JP4562485B2 - Ion implanter - Google Patents

Description

  The present invention relates to an ion implantation apparatus, and more particularly, to an ion implantation apparatus that includes a low-cost ion beam distribution measurement device and improves the throughput of ion implantation.

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 FIGS.
FIG. 9 is a plan view showing a schematic configuration of a conventional ion implantation apparatus.
FIG. 10 is a perspective view showing an external configuration of a beam distribution monitor used by a conventional ion implantation apparatus.

As shown in FIG. 9, 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 tube 140, a quadrupole lens 150, a scanner 160, a collimator 180, a Faraday. They are a current monitor 190 and a beam distribution monitor 200 of an ion beam such as a cup.
In the figure, reference numeral 170 denotes a substrate serving as a target for implanting ions arranged in an end station (not shown).
B is an ion, and may be referred to as an “ion beam” or “beam” hereinafter.

The ion source 110 is an apparatus that generates ions by stripping electrons from atoms and molecules.
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 a magnetic field or an electric field, and an ion species to be injected into the substrate 170. It is a device for specifying.

  The acceleration tube 140 is a device for accelerating or decelerating a desired ion species that has passed through the mass separation slit 130. As shown in FIG. An equal high voltage is applied to the electrodes, and the ion beam B is accelerated or decelerated to a desired implantation energy by the action of an electrostatic field.

  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 170 and uniformly implanted.

Hereinafter, a plane including the implantation surface of the substrate 170 into which a desired ion species is to be implanted is referred to as a “scanning surface”, and the “scanning direction” of the ion beam B is a direction in which the ion beam is deflected by the scanner 160. It shall be said.
Although FIG. 9 shows the scanner 160 that deflects the ion beam B in the horizontal direction, a scanner that deflects in the vertical direction may be used.

Further, as shown in FIG. 9, a Faraday cup 190 that is a general current monitor for the ion beam B is disposed downstream of the substrate 170, and a beam distribution monitor 200 is disposed downstream of the Faraday cup 190. Yes.
In FIG. 9, reference numerals 192 and 202 denote ammeters.

  A conventional beam distribution monitor 200 is described in Non-Patent Document 1, but as shown in FIG. 10, a plurality of small Faraday cups 204 are arranged in the beam scanning direction with a gap of a predetermined width. It has become.

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 of a predetermined ion species with a predetermined energy at a uniform density over the entire implantation surface of the ions B of the substrate 170, an energy of about 30 keV from the ion source 110, for example. The ion beam B extracted in step S is deflected by the mass separator 120, and only predetermined ion species are selected by the mass separation slit.

The selected ion beam B is accelerated or decelerated by the acceleration tube 140 to an energy of about 10 to 500 keV, and an external electric field having a period of about 1 kHz is applied to the scanner 160 to scan the scanning surface of the substrate 170.
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.

Further, as shown in FIG. 9, in order to adjust the beam spot shape of the ion beam B on the substrate 170, an adjusting device such as a quadrupole lens 150 is installed between the acceleration tube 140 and the scanner 160. There are many cases.
A collimator 180 for collimating the beam B may be installed on the downstream side of the scanner 160.
Therefore, although the quadrupole lens 150 and the collimator 180 are illustrated in FIG. 9, they are not necessarily essential components of the ion implantation apparatus 100.

  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 170 is By scanning the ion beam B, uniform ion implantation processing of a desired ion species can be easily performed.

JP-A-8-213339 T. Hisamune et al. Proceedings of Int. Conf. On Ion Implantation Technology, IEEE98EX144 (1999) 411- T. Kunibe et al. Proceedings of Int. Conf. On Ion Implantation Technology, IEEE98EX144 (1999) 424-

By the way, with the miniaturization of semiconductor devices, the requirements for the dose amount implanted into the substrate and the surface uniformity of the ion implantation apparatus are becoming stricter. Specifically, the dose distribution in the implantation surface of the substrate is required to have a uniform accuracy of 1% or less within the range of 3σ.
In addition, due to the operational efficiency of the ion implantation apparatus, it is naturally required to shorten the apparatus startup time and to improve the throughput from the relation of the ion implantation efficiency.

