JP4843252B2 - Surface treatment apparatus and surface treatment method - Google Patents

Description

  The present invention relates to a surface treatment apparatus for doping ions on a surface of a substrate to be processed installed in a vacuum chamber, and more specifically, ion doping using an ion beam and ion doping using a plasma doping method. The present invention relates to a composite-type surface treatment apparatus capable of performing the above and a surface treatment method used for the same.

  Conventionally, impurity ions are doped using an ion beam in order to form a doping region on the surface of a substrate to be processed such as a semiconductor wafer (see Patent Document 1 below). In particular, due to the recent increase in size of substrates and miniaturization of devices, shallow junctions of about several tens of nanometers are required. For this reason, the necessity of doping impurity ions such as B (boron) ions with low energy is increasing. .

  One method for doping ions into a semiconductor wafer with low energy is a plasma doping apparatus. The plasma doping apparatus includes a vacuum chamber for plasma formation, a plasma source for forming plasma, and a stage for supporting a substrate to be processed such as a semiconductor wafer, and ions in the plasma formed in the vacuum chamber are moved to the stage side. It is configured to be extracted and doped (see Patent Document 2 below).

  Conventionally, an ion implantation apparatus using an ion beam and a plasma doping apparatus are constituted by apparatuses independent from each other, and in the case of doping ions with high energy (for example, 2 keV or more), an ion implantation apparatus using an ion beam. In the case of doping ions with low energy (for example, 2 keV or less), a plasma doping apparatus has been used.

  On the other hand, in recent years, a surface treatment apparatus in which an ion implantation apparatus using an ion beam and a plasma doping apparatus are combined has been proposed (see Patent Document 3 below). This makes it possible to perform ion doping using an ion beam and ion doping using a plasma doping method with a single apparatus.

JP-A-11-345586 JP 2000-114198 A US Pat. No. 6,716,727

  As described above, in the field of semiconductor manufacturing technology in recent years, a shallow junction of about several tens of nanometers is required due to an increase in size of a substrate and miniaturization of a device, and it is necessary to dope a substrate with impurity ions with low energy. It is growing. For this reason, in recent years, research and development of ion doping treatment by plasma doping method has been actively conducted on the assumption that it is effective for ion doping with low energy.

Therefore, it is expected that in a complex surface treatment apparatus that combines an ion implantation apparatus using an ion beam and a plasma doping apparatus, the mainstream is processing using a plasma doping apparatus in low-energy ion doping processing. The
However, the plasma doping apparatus has a problem that it is difficult to ensure in-plane uniformity such as purity and dose of ions to be doped because the ion density of plasma to be formed is not uniform over the entire wafer surface. Yes.

  On the other hand, in an ion implantation apparatus using an ion beam, ions extracted from an ion source are mass-separated into desired ions, so that the purity of ions to be doped is high and excellent in-plane uniformity can be obtained. it can.

  Therefore, if low-energy ion doping treatment can be performed using an ion beam, the degree of freedom in device design, manufacturing process, etc. will be improved, and device characteristics evaluation when performed by plasma doping method and ion beam will be used. When trial verification with device characteristics evaluation is performed on a trial basis, the device can be prototyped with a single device, so it is highly accurate and reliable without being affected by the difference between devices. It is very useful in that it can perform excellent verification.

  However, the configuration of the composite surface treatment apparatus described in Patent Document 3 has a problem in that an ion doping treatment with a low energy (for example, 2 keV or less) using an ion beam cannot be performed with high accuracy and efficiency.

  That is, in order to perform low energy ion doping using an ion beam, it is necessary to decelerate the mass-separated ions on the beam transport path. At this time, the ion beam after passing through the decelerator has not only the target ion but also high-energy ions that have not reached the predetermined deceleration rate, that is, neutral ions generated by collision with residual gas in the beam transport path. Since the particles are contained, it is necessary to remove the neutral particles and irradiate the wafer with an ion beam consisting only of target ions.

  Further, in the ion doping process using an ion beam, the beam current decreases and the parallelism tends to be lost as the ion energy becomes lower. For this reason, the lower the energy, the lower the ion doping efficiency, which affects the processing speed and productivity. In the configuration described in Patent Document 3 described above, such a problem is not taken into consideration, so that the low energy ion doping process cannot be efficiently performed using the ion beam.

