JPH0633456B2 - Method for producing aluminum material having crystalline aluminum nitride layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a semiconductor integrated circuit substrate, an application utilizing the electrical characteristics of an acoustic conversion device, a flange for high vacuum equipment,
The present invention relates to a method for producing an aluminum material having a crystalline aluminum nitride layer, which is suitable for applications using mechanical characteristics such as valves, and other applications utilizing various characteristics such as good thermal conductivity and corrosion resistance.

(Prior Art) In recent years, attempts have been made to develop various applications by utilizing the properties of aluminum nitride thin layer, which have various properties such as high thermal conductivity, electrical insulation, and wear resistance. There is.

For example, an aluminum nitride layer is formed on an aluminum substrate having excellent thermal conductivity, and its high thermal conductivity and electrical insulating properties are used to use it as a substrate for electronic materials and acoustic materials, as well as its wear resistance. In addition to sliding parts for general-purpose mechanical devices, new applications have been attempted for sliding parts such as flanges and valves of high vacuum equipment.

In order to form a thin aluminum nitride layer for these applications, reactive evaporation method and CVD method (Chemica
Vapor Deposition), sputtering method, ion plating method, etc.

(Problems to be Solved by the Invention) However, in the above-mentioned method, since the aluminum nitride thin layer is basically adhered to the aluminum surface in a coating state, peeling due to thermal cycle or mechanical impact is not caused. In addition, a thick film with a certain thickness or more (for example, 1 to 5 μm in the ion plating method) in order to satisfy desired characteristics.
There was a problem such as requiring. In addition, when used for electronic materials, it is desirable to use a crystalline aluminum nitride layer in view of its characteristics. However, in the above-mentioned manufacturing methods, a crystalline aluminum nitride layer is formed by a crystallization operation by heat treatment after forming a film. Therefore, there is a problem that the aluminum substrate itself is softened by heating and the film is peeled off as the manufacturing cost rises.

Recently, a method of forming an aluminum nitride layer on the surface of an aluminum material by an ion implantation method has been proposed, which is an excellent method in terms of adhesion of the aluminum nitride layer, but has a film thickness of 0.5 μm or more. However, it took about 4 hours to produce it, which was an industrial problem.

In order to solve this, a method of forming an aluminum nitride layer having excellent adhesion by applying a method such as ion sputtering and CVD after ion implantation as proposed in JP-A-60-128262 Although it has been tried, it was still unusable for practical use.

As a result of further studies by the present inventor, a crystalline aluminum nitride layer was formed by implanting nitrogen ions into the surface of an aluminum material under acceleration energy in a specific range, and then reactive ions of aluminum and nitrogen were formed. It has been found that crystalline aluminum nitride can be grown by performing a plating process.

The object of the present invention is a method for producing an aluminum material having a crystalline aluminum nitride layer which is a thin layer and has excellent adhesiveness and which has various characteristics such as electrical characteristics, mechanical characteristics and chemical stability equal to or higher than conventional ones. According to the present invention, the above aluminum material can be obtained in a short time and at low cost.

(Means for Solving the Problem) The present invention applies to aluminum materials an acceleration energy of 10 to 300.
Nitrogen is ion-implanted at a dose of 1 × 10 ¹⁸ ions / cm ² or more by KeV to form a crystalline aluminum nitride layer, and then an aluminum nitride crystal is formed on the crystalline aluminum nitride layer by a reactive ion plating method. A method for producing an aluminum material having a crystalline aluminum nitride layer characterized by obtaining a surface-modified layer consisting of a layer, whereby a crystalline aluminum nitride layer is formed by ion implantation with a film thickness of 500 to 1500Å. Since aluminum nitride is epitaxially grown on it by the reactive ion plating method, the aluminum nitride layer has a thickness of 0.
Even a thin layer having a thickness of 1 to 1 μm can exhibit desired characteristics.

In the present specification, the "aluminum material" means a thin film foil made of aluminum or aluminum alloy having a wall thickness of 50 μm or more, a plate material, a mold material, and those in which they are integrated with another base material, that is, a heat resistance of 200 ° C. or more. And materials that do not evaporate or degas at the degree of vacuum during ion implantation, such as other aluminum alloys, metal materials such as copper, inorganic materials such as glass and ceramics, insulating plastics such as epoxy resin and polyimide resin. It is a collective term for a substrate material such as a material and a thin film made of aluminum or aluminum alloy having a thickness of 5 μm or more, a foil, a plate, or the like.

