JP2006221941A - Ion implantation device and ion implantation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided an ion implantation device and an ion implantation method capable of ion implantation in a state that an oxide film is not formed on a silicon wafer surface. <P>SOLUTION: By enabling the irradiation of different type ion beams generated by first and second ion sources 11, 12, a process irradiating a silicon wafer 10 with a polyatomic molecule ion beam for removing a surface oxide film and a process irradiating the silicon wafer 10 with an ion beam of the implanted ions for implanting ions are continuously carried out to the silicon wafer 10 attached to a platen in a chamber 18 without breaking a vacuum atmosphere during them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ion implantation apparatus and an ion implantation method for transporting an ion beam into a substrate.

  In a manufacturing process of a semiconductor device such as a transistor, an impurity is doped into a semiconductor layer made of silicon or the like in order to form a source-drain region of the transistor. Conventionally, ion implantation apparatuses have been widely used to dope semiconductor layers with impurities.

  In the above ion implantation step, an oxide film as a sacrificial oxide film is formed on the surface of the semiconductor layer in order to suppress channeling and remove metal contamination and cross contamination when the semiconductor layer is irradiated with an ion beam. In general, ion implantation is performed.

  However, in the ion implantation process for forming a transistor, the following problems arise when the oxide film exists in the ion implantation of the extension portion using a low energy beam.

  First, when impurities are implanted (that is, ion implantation) in the presence of the oxide film, there is a problem in that implanted ions are taken into the oxide film and the actual implantation amount is reduced. In recent miniaturized transistors, the extension portion is formed with a layer thickness of 20 to 50 nm, whereas the oxide film is formed with a thickness of 5 to 10 nm. The ion implantation into the extension portion is performed in consideration of the amount absorbed by the oxide film. At this time, if the thickness of the oxide film is larger than the thickness of the extension portion, the amount of ions absorbed in the oxide film increases, and an accurate amount of ions can be implanted into the extension portion. It becomes difficult.

  Second, when the oxide film is a natural oxide film formed by combining with oxygen in the atmosphere, the thickness of the oxide film is not constant over time and has an in-plane distribution. There arise problems that the reproducibility of the amount is difficult and the distribution of implanted ions in the silicon wafer surface cannot be controlled to be constant.

  Due to the above problems, a method of removing the oxide film on the surface of the silicon wafer before ion implantation or a method of making the film thickness constant has been studied. For this purpose, the following two methods have been proposed.

  The first method is a method in which the thickness of the oxide film is made as thin and constant as possible by performing an oxide film etching of the silicon wafer immediately before the ion implantation step (predetermined time).

  In the second method, an oxide film etching (plasma etching or the like) of the silicon wafer is performed before the ion implantation process, and the silicon wafer is transferred from the oxide film etching chamber to the ion implantation chamber without being exposed to an oxidizing atmosphere. This is a method for suppressing the growth of an oxide film (for example, Patent Document 1).

  Here, a schematic configuration of a conventional ion implantation apparatus will be described below with reference to FIG. In this ion implantation apparatus, ions of impurities to be implanted are accelerated by an electric field, and the ions are implanted into a silicon wafer while scanning.

In the ion implantation apparatus shown in FIG. 4, ions of impurities to be implanted are generated in the ion source 101. At this time, since various types of ions are generated in the ion source 101, only necessary ions are separated in the separator (analysis magnet) 102. Ions separated by the separator 102 are taken into the scanner 104. Reference numeral 103 in FIG. 4 denotes an electric field applying means for applying a drawing electric field to the separated ions in the separator 102 and drawing the separated ions into the scanner 15. Ions that have passed through the scanner 104 are accelerated by an accelerator 105, further pass through a deflector 106, and are injected into a silicon wafer 110 in a chamber 107 that is an end station.
JP 2002-270535 A (published on September 20, 2002)

  However, the conventional configuration causes the following problems.

  First, in the first method, since ion implantation is performed in the presence of an oxide film, a dopant loss is unavoidable, and it is extremely difficult to make the loss amount uniform with good reproducibility.

  In the second method disclosed in Patent Document 1, an oxide film is etched in a first chamber (oxide film etching chamber), and ion implantation is performed in a second chamber (ion implantation chamber). The operation in this case will be specifically described as follows.

