter of the beam B proceeds from the quadrupole lens 150 to the substrate 180 in the vertical direction. It can be seen that the diameter of the beam B on the substrate 180 can be reduced to about 25 mm in the horizontal direction and about 30 mm in the vertical direction even with a large current of 1.0 mA.
Therefore, in the ion implantation apparatus 10 of the present embodiment, even when the ion beam B has a low energy and a large current, the ion beam B having a small spot diameter can be stably obtained, and sufficiently meets the demands of the latest technology. Is understood to be possible.

In the ion implantation apparatus 100 of the present embodiment, an electrostatic type is used as the adjustment quadrupole lens 20.
As a result, the size of the adjustment quadrupole lens 20 is reduced, and the size and cost can be reduced.

Second embodiment:
Next, a second embodiment of the ion implantation apparatus of the present invention will be described with reference to FIG.
FIG. 4 is a perspective view showing the main configuration of the second embodiment of the ion implantation apparatus of the present invention.

First, the main structure of the ion implantation apparatus 10B of this Embodiment is demonstrated using FIG.
A feature of the ion implantation apparatus 10B of the present embodiment is that, in the ion implantation apparatus 10 of the first embodiment shown in FIG. 1, between the mass separation slit 130 and the adjustment electrostatic quadrupole lens 20, This is the point that an electrode 30 to which a negative voltage is applied is arranged to prevent electrons from flowing out from the mass separation slit 130 side to the adjustment electrostatic quadrupole lens 20 side.
In this way, it is possible to prevent a situation in which electrons flow out from the ion beam B, the space charge neutralization is impaired, and the beam B diverges.

Third embodiment:
Next, a third embodiment of the ion implantation apparatus of the present invention will be described with reference to FIG.
FIG. 5 is a sectional view showing the main configuration of the third embodiment of the ion implantation apparatus of the present invention.

First, the main configuration of the ion implantation apparatus 10C of the present embodiment will be described with reference to FIG.
A feature of the ion implantation apparatus 10C of the present embodiment is that, in the ion implantation apparatus 10 of the first embodiment shown in FIG. 1, between the mass separation slit 130 and the adjustment electrostatic quadrupole lens 20, This is that a permanent magnet 40 for preventing electrons from flowing out from the mass separation slit 130 side to the adjustment electrostatic quadrupole lens 20 side is disposed.
In this way, as in the second embodiment, it is possible to prevent a situation in which electrons flow out of the ion beam B, and space charge neutralization is impaired and the beam B diverges.

The ion implantation apparatus of the present invention is not limited to the above embodiments, and various modifications can be made.
First, in the above embodiment, the adjustment quadrupole lens has been described as an electrostatic type. This is because the size can be reduced compared to the magnetic type, and the size can be reduced at a low cost. However, the magnetic type may of course be used.
In this case, the magnetic type itself has a function of preventing the outflow of electrons that impairs neutralization of the intermediate charge of the ion beam, so the electrodes and permanent magnets used in the second and third embodiments are It becomes unnecessary and the configuration becomes simple.

  Further, although the example of the ion implantation apparatus having the configuration shown in FIG. 6 has been described, it is not necessarily applicable only to this conventional example, and it goes without saying that the present invention can be applied to all apparatuses for implanting ions. .

It is a top view which shows the main structures of 1st Embodiment of the ion implantation apparatus of this invention. The figure which shows the envelope calculated by the orbit calculation program about the trajectory of the ion beam in the ion implantation apparatus of 1st Embodiment, and is a case where an ion beam is a low current. The figure which shows the envelope calculated by the orbit calculation program about the trajectory of the ion beam in the ion implantation apparatus of 1st Embodiment, and is a case where an ion beam is a heavy current. It is a perspective view which shows the main structures of 2nd Embodiment of the ion implantation apparatus of this invention. It is a top view which shows the main structures of 3rd Embodiment of the ion implantation apparatus of this invention. It is a top view which shows schematic structure of the conventional ion implantation apparatus. It is a figure which shows the envelope of the ion beam of the conventional ion implantation apparatus, and is a case where energy is high. It is a figure which shows the envelope of the ion beam of the conventional ion implantation apparatus, and is a case where energy is low.

Explanation of symbols

10, 10B, 10C, 100: ion implantation apparatus
20: Quadrupole lens for adjustment
30: Electrode
40: Permanent magnet
110: Ion source
120: Mass separator
130: Mass separation slit
140: Acceleration / deceleration speed tube
150: Quadrupole lens
180: Substrate
B: Ion beam

Claims (3)

Ions are extracted from the ion source that generates ions, the desired ion species are selected by the mass separator, and the ion species that have passed through the mass separation slit disposed downstream of the mass separator are converted to the desired energy by the speed reducer. In an ion implantation apparatus that decelerates and converges the ions by a quadrupole lens disposed on the downstream side of the deceleration tube, and implants the desired ions into an implantation surface of a substrate such as a semiconductor wafer,
An ion implantation apparatus, wherein an adjustment electrostatic quadrupole lens for adjusting an outer diameter of an ion beam is disposed between the mass separation slit and the decelerating tube. It said mass separation slit between the adjusting electrostatic quadrupole lens, to prevent from the mass separation slit side of electrons flowing into the adjustment electrostatic quadrupole lens, a negative voltage The ion implantation apparatus according to claim 1 , wherein an applied electrode is arranged. It said mass separation slit between the adjusting electrostatic quadrupole lens was disposed a permanent magnet to prevent from the mass separation slit side of electrons flowing into the adjustment electrostatic quadrupole lens The ion implantation apparatus according to claim 1 .

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