Therefore, hereinafter, an ion implantation method for obtaining a highly uniform dose surface uniformity in a conventional ion implantation apparatus will be described with reference to FIG.
When the ion beam B is scanned by the scanner 160, the path of the ion beam B from the scanner 160 to the substrate 170, for example, the collimator 180, differs depending on the scanning angle, and the beam optical properties are slightly different. The spot shape of the ion beam B on the substrate 170 is generally slightly different.

For this reason, if the waveform of the external electric field applied to the scanner 160 is a simple triangular wave and the ion beam B is scanned with this triangular wave, the in-plane uniformity of the dose amount on the substrate 170 may not be obtained. is there.
In order to correct this, the substrate 170 is removed from the beam line and irradiated onto the beam distribution monitor 200 before being injected into the substrate 170, and the beam distribution monitor 200 irradiates the beam dose within the scanning plane of the substrate 170. And the scanning waveform of the external electric field applied to the scanner 160 is adjusted so that the distribution is uniform.

For example, in a region where the ion beam dose distribution is 5% higher than the average, the external electric field applied to the scanner 160 is increased so that the scanning speed at the scanning angle corresponding to the region is 5% faster. Adjust the scanning waveform.
In some cases, the beam shape is adjusted by operating the quadrupole lens 150 or the like while irradiating the beam distribution monitor 200 without scanning the beam.

Next, problems of the beam distribution monitor 200 used in the conventional ion implantation apparatus 100 will be described with reference to FIG.
As described above, the mechanism for monitoring the distribution of the beam is essential in order to obtain surface uniformity of the dose amount with high accuracy on the implantation surface of the substrate 170.

However, in the beam distribution monitor 200 of the conventional ion implantation apparatus 100, it is necessary to use a number of Faraday cups 204 and to make a part of the Faraday cups 204 mechanically movable.
In general, when a large number of Faraday cups 204 are used, it is necessary to calibrate each measured value of each of the many Faraday cups 204 in order to correct individual differences between them. There is a problem that the error remains.

Further, if a part of the Faraday cup 204 is mechanically movable, a mechanism for preventing electrical noise is also necessary.
As described above, the conventional ion implantation apparatus 100 has a problem that an error is caused by using a large number of Faraday cups 204, a problem that the startup time of the ion implantation apparatus 100 is long for the calibration, and a machine There is a problem that it is necessary to take measures against electrical noise in a typical movable mechanism, and it becomes expensive.

  In addition, the ion beam density distribution often has a tail in the peripheral part, but if the tail part is greatly expanded, the range of scanning angles that must be scanned increases, resulting in a decrease in throughput, There is a problem that the implantation efficiency of ion implantation is deteriorated.

This problem will be described with reference to FIGS.
FIG. 11 is a diagram showing a case where the tail portion of the density distribution on the scanning surface of the substrate 170 of the ion beam B is narrow in the conventional ion implantation apparatus 100.
FIG. 12 is a diagram showing a case where the tail portion of the density distribution on the scanning surface of the substrate 170 of the ion beam B is wide in the conventional ion implantation apparatus 100.

By the way, in general, the ion density distribution in a plane orthogonal to the optical axis of the ion beam has a shape having a high central portion and a tail in the periphery as described in Non-Patent Document 2.
Therefore, in order to avoid that the tail portion of the density distribution hits the periphery of the substrate 170 and the dose of the peripheral portion becomes larger than the set value, as shown in FIGS. It is necessary to deflect by the scanner 160 until it comes out of the substrate 170 almost completely.