The crystalline aluminum nitride layer is subjected to film removal treatment by a conventional method, for example, degreasing treatment with an organic solvent such as acetone or trichloroethylene, and then ion implantation while maintaining a vacuum degree of 2 × 10 ^{−6 to} 7 × 10 ⁻⁷ Torr. Nitrogen ions are implanted to the surface of an aluminum material at an acceleration energy of 10 to 300 KeV at a dose of 1 × 10 ¹⁸ ions / cm ² or more (as N ₂ ⁺ ) to form a 1500 Å thick layer.

In this case, the reason for setting the acceleration energy to 10 to 300 KeV is 3
Irradiation with nitrogen ions at an acceleration energy exceeding 00 KeV will cause irradiation damage to aluminum materials and generation of dislocations, which will adversely affect the coating and the substrate itself.On the other hand, if it is less than 10 KeV, a spattering effect will occur, which is appropriate. This is not desirable because it does not exhibit the effect of simple ion implantation.

In addition, when the required characteristics are high level such as electronic materials, it is more required to homogenize the crystalline aluminum nitride layer. In such a case, nitrogen ions with an acceleration energy of 10 to 200 KeV are preferable. By implanting, a desired crystalline aluminum nitride layer can be formed.

Further, by setting the implantation dose (N ₂ ⁺ ) of nitrogen ions to 1 × 10 ¹⁸ ions / cm ² or more, the Gaussian distribution in the film thickness direction of nitrogen ions in the generated crystalline aluminum nitride layer is eliminated. Since the nitrogen ion concentration can be made uniform, the adhesion to the reactive ion plating layer can be improved and the effect of the ion bombardment (discharge cleaning) on the characteristics can be minimized.

Incidentally, in maintaining the degree of vacuum in the ion implantation chamber as described above, by substituting the residual gas with nitrogen gas, it is possible to reduce the mixing of impurities by the ion implantation.

Then, the coating operation of the aluminum nitride layer by the reactive ion plating method is performed. At this time, when an ion plating apparatus separate from the ion implanter is used, it comes into contact with air after the ion implantation, so that the ion bombardment treatment is first performed and then the reactive ion plating treatment is performed. On the other hand, when using the same device that has both the ion implantation function and the ion plating function, the reactive ion plating process should be performed in the same device following the ion implantation by the function switching operation. Therefore, the ion bombardment process can be omitted.

In addition, the ion bombardment process is performed at a vacuum degree of 2 × 10 ^{-4 in the} room.
0.1-2. Using an aluminum material as a cathode in an atmosphere of argon gas or nitrogen gas maintained at ~ 7 × 10 ^-4 Torr.
10 ~ while applying high frequency of 100 ~ 400W with voltage of 0KV
By performing the treatment for 20 minutes, the oxides and the like on the surface of the aluminum material formed by contacting with air after ion implantation are discharged and cleaned.

In the reactive ion plating process, a crucible charged with aluminum having a purity of 99.99% or more is housed in the room, and the aluminum is heated and melted by an electron beam or the like, while the degree of vacuum in the room is 3 × 10 ^-4 ~. 7 × 10 ^-4 To
Hold the temperature at rr and evaporate the molten aluminum as a nitrogen gas atmosphere, while applying a voltage of -0.1 to -2.0 KV and a high frequency of 100 to 600 W to the surface of the aluminum material held at 20 to 300 ° C. To produce ionized aluminum nitride. At this time, ionized aluminum nitride is deposited on the crystalline aluminum nitride layer at a deposition rate of 0.6 to 2.0 Å / sec. As a result, in the case where the reactive ion plating method alone is used, the conventional methods 1 to 5 are used.
In the case of the present invention, various characteristics obtained when the film is formed to a thickness of about μm can be sufficiently exhibited with a film thickness of 0.1 to 1 μm. However, if desired, the thickness of the aluminum nitride layer can be set to 1 μm or more.

The reason why the thickness of the aluminum nitride layer is set to 0.1 μm or more is that if the thickness is less than 0.1 μm, the uniformity of the aluminum nitride layer due to the influence of the surface roughness of the first aluminum material and the stability of the characteristics are insufficient. Is. The film thickness is 2μ
If it is more than m, the improvement of various characteristics is not remarkable and it is disadvantageous in terms of cost.