First, after etching the oxide film in the first chamber, the wafer is held in an inert gas atmosphere such as nitrogen or a vacuum atmosphere, and the wafer is transferred to the second chamber maintained at a low gas pressure. At this time, the pressure in the first chamber is usually 10 ⁻² to 10 ⁻¹ Pa, whereas the pressure in the second chamber is usually set to a pressure of 10 ⁻⁵ Pa, and then ion implantation is performed. For this reason, the transfer of the silicon wafer needs to be performed after the pressure in the first chamber is made equal to the pressure in the second chamber. In this way, the exhaust time to the vacuum in the first chamber becomes a loss time, It causes a decrease in throughput.

  Further, since it is formed in the presence of a very small amount of oxygen, it is extremely difficult to create a state where it is not exposed to an oxidizing atmosphere. For example, in order to etch an oxide film, etching is usually performed with a resist film attached. However, since the resist film contains hydrogen, carbon, and oxygen, the atmosphere during etching contains oxygen. It is an atmosphere, and an oxide film is formed on the silicon wafer.

  The present invention has been made in view of the above problems, and an object thereof is to realize an ion implantation apparatus and an ion implantation method that enable ion implantation in a state where an oxide film is not formed on the surface of a silicon wafer. There is to do.

  In order to solve the above-described problems, an ion implantation apparatus according to the present invention separates a plurality of ion sources and ions generated in each ion source in an ion implantation apparatus that transports an ion beam and implants it into a substrate. And separation means for selectively transporting the separated ions to the beam line.

  In the ion implantation apparatus, at least one of the plurality of ion sources generates ions of polyatomic molecules, and at least one of the plurality of ion sources generates ions to be implanted into the substrate. The substrate is irradiated with the ionized beam of polyatomic molecules to remove the oxide film on the substrate surface, and the substrate is irradiated with the ion beam of the implanted ions to implant ions into the substrate. It can be set as the structure which has.

  According to said structure, the said ion implantation apparatus is equipped with the several ion source and the isolation | separation means which isolate | separates the ion produced | generated in each ion source, and selectively carries out the beam line transport of the isolate | separated ion. Therefore, different types of ion beam irradiation processes can be performed in a continuous process on the same substrate attached to the platen.

  For example, a step of irradiating a substrate with an ion beam of polyatomic molecules to remove an oxide film on the surface of the substrate and a step of irradiating the substrate with an ion beam of implanted ions to implant ions into the substrate can be performed. In this case, the above two steps can be performed without breaking the vacuum atmosphere between them.

  For this reason, after removing the oxide film on the surface of the substrate, it is possible to continue ion implantation without forming an oxide film. Even when shallow ion implantation is performed on the substrate, the oxide film There is no absorption of ions at this point, and accurate ion implantation can be performed.

  Further, the ion implantation apparatus irradiates the substrate with an ionized beam of polyatomic molecules to form a thin film having a uniform thickness on the substrate surface, or irradiates the substrate with an ionized beam of polyatomic molecules. The substrate surface can have a function of amorphizing the substrate surface to a uniform thickness.

  According to the above configuration, a thin film such as an oxide film or an amorphous layer is formed on the substrate surface before ion implantation is performed on the substrate from which the oxide film on the surface has been removed. The effect of suppressing channeling during ion implantation can be obtained. The thin film such as an oxide film formed here can be formed sufficiently thinner than a conventional sacrificial oxide film or a natural oxide film, and accurate ion with minimal dopant loss in the oxide film. While injection can be performed, the effect of suppressing channeling is also obtained.

  In addition, when a thin film is formed on the substrate surface, it is possible to form an oxide protective film such as a nitride film on the substrate after the ion implantation. Thereby, after ion implantation, a natural oxide film is formed on the surface of the substrate conveyed to the atmosphere, and it is possible to suppress the occurrence of dopant loss due to the natural oxide film.

  In addition, the ion implantation apparatus includes a measurement unit that measures a beam current of ions that are not selected in the separation unit, and the measurement is performed while the substrate is being processed with the selected ion beam. Based on the beam current measured by the means, it can be configured to have a function of preparing for the beam startup of ions on the non-selected side.

  In the ion implantation apparatus, since it is necessary to frequently switch the ion species of the ion beam, it is preferable that the plurality of ion sources are operated at the same time. The current is measured by the measurement means, and the measurement result can be used to wait for the ion beam on the non-selection side for start-up and switching.

  Further, in the ion implantation apparatus, the separation means includes a shielding plate that prevents heavy ions or neutral particle beams generated from a certain ion source from entering another opposing ion source. be able to.

  In the ion source of the ion implantation apparatus, heavy ions and neutral particles are usually generated in addition to the desired ions. However, according to the above configuration, these heavy ions and Neutral particle beams can be prevented from entering other ion sources.