Therefore, as shown in FIG. 11, when the tail width of the ion beam density distribution is small, the scanning range for scanning the ion beam B may be small. On the other hand, as shown in FIG. When the tail width of the distribution is large, the scanning range for scanning the ion beam B becomes large.
When the scanning range of the ion beam B by the scanner 160 is increased, the amount of the ion beam that is not implanted into the implantation surface of the substrate 170 is increased, so that the ion implantation throughput is lowered and the implantation efficiency is deteriorated.
Therefore, it is necessary to remove the adverse effect caused by the tail portion of the density distribution of the ion beam.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide an ion implantation apparatus provided with a low-cost ion beam distribution measuring apparatus and having improved ion implantation throughput.

In the ion implantation apparatus according to the present invention, a desired ion species is extracted from an ion source that generates ions, accelerated or decelerated to a desired energy, and the ions are applied to a semiconductor wafer or the like by a scanner. In an ion implantation apparatus that scans and implants ions on an implantation surface of a substrate, the device is disposed downstream of the substrate and is disposed between the substrate and the current monitor, and a current monitor that measures a current value of an ion beam. The ion beam distribution measuring device includes a shielding plate that can move in the same direction as the scanning direction of the ion beam and has a single slit.

The ion implantation apparatus according to claim 2, wherein a desired ion species is extracted from an ion source that generates ions, accelerated or decelerated to a desired energy, and the ions are ionized on an implantation surface of a substrate such as a semiconductor wafer by a scanner. In the ion implantation apparatus that scans and implants, a current monitor that is disposed on the downstream side of the substrate and measures a current value of the ion beam, and is disposed between the substrate and the current monitor. The ion beam distribution measuring device includes a strip-shaped shielding plate that is movable in the same direction as the direction and has a predetermined width.

  4. The ion implantation apparatus according to claim 3, wherein the shielding plate disposed between the substrate and the current monitor is removable from the front surface of the ion beam current monitor. The configuration.

  The ion implantation apparatus according to claim 4, wherein in the ion beam distribution measuring apparatus, secondary electrons are incident on a current monitor of the ion beam downstream of a single slit formed in the shielding plate. It was configured to attach a permanent magnet to prevent.

  The ion implantation apparatus according to claim 5, wherein, in the ion beam distribution measurement apparatus, a beam current amount in a state where the shielding plate having the single slit is removed from a front surface of the current monitor of the ion beam; With the shielding plate having one slit in front of the current monitor of the ion beam, while moving the shielding plate in the ion beam scanning direction, the position of the slit of the shielding plate and the slit of the shielding plate And an electronic circuit or a computer for storing the current amount of the ion beam that has passed through.

  7. The ion implantation apparatus according to claim 6, wherein in the ion beam distribution measuring apparatus, a beam current amount in a state where the strip-shaped shielding plate is removed from a front surface of the ion beam current monitor, and the strip-shaped shielding. While the plate is in front of the ion beam current monitor, while moving the shielding plate in the ion beam scanning direction, the position of the shielding plate and the current amount of the ion beam shielded by the shielding plate are determined. The electronic circuit or the computer for storing is provided.

The ion implantation apparatus according to claim 7, wherein a desired ion species is extracted from an ion source that generates ions, accelerated or decelerated to a desired energy, and the ions are ionized on an implantation surface of a substrate such as a semiconductor wafer by a scanner. In the ion implantation apparatus that scans and implants, a beam shaping slit having a variable slit width is disposed upstream of the scanner so as to remove a tail portion of a density distribution on the scanning surface of the substrate of the ion beam. Configured.

  The ion implantation apparatus according to claim 8 is the ion implantation apparatus according to any one of claims 1 to 6, wherein a tail portion of a density distribution on a scanning surface of the substrate of the ion beam is disposed upstream of the scanner. A beam forming slit having a variable slit width is disposed.

  10. The ion implantation apparatus according to claim 9, wherein the ion beam is uniformly irradiated from the dose distribution on the scanning surface of the substrate of the ion beam measured by the ion beam distribution measuring apparatus in a state where the ion beam is scanned. Is provided with a control mechanism for adjusting the width of the beam shaping slit so that the value becomes equal to or greater than a predetermined value including the optimum value.

