JPH06330314A - Method and apparatus for manufacturing functionally graded material by ion implantation - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method and an apparatus for manufacturing a functionally gradient material by an ion implantation method, which can strictly control the composition and structure and does not require a processing time. [Structure] Multivalent ion group generating means B is defined as an ion group having the same mass number and different valence number, different mass number and same valence number ion group, different mass number and different valence number ion group, or an ion group in which two or more of them are mixed.
And accelerate the ion group with the beam accelerating means D,
The object s to be processed is irradiated. Since this group of ions is a mixture of ions having different mass numbers and valences, they have different ion energies. Ion groups having different ion energies act on different depths because they have different ranges within the target object s. Therefore, the object s is modified so that the composition and the structure are different in the depth direction. [Effect] A functionally graded material can be obtained by a one-step process. The composition and structure of the surface layer of the object can be strictly controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a functionally gradient material by an ion implantation method, and more specifically, a method for producing a functionally gradient material by modifying the surface layer of an object to be processed by ion implantation. And equipment.

[0002]

2. Description of the Related Art A functionally graded material is a material whose composition and structure are changed in the depth direction from the surface of the material. This functionally graded material is expected to be able to achieve multiple functions such as mechanical strength properties, thermal properties, electrical properties, and chemical properties at a high level and at the same time, especially for applications in space equipment and aircraft fields. Has been actively researched.

FIG. 4 is a block diagram showing an example of an apparatus for producing a functionally gradient material by a conventional thermal spraying method. In the apparatus 400 for manufacturing a functionally graded material by this thermal spraying method, the decompression chamber 4
In the inside 1, the metal powder 44 and the ceramic powder 45 are simultaneously supplied into the plasma jet 43 generated from the plasma gun 42, and the mixed material of metal and ceramics is sprayed onto the substrate 46. Then, the metal powder 44 and the ceramic powder 4
The functionally gradient material is manufactured by controlling the composition ratio with respect to No. 5.

On the other hand, an ion implantation method is also used as a method of manufacturing a functionally graded material. As one example of a conventional method for producing a functionally gradient material by an ion implantation method, Japanese Patent Application Laid-Open No. Sho 60-1985
The technique described in Japanese Patent Publication No. 159168 is known. This is because the ions having the first ion energy are implanted into the object to be processed, the ions having the second ion energy are then injected, and the composition and structure are formed in the depth direction from the surface of the object in a two-step process. To produce a functionally gradient material.

[0005]

In the conventional apparatus for producing a functionally gradient material by the thermal spraying method described above, it is difficult to obtain a submicron thin film due to the nature of the thermal spraying method. There is a problem that cannot be controlled. Further, in the conventional method of manufacturing a functionally gradient material by the ion implantation method, since ions are implanted into the object to be processed in a two-step process, there is a problem that it takes a long processing time. Further, there is a problem in that the composition and the structure cannot be strictly controlled in the case of a material having a relaxation phenomenon (which changes with the passage of time) in the change of the composition and the structure due to ion implantation, such as a polymer material. Therefore, an object of the present invention is to provide a method and an apparatus for manufacturing a functionally gradient material by an ion implantation method, which can strictly control the composition and structure and does not require a processing time.

[0006]

According to a first aspect of the present invention, there is provided an equal mass number different valence ion group, a different mass number equal valence ion group, a different mass number different valence ion group or two of these. Provided is a method for producing a functionally graded material by an ion implantation method, which comprises producing an ion group in which species or more are mixed, accelerating the ion group, and irradiating a target object with ions to perform ion implantation.

In a second aspect, the present invention provides a multiply charged ion group generating means (B) for generating a multiply charged ion group in the plasma chamber (2) by utilizing electron cyclotron resonance, and the generated multiply charged ions. An extraction means (16) for extracting the group from the plasma chamber (2), a beam converging means (C) for converging the extracted ion beam by the multiply-charged ion group and suppressing the divergence of the ion beam, Beam accelerating means (D) for accelerating an ion beam by an ion group
And a beam irradiation means (E) for irradiating an ion beam of the multivalent ion group to ion-implant the object (s) to be processed (A). To do.

[0008]

In the method and apparatus for producing a functionally graded material by the ion implantation method of the present invention, an ion group of the same mass number and different valence number,
An ion group having a different mass number and the same valence number, a different mass number and a different valence number ion group, or an ion group in which two or more kinds of these are mixed is generated, the ion group is accelerated, and the object to be processed is irradiated. This group of ions is a mixture of ions having different mass numbers and valences, so that when they are accelerated, they have different ion energies. Ion groups having different ion energies act at different depths because they have different ranges in the object to be processed. Therefore, the composition and structure can be changed in the depth direction of the object to be processed. That is, a functionally graded material can be obtained by a one-step process.