  In order to solve the above problems, an ion implantation method according to the present invention is an ion implantation method in which an ion beam is transported and implanted into a substrate. In the ion implantation method, the substrate is irradiated with an ionized beam of polyatomic molecules. An oxide film removing step for removing an oxide film on the surface of the substrate, and an ion for implanting ions into the substrate by irradiating the substrate from which the surface oxide film has been removed with an ion beam of implanted ions implanted into the substrate The oxide film removing step and the ion implantation step are performed without breaking the vacuum atmosphere between them.

  According to the above configuration, after removing the oxide film on the surface of the substrate, it is possible to continue ion implantation without forming an oxide film, and to perform shallow ion implantation on the substrate. However, there is no ion absorption in the oxide film, and accurate ion implantation can be performed.

  Further, in the ion implantation method, a thin film having a uniform thickness is formed on the substrate surface by irradiating the substrate with an ionized beam of polyatomic molecules after the oxide film removing step and before the ion implantation step. A structure having an amorphization step of irradiating the substrate with an ionized beam of polyatomic molecules and amorphizing the substrate surface to a uniform thickness can be obtained.

  According to the above configuration, a thin film such as an oxide film or an amorphous layer is formed on the substrate surface before ion implantation is performed on the substrate from which the oxide film on the surface has been removed. The effect of suppressing channeling during ion implantation can be obtained.

  Further, the ion implantation method includes an antioxidant film forming step of irradiating the substrate with an ionized beam of polyatomic molecules to form an antioxidant film on the substrate surface after the ion implantation step. be able to.

  According to said structure, a natural oxide film is formed in the board | substrate surface conveyed by air | atmosphere after ion implantation, and it can suppress that a dopant loss arises with this natural oxide film.

  In the ion implantation apparatus and the ion implantation method of the present invention, different types of ion beam irradiation processes can be performed in a continuous process on the same substrate attached to a platen. For this reason, the step of irradiating the substrate with the ion beam of polyatomic molecules to remove the oxide film on the surface of the substrate and the step of irradiating the substrate with the ion beam of implanted ions to implant ions into the substrate can be performed continuously. . In this case, the two steps can be performed without breaking the vacuum atmosphere between them.

  Thereby, after removing the oxide film on the surface of the substrate, it is possible to continue ion implantation without forming an oxide film. Even when shallow ion implantation is performed on the substrate, the oxide film There is no effect of ion absorption, and accurate ion implantation can be performed.

  An embodiment of the present invention will be described below with reference to FIGS. First, a semiconductor device manufacturing process including an ion implantation process according to the present invention will be described with reference to FIG. In the following description, a manufacturing process in the case where a MOS-FET transistor is formed on a silicon wafer will be exemplified.

  First, n well and p well are separated from the silicon wafer 10, and a sacrificial oxide film 21 is formed on the surface of the silicon wafer 10. Then, TW (Triple Well), DRW (Deep Retrograde Well), and Vth are implanted into the silicon wafer 10 from the side where the sacrificial oxide film 21 is formed. The DRW also functions as a CS (Channel Stopper). Also, STI (Shallow Trench Isolation) for isolating the transistor elements is formed. A state where the steps so far are completed is shown in FIG.

  Next, the sacrificial oxide film 21 is removed on the surface of the silicon wafer 10 to form a thermal oxide film 22. The state where the steps so far are completed is shown in FIG.

  Next, a polysilicon film is formed on the thermal oxide film 22 and etched to form the gate portion 23. The state where the steps so far are completed is shown in FIG.

  Next, side spacers 24 are formed on the side surfaces of the gate portion 23, and further, halo is implanted. Before the halo implantation, the silicon wafer 10 is transferred from the etching apparatus to the ion implantation apparatus (usually atmospheric transfer), so that the natural oxide film 25 is formed on the surface of the silicon wafer 10 at the time of halo implantation. The sacrificial oxide film 25 may be formed as a process. The state where the steps so far are completed is shown in FIG.

  Next, ion implantation into the extension portion 26 is performed on the silicon wafer 10. Here, when ion implantation is performed on the extension portion 26, if the oxide film 25 is formed on the surface of the silicon wafer 10, accurate ion implantation cannot be performed. Then, the oxide film 25 is removed. However, in the removal of the oxide film 25, the method of the present invention does not use a removal method that requires processing (plasma etching or the like) in an etching chamber as in the prior art (Patent Document 2). This is because, as described above, if the etching process in the etching chamber is performed in the removal of the oxide film 25, problems such as a decrease in throughput and generation of a natural oxide film during transfer occur.