  The ion implantation apparatus according to claim 10 has a uniform irradiation efficiency of the ion beam from a density distribution on the scanning surface of the substrate of the ion beam measured by the ion beam distribution measurement apparatus in a state where the ion beam is not scanned. A control mechanism for adjusting the width of the beam shaping slit so as to be equal to or greater than a predetermined value including the optimum value is provided.

Since the ion implantation apparatus of the present invention is configured as described above, it has the following excellent effects.
(1) When configured as described in claim 1, it is possible to make a single current monitor, eliminating measurement errors due to individual differences compared to the conventional case, and eliminating the need for calibration of measured values. The start-up time of the ion implantation apparatus can be greatly shortened.
(2) In addition, since the movable part is not directly related to current measurement, there is no risk of electrical noise, and many current monitors are not used. Wiring to be attached to can be greatly reduced.

(3) When configured as described in claim 2, it is possible to make a single current monitor as in claim 1, and there is no measurement error due to individual differences compared to the conventional case, and the measured value This eliminates the need to calibrate the ion implantation apparatus and significantly shortens the startup time of the ion implantation apparatus.
(4) In addition, because the movable part is not directly related to current measurement, there is no risk of electrical noise generation, and many current monitors are not used. Wiring to be attached to can be greatly reduced.

(5) When configured as described in claim 3, the total amount of the ion beam current can be measured by removing the shielding plate from the front surface of the current monitor.

(6) With the configuration described in claim 4, it is possible to prevent the secondary electrons emitted from the side walls of the slits of the shielding plate from being incident on the current monitor by being irradiated with the ion beam.

(7) With the configuration described in claim 5, the distribution of the ion beam on the scanning surface of the substrate can be accurately measured and stored.

(8) When configured as described in claim 6, as in the case of claim 5, the distribution of the ion beam on the scanning surface of the substrate can be accurately measured and stored.

(9) According to the seventh aspect, the tail portion of the ion beam density distribution on the scanning surface of the substrate can be removed, and the scanning range of the ion beam can be narrowed, so that a reduction in throughput can be prevented. The ion implantation efficiency can be improved.

(10) According to the configuration described in claim 8, the distribution of the ion beam on the scanning surface of the substrate is measured, and the tail portion of the density distribution to be removed is calculated based on the measured value. Since the scanning range can be determined, the ion implantation efficiency can be further improved.

(11) According to the ninth aspect, the ion implantation efficiency can be quickly achieved by controlling the slit width of the beam shaping slit in accordance with the dose distribution of the ion beam on the scanning surface of the substrate. Can be improved.

(12) As in claim 10, by controlling the slit width of the beam shaping slit corresponding to the density distribution on the scanning surface of the substrate measured without scanning the ion beam, ions can be implanted quickly. Efficiency can be improved.

  First to fourth embodiments of an ion implantation apparatus according to the present invention will be sequentially described 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. 9 and 10 using FIGS.
FIG. 1 is an external perspective view showing a configuration of an ion beam distribution measuring apparatus 10 used in the first embodiment of the ion implantation apparatus of the present invention.
FIG. 2 is an external perspective view for explaining the basic operation of the ion beam distribution measuring apparatus 10 used in the first embodiment of the ion implantation apparatus of the present invention.

The ion implantation apparatus according to the present embodiment is characterized in that the ion beam distribution measurement apparatus 10 is attached to the downstream side of the substrate 170 in the conventional ion implantation apparatus 100 shown in FIG.
Accordingly, the upstream side of the substrate 170 has the same configuration as that of the conventional ion implantation apparatus 100, and the description thereof will be omitted. Hereinafter, the ion beam distribution measurement apparatus 10 used in the ion implantation apparatus of the present embodiment will be mainly described. explain.