[0009]

EXAMPLES The present invention will be described in more detail with reference to the examples shown in the drawings. The present invention is not limited to this. FIG. 1 is a configuration diagram of an embodiment of a functionally graded material manufacturing apparatus of the present invention. This functionally graded material manufacturing apparatus A includes a multiply-charged ion generator B, a beam focusing unit C, a beam accelerator D, and a beam irradiation unit E. The two-dot chain line indicates the track of the ion (beam).

FIG. 2 is a vertical sectional view of the multiply-charged ion generator B. The multiply-charged ion generator B is provided with a cylindrical plasma chamber 2 having both ends opened at the center thereof.
A sample gas and a microwave are supplied to the plasma chamber 2 from a gas introduction pipe g (see FIG. 1) and a waveguide m (see FIG. 1), which are arranged on the one open end side (the right side in the figure).
It is supposed to be introduced inside.

A permanent magnet 3 is provided on the outer periphery of the plasma chamber 2. The permanent magnet 3 is formed by arranging a plurality of sets of 6-pole permanent magnets in which six bar magnets are radially arranged in the radial direction of the plasma chamber 2 in the axial direction of the plasma chamber 2. A magnetic field is formed in the radial direction of the plasma chamber 2 by the permanent magnet 3.

A pair of solenoid coils 4 and 5 are arranged on both sides of the permanent magnet 3. These solenoid coils 4 and 5 are respectively held by iron yokes 6 and 7 which surround both inner and outer side surfaces and outer peripheral surfaces thereof.
The iron yokes 6 and 7 are completely separated.

The end faces on the plasma chamber side of the outer walls 6a, 7a and the inner walls 6b, 7b of the iron yokes 6, 7 are all parallel to the axis of the plasma chamber 2.
The end surfaces of the outer walls 6a and 7a on the plasma chamber side are arranged to have substantially the same diameter as the inner peripheral surfaces of the solenoid coils 4 and 5. Also, the outer walls 6a, 7
The end of a on the side of the plasma chamber is made to extend toward the side of the plasma chamber, and the area of the end face is increased. Thus, the iron yoke 6,7
Respectively hold the solenoid coils 4 and 5 individually, and are independently movable in the axial direction of the plasma chamber 2.

Insulators 10 and 11 are airtightly attached to both end faces of the plasma chamber 2 via O-rings 8 and 9, respectively. Further, iron yoke extension members 14 and 15 are airtightly attached to the outer end surfaces of the insulators 10 and 11 via O-rings 12 and 13, respectively.
The iron yoke extension members 14 and 15 are made of the same ferromagnetic material as the iron yokes 6 and 7, and the iron yoke extension member 14 on the inlet side of the plasma chamber 2, that is, the iron yoke extension member 14 on the right side in FIG.
It has a cylindrical shape extending in the axial direction of the plasma chamber 2. Further, the iron yoke extension member 15 on the outlet side of the plasma chamber 2, that is, on the left side in the figure, has a conical cylindrical shape that extends in the axial direction of the plasma chamber 2 and expands outward.

Thus, the iron yoke extension member 1 on the right side in the figure
4 to the iron yoke extension member 15 on the left side, a space that is airtightly shielded from the solenoid coils 4 and 5 side is formed, and the inside of the plasma chamber 2 is maintained in a vacuum state by vacuum suction of the space. It is designed to be drunk.

The iron yoke extension members 14, 15 are formed with a cylindrical outer peripheral surface parallel to the axis of the plasma chamber 2. The outer peripheral surface of the iron yokes 6 and 7 is brought into contact with the end surfaces of the outer walls 6a and 7a, whereby
In the meantime, they are magnetically connected.

The iron yoke extension member 15 on the outlet side of the plasma chamber 2 has a cathode 16 as an extraction electrode at its tip.
Is attached. The cathode 16 is arranged to project toward the central axis of the plasma chamber 2. On the other hand, an anode 17 is attached to the end of the plasma chamber 2 on the outlet side. Then, a high voltage of about 10 to 20 kV is applied between the anode 17 and the cathode 16, whereby the ions generated in the plasma chamber 2 are extracted to the outlet side.

Next, the operation of the multiply-charged ion generating section B will be described. A gas introduction pipe g and a waveguide m are hermetically connected to the iron yoke extension member 14 on the inlet side of the plasma chamber 2. Therefore, the inside of the plasma chamber 2 is vacuum-sucked by using the gas introduction pipe g, and the inside of the plasma chamber 2 is maintained at a high vacuum of about 10 ⁻⁷ Torr. Then, the sample gas and the microwave are introduced into the plasma chamber 2.
Then, the sample gas is excited by the microwave and becomes plasma.