  The present invention has been made in view of the above-mentioned problems, and in a composite surface treatment apparatus that combines an ion implantation apparatus using an ion beam and a plasma doping apparatus, a low energy ion doping process can be performed with high accuracy using an ion beam. It is an object of the present invention to provide a surface treatment apparatus and a surface treatment method that can be performed efficiently.

  In solving the above problems, the present invention provides a surface treatment apparatus including an ion implantation unit and a plasma doping unit. The ion implantation unit includes a decelerator that decelerates ions and deflects decelerated ions to the stage side. And a bias means for guiding ions to the stage.

  With this configuration, the ion beam is irradiated onto the substrate to be processed with target ions from which neutral particles of high energy have been removed through the deceleration process by the speed reducer and the deflection process by the deflector. Can do. Thereby, high-precision ion doping treatment with low energy can be performed using the ion implantation unit.

  In addition, by applying a bias potential for introducing ions to the substrate to be processed as the bias means, it is possible to maintain a desired beam parallelism with suppressed ion beam divergence. A low energy ion doping process using an implantation unit can be performed efficiently.

  On the other hand, the plasma doping unit includes a container that is installed between the deflector and the stage and partitions a plasma forming space, and a plasma source that forms plasma. The substrate to be processed is supported on the stage so that its surface (processing surface) is close to the plasma formation space, and ions extracted from the plasma are doped onto the substrate.

  In the present invention, in the ion doping process by the ion implantation unit, the ion beam is processed through the inside of the container so that the ion doping process by the ion implantation unit can be performed at the same stage position as the plasma doping process. The substrate is irradiated. Thereby, size reduction of a vacuum chamber and reduction of the installation occupation area of an apparatus are achieved.

  In order to realize such a function, in the present invention, the container is composed of a container body that divides the periphery of the plasma formation space, and a top plate that opens and closes the upper part of the container body. In the doping process, the top plate waits at a position where the upper part of the container body is opened.

  As described above, according to the present invention, a low-energy ion doping process using an ion implantation unit can be performed with high purity and efficiency in a composite surface treatment apparatus having both an ion implantation unit and a plasma doping unit. Will be able to do.

  In addition, a device can be prototyped with a single device when trial verification is performed between the device characteristic evaluation performed by the plasma doping method and the device characteristic evaluation performed using an ion beam. . This makes it possible to perform highly accurate and reliable verification without being affected by the difference between devices.

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

  FIG.1 and FIG.2 is a schematic block diagram of the surface treatment apparatus 10 by embodiment of this invention.

  A surface treatment apparatus 10 according to the present embodiment includes a vacuum chamber 1 that is connected to an evacuation unit (not shown) and that can be maintained at a predetermined degree of vacuum, and a semiconductor as a substrate to be processed that is installed inside the vacuum chamber 1 A stage 4 for supporting a wafer (hereinafter referred to as “wafer”) W, and a plasma doping unit 21 and an ion implantation unit 31 for doping ions on the surface of the wafer W supported by the stage 4 are provided.

  First, the structure around the plasma doping unit 21 and the stage 4 will be described, and the surface treatment method (ion doping method) of the wafer W using the plasma doping unit 21 will be described.

  The plasma doping unit 21 includes, for example, a quartz bell jar (container) 11 that defines a plasma forming space P in the vacuum chamber 1, a gas introduction pipe 2 for introducing a plasma forming gas, and an outer periphery of the bell jar 11. And a high-frequency antenna (coil) 3 that is wound around the section and converts the plasma forming gas into plasma. The wafer W is supported by the stage 4 so as to be located immediately below the bell jar 11.

  The bell jar 11 includes a container main body 11A that partitions the periphery of the plasma forming space P, and a top plate 11B that closes the upper portion of the container main body 11. The top plate 11 </ b> B is openable and closable at the top of the container body 11 </ b> A by driving the top plate drive unit 40. The top plate 11B is in a position to close the container body 11A in the surface treatment process of the wafer W using the plasma doping unit 21 (FIG. 2), and in the surface treatment process of the wafer W using the ion implantation unit 31 described later. The container main body 11A is retracted to a position where the upper part is opened (FIG. 1).

  In the present embodiment, the mask member 5 is disposed to face the wafer W on the stage 4 with a predetermined gap. The mask member 5 is formed with a doping opening 5A that defines an ion introduction region for the wafer W.