First, the basic structure of the ion beam distribution measuring apparatus 10 used for the ion implantation apparatus of this Embodiment is demonstrated.
The ion beam distribution measuring apparatus 10 is arranged on the downstream side of the substrate 170 in the ion implantation apparatus (see FIG. 9), and a general Faraday cup 20 as a current monitor for measuring the current value of the ion beam B, and the substrate 170. A shielding plate 30 disposed between the Faraday cup 20 and a single slit 32, and a pair of permanent magnets 40A disposed downstream of the slit 32 formed in the shielding plate 30. 40B.
In FIGS. 1 and 2, reference numeral 22 denotes an ammeter of the Faraday cup 20.

The Faraday cup 20 has a sufficient width so that the amount of current of the ion beam can be measured when the ion beam is scanned on the scanning surface of the substrate 170 by the scanner 160 (see FIG. 9).
As shown in FIG. 1, the shielding plate 30 can be mechanically moved via a shielding plate holder 36 in the same direction as the scanning direction of the ion beam B.
The shielding plate holder 36 is rotatable about the shaft, and the shielding plate 30 can be removed from the front surface of the Faraday cup 20 by, for example, tilting it horizontally as shown in FIG.

  Although not shown, in the ion beam distribution measuring apparatus 10 used in the ion implantation apparatus of the present embodiment, the beam current amount in a state where the shielding plate 30 is removed from the front surface of the Faraday cup 20, and the shielding plate 30 are A computer that stores the position of the slit 32 of the shielding plate 30 and the amount of current of the ion beam that has passed through the slit 32 of the shielding plate 30 in the state of being in front of the Faraday cup 20 is provided.

When the ion beam distribution measuring apparatus 10 used in the ion implantation apparatus of the present embodiment is configured as described above, the slit of the shielding plate 30 is in a state where the shielding plate 30 is in front of the Faraday cup 20 as shown in FIG. The position of 32 and the amount of current of the ion beam transmitted through the slit of the shielding plate 30 at that position can be measured and stored in a computer.
In addition, as shown in FIG. 2, the total current amount of the entire ion beam is measured by tilting the shielding plate 30 horizontally and measuring the beam current amount with the shielding plate 30 removed from the front surface of the Faraday cup 20. can do.

Therefore, in the ion implantation apparatus of the present embodiment, unlike the conventional one, it is not necessary to use a large number of Faraday cups 204 for obtaining position resolution, so that the current monitor is a single Faraday cup 20. Compared to the conventional case, the measurement error due to individual differences is eliminated, calibration of the measurement value is unnecessary, and the start-up time can be greatly shortened.
Further, since the movable part is not directly related to the current measurement, there is no possibility that electrical noise is generated, and since many Faraday cups 204 are not used, the cost can be greatly reduced, and the Faraday cup 20 Wiring to be attached to can be greatly reduced (see FIG. 9).
Furthermore, by adjusting the width of the slit 32 formed in the shielding plate 30, the accuracy of the distribution of the ion beam to be measured can be raised to a desired class.

  Further, by arranging a pair of permanent magnets 40A and 40B on the downstream side of the slit 32 formed in the shielding plate 30, the ion beam B is irradiated so as to be secondary from the side wall or the like of the slit 32 of the shielding plate 30. Even when electrons are emitted, the electrons are trapped in the permanent magnets 40A and 40B, or the path is greatly bent, so that they can be prevented from entering the Faraday cup 20, and the reliability of the measurement data can be improved. improves.

Second embodiment:
Next, a second embodiment of the ion implantation apparatus of the present invention will be described with reference to FIG. 9 using FIG. 3 to FIG.
FIG. 3 is an external perspective view showing a configuration of an ion beam distribution measuring apparatus 10B used in the second embodiment of the ion implantation apparatus of the present invention.
4 and 5 are characteristic curves showing the relationship between the measured current amount of the ion beam distribution measuring apparatus 10B used in the second embodiment of the ion implantation apparatus of the present invention and the position of the shielding plate.