Incidentally, in the present invention, by accelerating energy is 10 to 300 KeV, by implanting nitrogen ions, an aluminum nitride layer exhibiting crystallinity corresponding to it without destroying its base state depending on whether aluminum itself is single crystal or polycrystalline. It can be formed.

(Operation) The present invention forms a crystalline aluminum nitride layer on the surface layer portion of an aluminum material by setting the acceleration energy of nitrogen ion implantation into the aluminum material and the irradiation dose of implantation into a specific range, and then the reactive ion Depositing aluminum nitride thereon by plating produces an aluminum nitride crystal layer by epitaxial growth on the crystalline aluminum nitride layer formed by ion implantation. Therefore, according to the present invention, a crystalline aluminum nitride layer having a desired thickness can be obtained without an interface between the ion-implanted layer and the ion-plating layer. In comparison, the peeling resistance from the substrate is improved, and the characteristics of the aluminum nitride layer itself, such as the resistivity and the withstand voltage, are also improved. A thick aluminum nitride layer can be obtained.

(Effects of the Invention) The present invention is to perform reactive ion plating after performing nitrogen ion implantation on the surface of an aluminum material with specific acceleration energy as described above. (A) It is possible to obtain an aluminum nitride layer having an extremely thin film thickness and having desired characteristics in a crystalline form.

(B) The disadvantage of the ion implantation method that the manufacturing time is long is solved, and the manufacturing time can be shortened to less than half of the conventional manufacturing time, and the productivity can be remarkably improved.

(C) Cost reduction can be achieved by thinning.

And the like, and is extremely effective in industry.

(Examples) The present invention will be described in detail with reference to Examples, but the present invention is not limited thereto, and appropriate modes can be adopted as described above.

Example 1 An aluminum plate having a purity of 99.0% (plate thickness 0.1 mm) for an integrated circuit substrate was subjected to degreasing / film removal treatment and water washing treatment with a 50 g / l caustic soda aqueous solution to clean the surface.

Then, nitrogen ions (N ₂ ⁺ 60%, N ₊ 40%) were irradiated on the surface of the aluminum plate kept at room temperature with an acceleration energy of 90 KeV in an ion implantation chamber with a vacuum degree of 1 × 10 ^-5 Torr, and the ion implantation irradiation dose was increased. The ion implantation was terminated when the ion density reached 1 × 10 ¹⁸ ions / cm ² . (Ion implanter is Z-100 manufactured by ZYMET.
(Using a mold machine) Since it was taken out into the air after ion implantation, it was placed in a high frequency ion plating device and then the degree of vacuum was 5 × 10.
^-4 Aluminum plate in Ar gas atmosphere of Torr −
Ion bombardment was performed while applying a voltage of 1.0 KeV and a high frequency of 200W.

Then, while substituting a nitrogen gas atmosphere in the room, aluminum of 99.99% purity with a vacuum degree of 5.5 × 10 ⁻⁴ Torr is heated and melted by an electron beam to be evaporated, and then a voltage of −0.5 KV is applied to the aluminum plate. And a high frequency of 400 W was applied for ion plating treatment to form an aluminum nitride layer of 0.5 μm.

On the other hand, as a comparative material, the same aluminum plate was subjected to the same ion bombardment treatment and the same ion plating treatment without being subjected to nitrogen ion implantation treatment.

Table 1 shows the results of measuring the electrical characteristics of the products obtained above.

In addition, the results obtained by measuring the electric characteristics of current-voltage are
Shown in the figure. As is clear from FIG. 1, in Comparative Example (a),
The material of the present invention (b) showed a voltage of 28 V and a current of 0.45 μA, whereas it was broken at 1.5 V and a normal hysteresis curve could not be obtained, and showed good electrical characteristics.

Example 2 For a magnetic disk substrate, an aluminum-4% magnesium alloy plate (plate thickness 1 mm) surface-purified with a surface roughness Ra = 50Å was placed in an ion implantation chamber with a vacuum degree of 1 × 10 ⁻⁶ Torr. Nitrogen ions (N ₂ ⁺ ) were ion-implanted at an acceleration energy of 100 KeV to an ion implantation dose of 1 × 10 ¹⁸ ions / cm ² (the ion implanter is RIKEN 200KeVLow
Use Current Implonter).