  The stage 4 supports the wafer W with its processing surface directed toward the plasma formation space P (upper side in the figure). An electrostatic chuck mechanism is attached to the stage 4 as a support mechanism for the wafer W, and an X-direction (left-right direction in the figure) moving mechanism 6 and a Y-direction so that the stage 4 can be translated relative to the mask member 5. A moving mechanism 7 is attached (in the drawing, the front and back direction in the drawing). Reference numeral 8 denotes a tilt mechanism for tilting the wafer W on the stage 4, which is provided on the stage 4 and is adjusted as necessary. The stage 4 is provided with a rotation mechanism (not shown) so that the wafer W can be moved on the stage 4 in the rotation direction.

The mask member 5 and the stage 4 are connected to the negative electrode of the bias power source 9 so that ions (B ⁺ ions in this example) formed in the plasma forming space P can be extracted to the stage 4 side. The ions extracted from the plasma are doped on the surface of the wafer W through the doping opening 5 </ b> A of the mask member 5.

  The mask member 5 is made of, for example, a circular plate-like member made of semimetal that does not generate heavy metal contamination such as silicon, and the above-described doping opening 5A and a monitoring opening 5B to be described later are provided in the surface. Each is formed (FIGS. 3A and 3B). The shape, size, and the like of the doping opening 5A of the mask member 5 are not particularly limited, but are preferably formed corresponding to an arbitrary partial region of the plasma surface formed in the plasma formation space P.

  3A and 3B are plan views schematically showing the positional relationship between the mask member 5 and the wafer W. FIG.

  FIG. 3A shows an example in which the doping opening 5A is formed in a rectangular shape having a longitudinal dimension larger than the diameter of the wafer W. In this case, the stage 4 supporting the wafer W is configured to be movable intermittently or continuously only in a direction (X direction) orthogonal to the longitudinal direction of the doping opening 5A. Ion doping can be performed over the entire in-plane.

  FIG. 2B shows an example in which the doping opening 5A is formed in a rectangular shape having a size of a device unit (for example, one chip unit) on the wafer W. In this case, the stage 4 that supports the wafer W is configured to be movable intermittently or continuously in the X direction and the Y direction, so that ion doping can be performed over the entire surface of the wafer W.

  On the other hand, the monitor openings 5B of the mask member 5 are formed at one or a plurality of locations (two locations in the example of FIGS. 3A and 3B) adjacent to the doping aperture 5A. The formation position and the number of the monitor openings 5B are not particularly limited, and in this embodiment, a pair is formed so as to surround the doping opening 5A. The shapes and sizes of the monitor openings 5B and 5B are not particularly limited, and are not limited to the same shape and size. In the example of FIG. 3B, a pair of monitoring openings 5B may be provided not only in the X direction but also in the Y direction (four places in total).

  FIG. 4 is an enlarged view around the stage 4 that supports the wafer W. FIG. Between the wafer W on the stage 4 and the mask member 5, there is a main Faraday cup 12A for detecting the amount of ions passing through the doping opening 5A of the mask member 5, and ions passing through the monitoring openings 5B and 5B. Side Faraday cups 12B and 12B for detecting the amount are arranged. The side Faraday cups 12B and 12B correspond to the “detecting means” of the present invention.

  Here, the mask member 5 and the side Faraday cups 12B and 12B are disposed at positions facing the wafer W shown in the figure via a support frame (not shown) communicating with a stationary system such as the vacuum chamber 1. The support frame is provided with a drive mechanism similar to the tilt mechanism 8 and the rotation mechanism provided on the stage 4, and in synchronization with the tilt driving of the wafer W, the mask member 5 and the side Faraday cups 12B, 12B. Can be driven by tilting.

  On the other hand, the main Faraday cup 12A is attached to, for example, the support frame such that the main Faraday cup 12A can move back and forth between a position immediately below the doping opening 5A of the mask member 5 and a retracted position where the doping opening 5A is opened. Thus, the main Faraday cup 12A is configured to be detachable between the mask member 5 and the wafer W. During mass production, the dose amount of ions doped into the wafer W is monitored using the side Faraday cups 12B and 12B to ensure uniformity within the wafer W surface, reduce contamination, and improve the dose accuracy. Yes.