  The method of the present invention is characterized in that the oxide film 25 on the surface of the silicon wafer 10 can be removed before the ion implantation into the extension portion 26 in a state where the silicon wafer 10 is mounted on the platen of the ion implantation apparatus. It is what you are doing. Specifically, the oxide film 25 is removed by irradiating the surface of the silicon wafer 10 with polyatomic molecular ions. In this method, the removal process of the oxide film 25 and the subsequent ion implantation process for the extension portion 26 can be performed continuously without breaking the vacuum atmosphere, and the above-described reduction in throughput and natural oxidation during transfer can be performed. Problems such as film formation can be solved. The state where the steps so far are completed is shown in FIG.

  Next, after a sidewall 27 is further formed on the side surface of the gate portion 23, ion implantation is performed on the source, drain, and gate portion of the transistor. Further, an annealing process for activating the implanted impurities and a silicidation process are performed, and finally a MOS-FET transistor as shown in FIG. 2F is obtained.

  Here, in the manufacturing process of the MOS-FET transistor, the manufacturing procedure from the creation of the gate portion to the creation of the sidewall is compared between the manufacturing process of the present invention and the conventional manufacturing process. As shown in a) and (b). FIG. 3A shows the manufacturing process of the present invention, and FIG. 3B shows the conventional manufacturing process.

  As can be seen from FIGS. 3A and 3B, the process from the creation of the gate portion to the halo implantation is the same as that of the present invention and the conventional process. However, after the Halo implantation is performed, in the conventional process, ions are implanted into the extension portion of the silicon wafer transferred to the atmosphere, whereas in the process of the present invention, the sacrifice / natural nature of the surface of the silicon wafer is performed. After the oxide film is removed (oxide film removal step), ion implantation into the extension portion (ion implantation step) is performed. Therefore, in the process of the present invention, in the ion implantation into the extension part, there is no ion absorption in the sacrificial / natural oxide film, and accurate ion implantation can be performed.

  As the polyatomic molecules used in the oxide film removal step, for example, any of rare gases or polymers made of fluorine, hydrogen, and compounds thereof can be used.

  Although not specifically described in the manufacturing process of FIG. 2, a protective nitride film may be formed on the surface of the silicon wafer after ion implantation into the extension portion. By forming such a protective nitride film, dopant loss after ion implantation can be suppressed.

  As described above, in the ion implantation method according to the present invention, in a state where the silicon wafer is mounted on the platen of the ion implantation apparatus, the oxide film is removed by irradiation with polyatomic molecular ions, and then the ions are implanted into the silicon wafer. Make an injection. Next, an ion implantation apparatus that enables such an ion implantation method will be described. FIG. 1 shows a schematic configuration of an ion implantation apparatus according to this embodiment.

  An ion implantation apparatus 1 shown in FIG. 1 includes a first ion source 11 for supplying ions of impurities to be implanted into a silicon wafer, and a first ion source for supplying polyatomic molecular ions for removing an oxide film. 2 ion sources 12. Only necessary ions are separated from the ions generated by the first ion source 11 or the second ion source 12 by the separator 13, and the separated ions are taken into the scanner 15. Reference numeral 14 in FIG. 1 denotes an electric field applying means for applying a drawing electric field to the separated ions in the separator 13 and drawing the separated ions into the scanner 15.

  Here, the separator 13 is configured so that the direction and intensity of the magnetic field generated therein can be switched, and the type of ions to be separated can be selected by switching the magnetic field. In FIG. 1, a case where impurity ions generated by the first ion source 11 are selectively separated is indicated by solid arrows, and a case where polyatomic molecular ions generated by the second ion source 12 are selectively separated. This is indicated by a dashed arrow.

  The separator 13 has a multi-Faraday cup 13A for measuring the beam current of non-selected ions on its side wall. In the ion implantation apparatus 1, since it is necessary to frequently switch ion species of the ion beam, the first and second ion sources 11 and 12 are preferably operated at the same time, and the beam current of the non-selected ions is selected. Can be measured by the multi-Faraday cup 13A, and using the measurement result, the ion beam on the non-selection side can be kept on standby for start-up and switching.

  The scanner 15 scans ions irradiated on the silicon wafer 10 by applying an electric field to the separated ions. The ions that have passed through the scanner 15 are accelerated by the accelerator 16 and have a predetermined energy. Further, the ions further pass through the deflector 17 to be separated from neutral molecules and injected into the silicon wafer 10 in the chamber 18 serving as an end station.