At this time, a radial magnetic field is formed in the plasma chamber 2 by the permanent magnet 3. Also,
By energizing the solenoid coils 4 and 5, magnetic lines of force passing through the iron yokes 6 and 7 and exiting from the ends thereof are formed. Then, magnetic force lines 20 are formed from the end portions of the outer side walls 6a, 7a of the iron yokes 6, 7 through the iron yoke extension members 14, 15 magnetically connected thereto and connecting the extension members 14, 15 with each other. To be done. That is, an axial magnetic field is formed in the plasma chamber 2.

In this way, a synthetic magnetic field is formed in the plasma chamber 2 by superposing the radial magnetic field of the permanent magnet 3 and the axial magnetic field of the solenoid coils 4 and 5. Then, the synthetic magnetic field confines the plasma in the plasma chamber 2 except for the plasma that is directed substantially in the axial direction.

On the other hand, for the sample gas in the plasma chamber 2, the frequency of the microwave introduced into the plasma chamber 2 and the strength of the magnetic field formed in the plasma chamber 2 should be matched to predetermined conditions. Causes an electron cyclotron resonance. Therefore, the resonance accelerates the electrons in the plasma to become high-speed electrons. Then, when the high-speed electrons collide with the particles of the sample gas, the electrons around the particles are splashed. Thus, the particles of the sample gas are ionized. In that case, since the sample gas is confined in a plasma state, a large number of high-speed electrons collide with one particle. As a result, a plurality of electrons are splashed from one particle, and the particle becomes a multiply-charged ion. In this way, multiply charged ions are generated in the plasma chamber 2. For example, when O ₂ gas is introduced as a sample gas, O ⁺¹ ,
O ^{+ 2} , O ^{+ 3} , ..., O ^{+ 8} ,. Further, for example, when O ₂ gas and N ₂ gas are simultaneously introduced as sample gases, O ⁺² , O ⁺³ ,
..., O ⁺⁸ , ..., N ⁺² , N ⁺³ , ..., N ⁺¹⁰ , ..., and mass groups of different mass numbers and different charge numbers and multiply charged ions are generated. It

The generated multiply-charged ion group is attracted to the exit side of the plasma chamber 2 by the cathode 16 of the extraction electrode, and is extracted from the plasma chamber 2 as an axial ion group flow.

By the way, in the multiply-charged ion producing section B, the iron yoke extension members 14 and 15 are connected to the ends of the outer walls 6a and 7a of the iron yokes 6 and 7, and the outer walls 6a and 7a are
It is similar to the case where the end of 7a is extended inward. Therefore, the magnetic field lines formed by the solenoid coils 4 and 5 come out from the extension members 14 and 15. The distance between the extension members 14 and 15 and the ends of the inner side walls 6b and 7b of the iron yokes 6 and 7 is small. As a result, the magnetic field lines 21 and
2 will be formed.

Thus, in the vicinity of the end of the plasma chamber 2, the magnetic lines of force 20 connecting the pair of iron yoke extension members 14, 15 and the ends of the extension members 14, 15 and the inner side walls 6b, 7b of the iron yokes 6, 7 are formed. Magnetic field lines 21 and 22 connecting between the parts
Is formed. Therefore, the magnetic flux density in that portion is increased, and the magnetic field is strengthened. As a result, the maximum magnetic flux density in the mirror magnetic field is increased, and the confinement of plasma is improved. Further, since the magnetic field near the cathode 16 which is the extraction electrode is increased, it becomes possible to bring the plasma confinement region closer to the extraction electrode position.
The ion group generated in the plasma chamber 2 can be efficiently extracted, and a large-current ion beam can be obtained.

Further, in the multiply charged ion generating section B, the iron yoke 6, which holds the solenoid coils 4, 5, is held.
Since 7 is independent of each other, the spacing between the solenoid coils 4 and 5 can be changed by moving the iron yokes 6 and 7 in the axial direction. Then, when the magnetic flux density of the magnetic field formed by the solenoid coils 4 and 5 at a fixed position is as shown by the solid line in FIG. The density changes as shown by the one-dot chain line in FIG. 3, and the minimum value of the magnetic flux density in the central portion between the solenoid coils 4 and 5 becomes high. Further, if the distance between the solenoid coils 4 and 5 is increased, the minimum value of the magnetic flux density between them becomes low as shown by the broken line in FIG. On the other hand, the maximum value of the magnetic flux density hardly changes. The mirror ratio of the mirror magnetic field formed by the solenoid coils 4 and 5 is determined by the ratio between the maximum value and the minimum value of the magnetic flux density.