As in the first embodiment, the ion implantation apparatus according to the present embodiment is characterized in that the ion beam distribution measurement apparatus is provided downstream of the substrate 170 shown in FIG. 3 in the conventional ion implantation apparatus 100 shown in FIG. 10B is attached.
By the way, in the said 1st Embodiment, it demonstrated by the example using the shielding board 30 which has the single slit 32 in the ion beam distribution measuring apparatus 10. FIG.
On the other hand, in the ion beam distribution measuring apparatus 10B of the present embodiment, the ion beam distribution measuring apparatus 10B is disposed between the substrate 170 and the Faraday cup 20, and is movable in the same direction as the scanning direction of the ion beam B as shown in FIG. A strip-shaped shielding plate 50 having a predetermined width is used.

In this case, the total current amount of the entire beam can be measured by measuring the beam current amount with the strip-shaped shielding plate 50 removed from the front surface of the Faraday cup 20, and the total current amount of the beam is shown in FIG. , Indicated by a broken line T.
On the other hand, as shown in FIG. 3, the position of the shielding plate 50 and the ion beam incident on the Faraday cup 20 when the shielding plate 50 is moved in the scanning direction with the shielding plate 50 in front of the Faraday cup 20. The current amount of B can be measured, and this is indicated by a curve S in FIG.

The amount of current S when the shielding plate 50 is moved in the scanning direction in a state where the shielding plate 50 is in front of the Faraday cup 20 measures the amount of current of the remaining ion beam B not shielded by the shielding plate 50. It will be.
Therefore, as shown in FIG. 5, by subtracting the current amount S from the total current amount T, the position of the shielding plate 50 and the current amount of the ion beam B shielded by the shielding plate 50, that is, the position of the shielding plate 50. The ion beam distribution in the scanning plane of the substrate 170 can be measured.
Therefore, the ion beam distribution measuring apparatus 10B of the second embodiment can obtain the same effect as that of the first embodiment.

Third Embodiment Next, a third embodiment of the ion implantation apparatus of the present invention will be described with reference to FIGS.
FIG. 6 is a plan view of an essential part for explaining a third embodiment of the ion implantation apparatus of the present invention.
FIG. 7 is a schematic diagram showing the influence of the tail portion of the density distribution on the scanning surface of the substrate of the ion beam in order to explain the basic operation of the ion implantation apparatus of the present invention.
FIG. 8 is a schematic diagram showing a state in which the tail portion of the density distribution on the scanning surface of the substrate of the ion beam is removed in the ion implantation apparatus of the present invention.

As shown in FIG. 6, the ion implantation apparatus of the present embodiment has a density distribution on the scanning surface of the substrate 170 of the ion beam B on the upstream side of the scanner 160 in the conventional ion implantation apparatus 100 (see FIG. 9). It is characterized in that a beam forming slit 60 having a variable slit width capable of removing the tail portion is arranged.
In the present embodiment, the beam shaping slit 60 is shown as having a configuration arranged between the acceleration tube 140 and the quadrupole lens 150, but is not limited to this location.

As described above, for example, as shown in FIG. 7, when the spread of the tail portion in the density distribution of the scanning surface of the ion beam substrate 170 is large as described above, there is a problem that the throughput is lowered. When the tail portion is cut by adjusting the slit width of the forming slit 60 by the slit 60 as shown by the arrow in FIG. 6, the scanning range in which the beam is scanned by the scanner 160 as shown in FIG. Can be reduced.
That is, in the ion implantation apparatus of the present embodiment, by using the beam shaping slit 60, the adverse effect of the tail portion of the density distribution of the ion beam B is eliminated, so that the amount of the ion beam B that is scanned unnecessarily is reduced. This increases the throughput and improves the ion implantation efficiency.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG.
In the third embodiment, it has been described that the tail portion of the density distribution of the ion beam is removed by the beam shaping slit 60 and the throughput increases. However, the slit width of the beam shaping slit 60 is excessively narrowed, If the tail portion is cut too much, the scanning range by the scanner 160 is narrowed, but the total amount of ion beams passing through the shaping slit 60 is lowered, and conversely, the ion implantation efficiency may be lowered.