  Therefore, before mass production, the main Faraday cup 12A is disposed immediately below the mask member 5, and the amount of ions passing through the doping opening 5A is detected by the main Faraday cup 12A and also passes through the monitoring openings 5B and 5B. The area ratio of the amount of ions under mass production conditions is calculated in advance between the main Faraday cup 12A and the side Faraday cups 12B, 12B so that the amount of ions to be detected is detected by the side Faraday cups 12B, 12B.

  During mass production, the main Faraday cup 12A is retracted to the retracted position, and ions are detected on the side Faraday cups 12B and 12B while ions are introduced onto the wafer W through the doping opening 5A. By referring to the area ratio calculated in advance, the amount of ions passing through the doping opening 5A, that is, the dose amount of ions doped into the wafer W can be monitored. The dose amount can be adjusted by changing the plasma formation conditions.

  In the plasma doping process using the plasma doping unit 21 configured as described above, ions are extracted from the plasma formed in the plasma formation space P to the stage 4 side with an acceleration voltage corresponding to the power supply voltage of the bias power supply 9. Then, the ions are doped into the wafer W through the doping opening 5 </ b> A of the mask member 5.

  Therefore, even if the formed plasma is not uniform in the plane, the plasma region where the wafer W faces is limited by the doping opening 5A of the mask member 5, so that the stage 4 is moved in the X direction moving mechanism 6 and the Y direction. By horizontally moving with the mechanism 7, the entire surface of the wafer W can be uniformly doped with low contamination. Further, the accuracy of the dose amount of ions with respect to the wafer W can be improved by the ion irradiation amount detection mechanism using the side Faraday cups 12B and 12B. Furthermore, since ion implantation can be performed with low energy, it is possible to easily cope with shallow junction of the impurity region (diffusion region) to the surface of the wafer W.

  Next, the configuration of the ion implantation unit 31 will be described with reference to FIG.

  The ion implantation unit 31 includes an ion source 33, an extraction electrode 34 that extracts ions from the ion source 33, and a lens unit 35 that converges and forms a beam of ions extracted by the extraction electrode 34 and accelerated to a predetermined energy. Have. In the subsequent stage of the lens unit 35, a mass separator 36 for selecting desired ions, a decelerator 37 for decelerating the mass-separated ions to a predetermined energy, and deflecting the decelerated ions toward the stage 4 side. The deflector 38 is connected to each other. A beam line in the ion implantation unit 31 is formed in the beam transport path from the ion source 33 to the deflector 38.

  The extraction voltage of the extraction electrode 34 is preferably set so that the energy of ions passing through the beam line is in the range of 10 keV to 30 keV, for example. This is because if the energy of the ion beam L is smaller than 10 keV, the ion beam is likely to diverge and a loss of beam current is caused.

  The lens unit 35 is adjusted so that the ion beam is uniformly incident on the wafer W in the end station (vacuum chamber 1). The mass separator 36 is a mass separation magnet and selectively separates ions necessary for doping the wafer W.

  The speed reducer 37 can be formed of a speed reducing tube in which a plurality of ring-shaped electrodes are concentrically connected in series via a resistor. At this time, if the last electrode is set to the ground potential, the energy of the ions passing through the speed reducer 37 can be decelerated to the ground level. In this case, the energy of monovalent ions is 1 keV.

  The energy of ions decelerated by the decelerator 37 can be set in a range from 10 keV to several hundred eV, for example. If the ion energy is greater than 10 keV, the ion implantation depth becomes large, and it becomes difficult to form a shallow junction on the wafer W.

  The deflector 38 can be composed of an electrostatic deflection type deflector, and removes particles having an energy higher than 1 keV, for example. In this embodiment, the deflector 38 is arranged inside the vacuum chamber 1. However, if the inside of the deflector 38 communicates with the inside of the vacuum chamber 1, the deflector 38 is placed outside the vacuum chamber 1. You may arrange in.

  On the beam line, neutralized ions colliding with the residual gas have energy of 20 keV without being decelerated by the speed reducer 37, but the deflector 38 has only ions having energy of 1 keV. The applied voltage is adjusted so as to reach the wafer W on the stage 4 through the mask member 5. At this time, since the neutral particles travel straight without being deflected, they do not collide with the inner wall of the bell jar 11 or the upper surface of the mask member 5 and reach the wafer W.