Therefore, the mirror ratio can be changed by adjusting the distance between the solenoid coils 4 and 5, and the optimization thereof can be achieved. Also, the positional relationship between the extraction electrode position and the electron cyclotron resonance region can be optimized. As a result, the multiply-charged ion generator B can efficiently obtain a large-current multiply-charged ion group.

The outer walls 6a, 7 of the iron yokes 6, 7 are
By extending the end portion of “a” inward and increasing the area of the end surface, the contact area with the iron yoke extension members 14, 15 is increased even when the iron yokes 6, 7 are moved in the axial direction. Although it is ensured that the iron yokes 6 and 7 are moved for adjusting the mirror ratio, the amount of movement of the iron yokes 6 and 7 is relatively small. Eliminating such an extension makes it easier to mount the solenoid coils 4, 5.

Returning to FIG. 1, the beam focusing unit C is provided with a plurality of stages of electrostatic lenses and focuses the ion beam extracted from the multiply charged ion generating unit B to suppress the divergence of the ion beam. To do.

The beam accelerating section D is, for example, a linear accelerator used for accelerating an electron beam, and accelerates the multiply-charged ion group by applying an accelerating voltage. For example, when an acceleration voltage of 100 kV is applied to accelerate a group of ions of O ⁺² , O ⁺³ , ..., O ^{+8 having} the same mass number, different valence numbers, and 100 kV, 200 kV
O ions having an ion energy (product of valence and acceleration voltage) of eV, ..., 800 keV are obtained.

The beam irradiation unit E includes a holder h for setting the object s to be processed at a desired position, a shutter t for controlling the irradiation time of the ion beam, and the like.

When the multiply charged ions having different ion energies as described above are simultaneously injected into the object s to be processed, the ions having large ion energy are deeply injected from the surface of the object s to be processed and the ions having small ion energy are injected. It is injected shallowly from the surface of the object s to be processed. Further, the number of such ions having high ion energy is different from the number of ions having low ion energy. Therefore, the composition and structure can be changed in the depth direction from the surface of the target object s. That is, the functionally gradient material can be obtained by one irradiation process.

Here, if the ion energy is adjusted by controlling the voltage of the beam accelerating portion D to change the implantation depth of the multiply-charged ion group, the composition and structure of the object s to be processed can be strictly controlled. You can control. That is, it is possible to obtain a high-quality functionally graded material. Similarly, if the ion energy is adjusted by controlling the amount of sample gas and the type of sample gas introduced into the plasma chamber to change the implantation depth of the multivalent ion group, the composition of the object s to be processed is And you can control the structure strictly. That is, it is possible to obtain a high-quality functionally graded material.

-Production Example 1-0.01 m / min from the gas introduction tube g of the multiply-charged ion producing section B
1 N ₂ gas and 14.25 GHz, 500 W microwave are introduced into the plasma chamber 2, 600 A is energized to the solenoid coils 4 and 5 to generate ECR plasma, and electrons are heated by ECR to generate plasma in the plasma chamber 2. To N ^{m +}
(A group of highly charged valences of nitrogen) was generated. The produced ratios of N ^{m +} are N ⁺¹ / 32 μA, N ⁺² / 39 μA, N ⁺³
/ 28 μA, N ⁺⁴ / 16 μA, N ⁺⁵ / 10 μA and N ⁺⁶ / 1.
It was 8 μA. 1 by extracting these multiply charged ions
The Al substrate was irradiated with an ion beam accelerated at 0 KV. The energy of each ion at this time is N ⁺¹ / 10ke
V, N ⁺² / 20keV, N ⁺³ / 30keV, N ⁺⁴ / 40
keV, which is N ⁺⁵ / 50keV and N + ⁶ / 60keV. After irradiation for 10 hours, about 20 nm from the surface of the Al substrate s
At the position of N: Al = 1: 1, as the depth becomes deeper, the ratio of N in the composition ratio N: Al decreases, about 15% from the surface.
A functionally gradient material having a composition ratio N: Al = 0: 1 at a position of 0 nm could be manufactured.