Therefore, the ion implantation apparatus according to the present embodiment includes the ion beam distribution measuring apparatus 10 shown in the first embodiment, the beam shaping slit 60, and a control mechanism that controls the slit width. did.
The characteristics of the ion beam distribution measuring apparatus 10 and the beam shaping slit 60 will not be described again because of the above-described relationship.

On the other hand, the control mechanism for controlling the slit width measures the dose distribution on the scanning surface of the substrate 170 by the ion beam distribution measuring apparatus 10 while the ion beam is scanned, and the tail portion is removed based on this distribution. By performing the gain calculation that the ion implantation amount is reduced due to the removal and the tail portion is removed and the scanning range scanned by the scanner 160 is narrowed to increase the implantation amount, uniform irradiation of the ion beam is performed. It has a function of adjusting the width of the beam forming slit 60 so that the efficiency is not less than a predetermined value including the optimum value.
Further, the density distribution on the scanning surface of the substrate 170 is measured by the ion beam distribution measuring apparatus 10 in a state where the ion beam is not scanned, and the ion implantation amount is reduced by removing the tail portion based on this distribution, and the tail The gain calculation may be performed to increase the injection amount by narrowing the scanning range scanned by the scanner 160 by removing the portion.

  With such a configuration, even if the parameters such as ion species to be implanted, implantation energy, beam quality, and operating conditions change variously, the optimum or suitable beam shaping can be performed quickly and the ion implantation efficiency can be improved. Can be improved.

The scanner of the ion implantation apparatus of the present invention is not limited to the above embodiments, and various modifications can be made.
First, the above embodiment has been described by using a general Faraday cup as an ion current monitor, but other current monitors may be used.
Further, although the example of the ion implantation apparatus having the configuration shown in FIG. 9 has been described, the present invention can be applied to all apparatuses for implanting ions into a substrate by scanning an ion beam using a scanner.
Furthermore, in the above-described embodiment, the example in which the shielding plate moves in the horizontal direction has been described. However, when the ion beam is scanned in the vertical direction, the shielding plate also moves in the vertical direction.

It is an external appearance perspective view which shows the structure of the ion beam distribution measuring apparatus used for 1st Embodiment of the ion implantation apparatus of this invention. It is an external appearance perspective view explaining the basic operation | movement of the ion beam distribution measuring apparatus used for 1st Embodiment of the ion implantation apparatus of this invention. It is an external appearance perspective view which shows the structure of the ion beam distribution measuring apparatus used for 2nd Embodiment of the ion implantation apparatus of this invention. It is a characteristic curve which shows the relationship between the measurement electric current amount of the ion beam distribution measuring apparatus used for 2nd Embodiment of the ion implantation apparatus of this invention, and the position of a shielding board. It is a characteristic curve which shows the relationship between the measurement electric current amount of the ion beam distribution measuring apparatus used for 2nd Embodiment of the ion implantation apparatus of this invention, and the position of a shielding board. It is a principal part top view explaining 3rd Embodiment of the ion implantation apparatus of this invention. In order to explain the basic operation of the ion implantation apparatus of the present invention, it is a schematic diagram showing the influence of the tail portion of the density distribution on the scanning surface of the substrate of the ion beam. In the ion implantation apparatus of this invention, it is a schematic diagram which shows the state which removed the tail part of the density distribution in the scanning surface of the board | substrate of an ion beam. It is a top view which shows schematic structure of the conventional ion implantation apparatus. It is a perspective view which shows the external appearance structure of the beam distribution monitor which the conventional ion implantation apparatus uses. In the conventional ion implantation apparatus, it is a schematic diagram showing a case where the tail portion of the density distribution on the scanning surface of the substrate of the ion beam is narrow. In the conventional ion implantation apparatus, it is a schematic diagram showing a case where the tail portion of the density distribution on the scanning surface of the substrate of the ion beam is wide.