  The ion beam deflected by the deflector 38 is irradiated onto the surface of the wafer W on the stage 4 through the inside of the bell jar 11. As described above, during the ion doping process using this ion beam, the top plate 11B of the bell jar 11 is retracted to a standby position (not shown) by driving the top plate driving unit 40, thereby the upper portion of the container body 11A. Is open (FIG. 1).

On the other hand, a bias power source 9 is connected to the stage 4 that supports the wafer W and the mask member 5 that is positioned immediately above the wafer W. Accordingly, ions emitted from the deflector 38 (for example, B ⁺ ions) are attracted to the wafer W with an extraction voltage corresponding to the power supply voltage of the bias power supply 9 and are doped into the region defined by the doping opening 5A of the mask member 5. Is done. Thereby, it becomes possible to irradiate the wafer W while suppressing the divergence of the ion beam emitted from the deflector 38, and it is possible to efficiently perform the low energy ion doping.

  In this example, the bias power source 9 and the stage 4 and the mask member 5 connected to the bias power source 9 constitute the “bias means” of the present invention. The bias power source 9 is not limited to a DC power source, and may be a pulse power source.

  Further, in the ion doping process using the ion implantation unit 31, the stage 4 is moved with respect to the mask member 5 by the X and Y direction moving mechanisms 6 and 7 in the same manner as the ion doping process using the plasma doping unit 21 described above. The ion beam is irradiated over the entire in-plane region of the wafer W. Thereby, in-plane uniformity can be ensured.

  In this embodiment, in order to improve the uniformity of the ion doping process, the deflector 38 is further provided with a scanning mechanism so that the ion beam is scanned in a minute angle range within the doping opening 5A of the mask member 5. . For example, as shown in FIG. 5, the scanning mechanism can be realized by superimposing triangular waves having opposite phases on a DC voltage applied to a pair of electrodes of the deflector 38.

  According to the present embodiment, in the composite surface treatment apparatus 10 that combines the ion implantation unit 31 and the plasma doping unit 21, low-energy ion doping treatment using the ion implantation unit 31 is performed with high purity and efficiency. It can be carried out. In addition, the low energy ion doping process can be performed by either the plasma doping unit 21 or the ion implantation unit 31.

  In addition, since the ion beam is irradiated onto the wafer W through the inside of the bell jar 11 during the ion doping process by the ion implantation unit 31, the ion doping process can be performed at the same stage position as the plasma doping process. As a result, the vacuum chamber 1 can be reduced in size and the installation area of the apparatus can be reduced.

  And in the surface treatment apparatus 10 of this Embodiment comprised as mentioned above, before starting mass production, it can be used when ion is experimentally doped to the wafer W and a characteristic is evaluated. . In this case, the characteristics evaluation of the device manufactured by the ion doping process using the plasma doping unit 21 and the verification of the characteristic evaluation of the device manufactured by the ion doping process using the ion implantation unit 31 should be performed with one apparatus. Can do. This makes it possible to perform highly accurate and reliable verification without being affected by the difference between devices.

  On the other hand, in the surface treatment apparatus 10 of the present embodiment, it is also possible to process one wafer W by using the plasma doping unit 21 and the ion implantation unit 31 in combination.

That is, the ion doping process using the ion implantation unit 31 is pure (high purity) because the doping ions are separated by mass. However, since the energy is low, the beam current is small and the processing time is longer than that of the plasma doping method.
Therefore, in performing the surface treatment of the wafer W, first, ion doping processing using the plasma doping unit 21 is performed (for example, 80 to 90% of the whole), and then high-purity ion doping processing is performed using the ion implantation unit 31. By doing so, the processing time can be shortened while maintaining the doping accuracy.

  Further, if the ion implantation energy of the ion implantation unit 31 is made larger than that of the plasma doping unit 21, the entire surface treatment apparatus 10 can have a wide implantation energy, and the energy from high energy to low energy can be increased. Energy continuity can also be obtained.

  The embodiment of the present invention has been described above. Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

  For example, in the above embodiment, an inductive coupling method (ICP) using the RF antenna 3 is used as the plasma source of the plasma doping unit 21. However, the present invention is not limited to this, and electron cyclotron resonance (ECR), parallel plate, magnetic Other types of plasma sources such as neutral wire discharge (NLD) are applicable.