An example of a specific operation of ion implantation in the ion implantation apparatus 1 will be described below. In the ion implantation apparatus 1, for example, C ₆₀ carbon can be suitably used as the ion source material. In the second ion source 12, C ₆₀ powder is supplied to the ion source arc chamber using Ar gas as a carrier gas and ionized (C ₆₀ ⁺ ) in Ar plasma. C ₆₀ ⁺ ions are extracted as an ion beam (C ₆₀ ⁺ beam) with an extraction voltage of 4 keV.

If the mass separation capability of the analysis magnet 13A in the separator 13 is about 3000 AMU (Atomic Mass Unit) × keV, a 4 keV C ₆₀ ⁺ beam having a mass number of 720 AMU can be mass separated.

After the mass separation, when the silicon wafer 10 is irradiated with a C ₆₀ ⁺ beam accelerated to 60 keV by the accelerator 16, the oxide film on the surface of the silicon wafer can be removed by etching. At this time, the energy per C atom is about 1 keV, which is suitable for etching an oxide film. The end point of etching of the oxide film is detected by analyzing the residual gas during etching with a mass spectrum monitor.

When the etching end point is detected, the ion source gas is immediately replaced with BF ₃ gas. As described above, this is performed by switching the magnetic field of the separator 13. As a result, implantation with a dose of 2E14 / cm ² (ion implantation into the source-drain extension of the p-type MOS) is performed with a B beam energy of 0.5 keV and a beam current of 1 mA. In the case of an n-type MOS, an ion source gas may be AsH ₃ gas, and an As beam (a beam energy of 8 keV, a beam current of 1 mA, a dose of 2E14 / cm ² ) may be generated to perform ion implantation.

After ion implantation into the extension portion, in order to suppress the formation of an oxide film on the ion implantation surface of the silicon wafer 10, the silicon wafer 10 is held in an N ₂ atmosphere, and an Si nitride film is used as an antioxidant film. It can be formed to ensure the reproducibility of the wafer surface.

  In the above-described ion implantation method, the ion implantation into the extension portion is performed in a state where the oxide film on the wafer surface is removed before the ion implantation and no oxide film exists on the wafer surface. However, the oxide film on the wafer surface at the time of ion implantation has the merit of preventing channeling in addition to the above-mentioned disadvantage of dopant loss. I can't get it.

  For this reason, a silicon wafer from which the surface oxide film has been removed is irradiated with an ion beam of polyatomic molecules before ion implantation to form a thin film (such as an oxide film) having a uniform thickness ( The channeling prevention effect may be obtained by making the silicon wafer surface amorphous (amorphization process) or the like.

  In this case, the ion beam irradiation for forming the thin film and making the wafer surface amorphous can be performed using the same ion implantation apparatus. At this time, the ion beam for removing the oxide film and the ion beam for forming a thin film or amorphizing the wafer surface may be beams of the same ion species having different irradiation energies, and are different. It may be a beam of ion species. In the case of using beams of different ion species, the ion implantation apparatus may be configured to include three or more ion sources.

  In addition, as a polyatomic molecule used in the thin film forming step, for example, a polymer composed of fluorine, carbon, oxygen, hydrogen, and a compound thereof, or any of C60 and a carbon nanotube polymer can be used. It is.

  The polyatomic molecules used in the amorphization step include, for example, boron, fluorine, carbon, oxygen, hydrogen, a polymer composed of these compounds, or C60 or a carbon nanotube polymer. It is possible to use.

  Further, when an oxide film is formed as a thin film for preventing channeling, the oxide film can be formed to a desired thickness depending on the amount of ion irradiation, and a sacrificial oxide film or a natural oxide film that is removed first. The film thickness can be made sufficiently thin as compared with the above. For this reason, even when performing very shallow ion implantation as in the case of ion implantation into the extension portion, an effect of preventing channeling can be obtained while minimizing dopant loss.

In addition, when an anti-oxidation film is formed on the surface of the silicon wafer after ion implantation into the extension portion, the ion implantation is performed in addition to the natural formation of the anti-oxidation film (Si nitride film) by holding the silicon wafer in an N ₂ atmosphere. An antioxidant film may be formed (antioxidation film forming step) by irradiation of an ion beam of polyatomic molecules with an apparatus.