Explanation of symbols

10: Ion beam distribution measuring device
20: Faraday cup (beam current monitor)
30: Shield plate
32: Slit 40A, 40B: Permanent magnet
60: Beam shaping slit 160: Scanner
B: Ion beam

Claims (10)

In an ion implantation apparatus that extracts a desired ion species from an ion source that generates ions, accelerates or decelerates to a desired energy, and scans and injects the ions onto an implantation surface of a substrate such as a semiconductor wafer by a scanner.
A current monitor disposed on the downstream side of the substrate and measuring a current value of an ion beam; disposed between the substrate and the current monitor; and movable in the same direction as the scanning direction of the ion beam; An ion implantation apparatus comprising an ion beam distribution measuring apparatus including a shielding plate having a single slit. In an ion implantation apparatus that extracts a desired ion species from an ion source that generates ions, accelerates or decelerates to a desired energy, and scans and injects the ions onto an implantation surface of a substrate such as a semiconductor wafer by a scanner.
A current monitor disposed on the downstream side of the substrate and measuring a current value of an ion beam; disposed between the substrate and the current monitor; and movable in the same direction as the scanning direction of the ion beam; An ion implantation apparatus comprising an ion beam distribution measuring apparatus including a strip-shaped shielding plate having a predetermined width. In the ion beam distribution measuring apparatus,
The ion implantation apparatus according to claim 1, wherein the shielding plate disposed between the substrate and the current monitor is removable from a front surface of the ion beam current monitor. In the ion beam distribution measuring apparatus,
Downstream of a single slit formed in the shielding plate, according to claim 1, characterized in that the secondary electrons to attach a permanent magnet to prevent from entering the current monitor of the ion beam Ion implanter. In the ion beam distribution measuring apparatus,
A beam current amount in a state where the shielding plate having the single slit is removed from the front surface of the ion beam current monitor;
With the shielding plate having the single slit in front of the ion beam current monitor, while moving the shielding plate in the ion beam scanning direction, the position of the slit of the shielding plate and the shielding plate ion implantation apparatus according to claim 1 or 4, the amount of current of the ion beam slit was transmitted and characterized by comprising an electronic circuit or computer stores. In the ion beam distribution measuring apparatus,
A beam current amount in a state in which the strip-shaped shielding plate is removed from the front surface of the ion beam current monitor;
While the strip-shaped shielding plate is in front of the current monitor of the ion beam, the position of the shielding plate and the ion beam shielded by the shielding plate while moving the shielding plate in the ion beam scanning direction. The ion implantation apparatus according to claim 2 , further comprising an electronic circuit or a computer for storing the current amount of the current. In an ion implantation apparatus that extracts a desired ion species from an ion source that generates ions, accelerates or decelerates to a desired energy, and scans and injects the ions onto an implantation surface of a substrate such as a semiconductor wafer by a scanner.
Upstream of the scanner, an ion implantation apparatus which is characterized in that so as to remove the tail of the density distribution in the scanning plane of the substrate of the ion beam, the slit width is disposed a variable beam shaping slit. 2. A beam forming slit having a variable slit width for removing a tail portion of a density distribution on a scanning surface of the substrate of the ion beam is disposed upstream of the scanner. 6. The ion implantation apparatus according to any one of 6 above. From the dose distribution on the scanning surface of the substrate of the ion beam measured by the ion beam distribution measuring apparatus in a state where the ion beam is scanned, the uniform irradiation efficiency of the ion beam becomes equal to or higher than a predetermined value including the optimum value. The ion implantation apparatus according to claim 8, further comprising a control mechanism that adjusts a width of the beam forming slit. From the density distribution on the scanning surface of the substrate of the ion beam measured by the ion beam distribution measuring apparatus in a state where the ion beam is not scanned, the uniform irradiation efficiency of the ion beam becomes equal to or higher than a predetermined value including an optimum value. The ion implantation apparatus according to claim 8, further comprising a control mechanism that adjusts a width of the beam shaping slit.

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