Then, it was carried into a high frequency ion plating apparatus and subjected to ion bombardment by applying a voltage of -0.5 KeV and a high frequency of 400 W in an argon gas atmosphere having a vacuum degree of 5 x 10 ^-4 Torr.

After that, Al having a purity of 99.99% was evaporated as an aluminum ion source at a vacuum degree of 6 × 10 ⁻⁴ Torr and in a nitrogen gas atmosphere, and a substrate voltage of −0.5 KeV and a high frequency of 400 W were applied to the Al−.
Ion plating treatment by applying to Mg alloy plate 1
An aluminum nitride layer having a thickness of μm was formed.

On the other hand, as a comparative material, the same Al-Mg alloy plate was produced by performing only ion bombardment treatment and ion plating treatment under the same conditions.

When the dynamic insertion hardness was measured with an ultra-micro hardness tester (DUH-50 type measuring machine manufactured by Shimadzu Corporation) for the product obtained above, when the blank material not subjected to the above treatment was used as a reference, the present invention was obtained. The example showed an average hardness of 6 times, while the comparative example had an average hardness of about 2 times.

In addition, a sliding wear test was carried out at room temperature in the air at room temperature without lubrication using a pin-on-disk type abrasion tester using a sample as a disc and a pin as a mating material.
The amount of wear was measured under conditions of a Kgf and a wear rate of 100 mm / sec and a wear distance of 50 m. As a result, in the aluminum nitride layer with the same thickness produced by reactive ion plating, the one with nitrogen ion implantation reduced the wear amount to 1/5 compared to the one without implantation, and had good wear resistance. showed that.

Example 3 The same aluminum-4 wt% magnesium alloy as that used in Example 2 was subjected to nitrogen ion (N ₂ with an acceleration energy of 90 KeV using an ion implanter Z-100 manufactured by Zymet Co., Ltd.).
⁺ + N ₊ ) was implanted at a dose of 5 × 10 ¹⁷ ions / cm ² (line b in FIG. 2) and 1 × 10 ¹⁸ ions / cm ² (line c in FIG. 2).

Next, after setting the material to be processed in a high frequency ion plating apparatus, it is subjected to ion bombardment treatment and reactive ion plating of 99.99% pure aluminum and nitrogen gas applies a voltage of -0.5 KV and 400 W to the material to be processed. Ion plating treatment while applying high frequency, 1μm
Aluminum nitride layer was formed. As a comparative example, a 1 μm thick aluminum nitride film was formed only by reactive ion plating without nitrogen ion implantation (line a in FIG. 2).

Scratch test (using Swiss LSRH tester level test) for the sample manufactured above-Load-Acoust
When the ic emission characteristics were measured, the results shown in FIG. 2 were obtained.

According to this, the adhesiveness of the reactive ion plating layer of FIG. 2b and c of FIG. 2 improved after the ion implantation, compared with that of the non-implanted ion. ) Is the second ion implantation dose of 5 × 10 ¹⁷ ions / cm ² .
It can be seen that the adhesiveness is superior to that of the line shown in FIG. B, and the adhesiveness can be about twice as high as that of the non-ion-implanted one. This is a nitrogen ion implantation dose of 1 × 10
It is shown that ¹⁸ ions / cm ² or more is effective in improving the adhesiveness.

[Brief description of drawings]

FIG. 1 is a diagram showing the current-voltage characteristics of the substrate obtained in Example 1, and FIG. 2 is the load-Acoust obtained in the scratch test for the sample manufactured in Example 3.
It is a diagram showing an ic emission characteristic.

Front page continuation (72) Inventor Masaya Iwaki 2-1, Hirosawa, Wako-shi, Saitama, RIKEN (56) References JP-A-60-128262 (JP, A) JP-A-55-100974 (JP, A) ) JP-A-60-141869 (JP, A)

Claims (1)

[Claims] 1. An acceleration energy of 10 to 3 for an aluminum material.
Nitrogen is ion-implanted at a dose of 1 × 10 ¹⁸ ions / cm ² or more at 00 KeV to form a crystalline aluminum nitride layer, and then an aluminum nitride crystal is formed on the crystalline aluminum nitride layer by a reactive ion plating method. A method for producing an aluminum material having a crystalline aluminum nitride layer, which comprises obtaining a surface-modified layer consisting of layers.