  In addition, as a polyatomic molecule used in the antioxidant film forming step, for example, a polymer made of fluorine, carbon, oxygen, hydrogen, and a compound thereof, or C60 or a carbon nanotube polymer is used. Is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, showing an embodiment of the present invention, is a block diagram showing a main part configuration of an ion implantation apparatus. 2A to 2F are cross-sectional views showing a manufacturing process of a MOS-FET transistor as a semiconductor device. FIG. 3A is a flowchart showing a part of the manufacturing process of the MOS-FET transistor according to the present invention, and FIG. 3B is a flowchart showing a part of the manufacturing process of the conventional MOS-FET transistor. It is. It is a block diagram which shows the principal part structure of the conventional ion implantation apparatus.

Explanation of symbols

1 Ion implanter 10 Silicon wafer (substrate)
11 First ion source (ion source)
12 Second ion source (ion source)
13 Separator (separation means)
13A Multi Faraday cup (measuring means)
25 Natural oxide film (oxide film)
26 Extension part

Claims (14)

In an ion implantation apparatus that transports an ion beam into a substrate,
A plurality of ion sources;
An ion implantation apparatus comprising: separation means for separating ions generated in each ion source and selectively transporting the separated ions to a beam line. At least one of the plurality of ion sources generates polyatomic molecule ions;
At least one other of the plurality of ion sources generates implanted ions that are implanted into the substrate;
A function of irradiating the substrate with an ionized beam of the above polyatomic molecules to remove the oxide film on the substrate surface;
The ion implantation apparatus according to claim 1, wherein the ion implantation apparatus has a function of irradiating the substrate with an ion beam of the implanted ions and implanting ions into the substrate.   The ion implantation apparatus according to claim 2, further comprising a function of irradiating the substrate with an ionized beam of polyatomic molecules to form a thin film having a uniform thickness on the surface of the substrate.   The ion implantation apparatus according to claim 2, further comprising a function of irradiating the substrate with an ionized beam of polyatomic molecules to make the substrate surface amorphous to a uniform thickness. Furthermore, it comprises a measuring means for measuring the beam current of ions that are not selected in the separating means,
While processing the substrate with the selected ion beam, it has a function to prepare for the beam startup of ions on the non-selected side based on the beam current measured by the measuring means. An ion implantation apparatus according to any one of claims 1 to 4, wherein:   Further, the separating means includes a shielding plate for preventing heavy ions or neutral particle beams generated from a certain ion source from entering an opposing other ion source. The ion implantation apparatus according to any one of 5. In an ion implantation method in which an ion beam is transported and implanted into a substrate,
Irradiating the substrate with an ionized beam of polyatomic molecules to remove an oxide film on the surface of the substrate; and
An ion implantation step of implanting ions into the substrate by irradiating the substrate from which the oxide film on the surface has been removed with an ion beam of implanted ions implanted into the substrate,
The ion implantation method, wherein the oxide film removing step and the ion implantation step are performed without breaking a vacuum atmosphere therebetween.   Furthermore, it has a thin film formation step of irradiating the substrate with an ionized beam of polyatomic molecules after the oxide film removal step and before the ion implantation step to form a thin film having a uniform thickness on the substrate surface. The ion implantation method according to claim 7, which is characterized by:   Furthermore, after the oxide film removing step and before the ion implantation step, the substrate surface is irradiated with an ionized beam of polyatomic molecules to amorphize the substrate surface to a uniform thickness. The ion implantation method according to claim 7.   Furthermore, after the said ion implantation process, it has an antioxidant film | membrane formation process which irradiates the ionized beam of a polyatomic molecule to a board | substrate, and forms an antioxidant film | membrane on the substrate surface. 10. The ion implantation method according to any one of 9 above.   11. The polyatomic molecule used in the oxide film removing step is any one of a rare gas and a polymer composed of fluorine, hydrogen, and a compound thereof. Ion implantation method.   9. The polyatomic molecule used in the thin film forming step is a polymer composed of fluorine, carbon, oxygen, hydrogen, and a compound thereof, or C60 or a carbon nanotube polymer. The ion implantation method described in 1.   The polyatomic molecule used in the amorphization step is a polymer made of boron, fluorine, carbon, oxygen, hydrogen, and a compound thereof, or C60 or a carbon nanotube polymer. The ion implantation method according to claim 9.   The polyatomic molecule used in the antioxidant film forming step is a polymer made of fluorine, carbon, oxygen, hydrogen, and a compound thereof, or C60 or a carbon nanotube polymer. Item 11. The ion implantation method according to Item 10.

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