  In addition, the shape and size of the bell jar 11 can be arbitrarily set. For example, the bell jar 11 may be configured to form plasma in accordance with the shape and size of the doping opening 5A of the mask member 5. Furthermore, if the inner surface of the bell jar 11 is coated with a film of the same material as the ions to be implanted, contamination during doping can be suppressed.

1 is a schematic configuration diagram of a surface treatment apparatus 10 according to an embodiment of the present invention. 3 is an enlarged view of a main part for explaining a plasma doping unit 21. FIG. 3 is a plan view showing a typical configuration example of a mask member 5. FIG. FIG. 4 is a partial cross-sectional side view for explaining the peripheral structure of the stage 4. 6 is a waveform diagram of an applied voltage for explaining an ion beam scanning operation by the deflector. FIG.

Explanation of symbols

1 Vacuum chamber 3 Antenna (plasma source)
4 Stage 5 Mask Member 5A Doping Opening 5B Monitor Opening 6, 7 X, Y Direction Movement Mechanism 9 Bias Power Supply 10 Surface Treatment Device 11 Belger (Container)
11A Container body 11B Top plate 12A, B Faraday cup 21 Plasma doping unit 31 Ion implantation unit 33 Ion source 34 Extraction electrode 35 Lens unit 36 Mass separator 37 Decelerator 38 Deflector 40 Top plate drive unit W Wafer (Processed substrate)

Claims (9)

Formed in the vicinity of the substrate to be processed, a stage installed in the vacuum chamber to support the substrate to be processed, an ion implantation unit for irradiating an ion beam onto the surface of the substrate to be processed and doping ions the pull the ions in the plasma to a surface treatment apparatus and a plasma doping unit for doping the surface of the substrate,
The ion implantation unit includes a decelerator that decelerates ions and a deflector that deflects decelerated ions to the stage side ,
The plasma doping unit includes a container installed between the deflector and the stage to partition the plasma formation space, a plasma source for forming the plasma, and bias means for guiding ions to the stage. A surface treatment apparatus comprising:   The surface treatment apparatus according to claim 1, wherein the ion implantation unit irradiates the substrate to be processed with an ion beam through the inside of the container.   The container includes a container body that divides the periphery of the plasma formation space, and a top plate that opens and closes an upper portion of the container body. The top plate is subjected to the ion doping process by the ion implantation unit. The surface treatment apparatus of Claim 2 which open | releases the upper part of a container main body.   In the vacuum chamber, a mask member disposed opposite to the substrate to be processed and formed with an opening for doping that defines an ion introduction region of the substrate to be processed, and at least one stage with respect to the mask member. The surface treatment apparatus according to claim 1, further comprising a stage drive mechanism that translates in a direction.   The mask member is provided with a monitor opening adjacent to the doping opening, and the amount of ions passing through the monitor opening is detected between the mask member and the substrate to be processed. The surface treatment apparatus according to claim 4, wherein detection means for performing the detection is disposed. A vacuum chamber, a stage installed in the vacuum chamber and supporting a substrate to be processed, an ion implantation unit for doping ions by irradiating the surface of the substrate to be processed, and an ion implantation unit are formed inside the vacuum chamber . Used in a surface treatment apparatus comprising a plasma doping unit for doping the surface of the substrate to be treated with ions in plasma;
The ion doping process by the ion implantation unit includes a step of decelerating ions and a step of deflecting the decelerated ions toward the substrate to be processed on the stage,
In the ion doping process by the ion implantation unit, the substrate to be processed is irradiated with an ion beam through the plasma formation space while a bias potential for guiding ions to the substrate to be processed is applied to the stage. Surface treatment method. Inside the vacuum chamber, a container that partitions the plasma formation space is installed as a part of the plasma doping unit,
The surface treatment method according to claim 6, wherein in the ion doping treatment by the ion implantation unit, the substrate to be treated is irradiated with an ion beam through the inside of the container. The container is composed of a container body that divides the periphery of the plasma formation space, and a top plate that opens and closes the upper part of the container body.
The surface treatment method according to claim 7, wherein the top plate opens an upper portion of the container main body in an ion doping treatment by the ion implantation unit.   The surface treatment method according to claim 6, wherein an ion doping treatment by the ion implantation unit and an ion doping treatment by the plasma doping unit are used in combination for the surface treatment of the substrate to be treated.

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