-Production Example 2-0.01 m / min from the gas introduction tube g of the multiply-charged ion producing section B
l N ₂ gas and 0.02 ml CH ₄ gas per minute,
A microwave of 14.25 GHz and 500 W was introduced into the plasma chamber 2 to generate 6 in the solenoid coils 4 and 5.
00A is energized to generate ECR plasma, and electrons are EC
By R-heating, N ^{m +} (a group of highly-charged ions having different valences of nitrogen) and C ^{n +} (a group of multiply-charged ions of carbon having different valences) were generated in the plasma chamber 2. The obtained N ^{m +} and C ^{n +} production ratio is
N ^{+ 1} / 30μA, N ⁺² / 35μA, N ⁺³ / 25μA, N ⁺⁴ / 15
μA, N ⁺⁵ / 8 μA, N ⁺⁶ /1.5 μA, C ⁺¹ / 32 μA, C
⁺² / 33μA, C ⁺³ / 23μA, C ⁺⁴ / 16μA and C ⁺⁵ /
It was 5 μA. 1 by extracting these multiply charged ions
The Ti substrate s was irradiated with an ion beam accelerated at 0 kV. The energy of each ion at this time is N ⁺¹ and C ⁺¹ / 1
0 keV, N ⁺² , C ⁺² / 20 keV, N ⁺³ , C ⁺³ / 30
keV, N ⁺⁴ , C ⁺⁴ / 40 keV, N ⁺⁵ , C ⁺⁵ / 50k
eV and N ⁺⁶ / 60 keV.

After irradiation for 10 hours, the composition ratio N: C: Ti = 1: 1: 1, at a position of about 20 nm from the surface of the Ti substrate s.
The composition ratio N: C: the ratio of N and C in Ti decreases as the depth increases, and the composition ratio N: C at the position about 120 nm from the surface is:
C: Ti = 0.5: 0: 1, and a functionally gradient material having a composition ratio N: C: Ti = 0: 0: 1 at a position of about 150 nm from the surface could be manufactured.

[0036]

According to the method and apparatus for producing a functionally graded material by the ion implantation method of the present invention, the group of ions having different ion energies are simultaneously irradiated to the object to be treated so that the composition and the structure are different in the depth direction. Then, the surface layer of the object is modified. Therefore, a functionally graded material can be manufactured by a one-step process. Further, the composition and structure of the surface layer of the object to be processed can be strictly controlled by controlling the valence and type of generated ions and the acceleration voltage.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of an embodiment of a functionally graded material manufacturing apparatus of the present invention.

FIG. 2 is a vertical cross-sectional view of a multiply-charged ion generator in the apparatus shown in FIG.

FIG. 3 is a graph showing changes in magnetic flux density when the distance between a pair of solenoid coils is changed in the multiply-charged ion generator of FIG.

FIG. 4 is a configuration diagram showing an example of a conventional apparatus for producing a functionally gradient material by a thermal spraying method.

[Explanation of symbols]

 A Manufacturing equipment for functionally graded materials B Multicharged ion generation part C Beam focusing part D Beam accelerating part E Beam irradiating part g Gas introduction tube m Waveguide s Object to be treated 2 Plasma chamber 3 Permanent magnet

Claims (5)

[Claims] 1. An ion group having the same mass number and different valence number ion group, different mass number and same valence number ion group, different mass number and different valence number ion group, or an ion group in which two or more kinds of these are mixed and generated. A method for producing a functionally graded material by an ion implantation method, which comprises accelerating a group, irradiating an object to be processed and performing ion implantation. 2. The method of manufacturing a functionally graded material by the ion implantation method according to claim 1, wherein the same accelerating voltage is applied to the ion groups having different valences so that different ion energies are introduced into the object to be processed. A method for producing a functionally graded material by an ion implantation method, which comprises: 3. The method of manufacturing a functionally graded material by the ion implantation method according to claim 2, wherein the ion energy applied to the ion group is controlled by controlling the acceleration voltage, and the object to be processed is modified by the ion implantation. A method for producing a functionally gradient material by an ion implantation method, characterized in that the composition and structure of the same are controlled. 4. A multicharged ion group generation means for generating multicharged ion groups in the plasma chamber by using electron cyclotron resonance, and an extraction means for drawing out the generated multicharged ion groups from the plasma chamber. Beam focusing means for focusing the ion beam by the highly charged ion group to suppress the divergence of the ion beam, beam accelerating means for accelerating the ion beam by the multiply charged ion group, and ion beam by the multiply charged ion group. An apparatus for producing a functionally-graded material, comprising: a beam irradiation unit that irradiates and ion-implants an object to be processed. 5. The apparatus for producing a functionally graded material according to claim 4, wherein the mass number and valence of the ion group are controlled by controlling the amount of sample gas and the type of sample gas introduced into the plasma chamber, An apparatus for producing a functionally gradient material, which is characterized by controlling the composition and structure of an object to be processed which is modified by ion implantation.