JPH06116710A - Aln coated metallic member and its production - Google Patents

Abstract

PURPOSE:To form an AlN film practically free from peeling on the surface of a metal and to provide an AlN coated metallic member excellent in corrosion resistance. CONSTITUTION:This AlN coated metallic member is constituted by forming an AlN film, having a columnar structure and oriented to (100) or (110) plane, on the surface of a metallic member. Moreover, by regulating argon gas pressure to a value higher than 2X10<-3>Torr or regulating film forming velocity to <=1.0Angstrom /sec, a sputtered AlN film having a columnar structure and oriented to (100) or (110) plane can be formed on the surface of a metallic member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal member having an AlN coating formed on the surface of a metal member and having excellent corrosion resistance, and is useful as a device member such as a semiconductor process device which requires high reliability. .

[0002]

2. Description of the Related Art Aluminum nitride: AlN is a ceramic material having characteristics such as high thermal conductivity and excellent heat dissipation, high electrical insulation, and a coefficient of thermal expansion of approximately the same as single crystal silicon at room temperature to 200 ° C. Yes, high integration I
It is often used as a C substrate material. AlN is a chemically stable substance and has excellent corrosion resistance such that it is not corroded by inorganic acids such as hydrochloric acid, sulfuric acid and hydrofluoric acid, and molten GaAs.

There is an example in which a coating material for a metal material has been studied by paying attention to such characteristics of AlN, but in general, a ceramic material is not limited to AlN and a vapor phase coating film is apt to have point defects. There is a problem that the film peels off from the defect. Since the metal material is corroded when the coating film is peeled off, investigations have been made to reduce defects, but the present situation is that the production of a vapor-phase coating film of a ceramic material free of defects has not been achieved.

[0004]

The present invention has been made in view of the above circumstances, and has found a method for forming an AlN coating that is difficult to peel off on a metal surface, and provides an AlN-coated metal member having excellent corrosion resistance. The purpose is to do.

[0005]

According to the present invention, which has achieved the above object, an AlN-coated metal member has a columnar structure and (1
The first gist is that the AlN film oriented to the (00) or (110) plane is formed on the surface of the metal material, and the argon gas pressure is set to be higher than 2 × 10 ^-3 Torr, or
Or by setting the film formation rate to 1.0 Å / sec or more,
The gist of the second invention is a method for producing an AlN-coated metal member having an AlN sputtering film having a columnar structure and oriented on the (100) or (110) plane on the surface of a metal material.

[0006]

The present inventors have made various examinations on the sputtering conditions and the characteristics of the formed film of the AlN film, and as a result, argon: Ar
It was clarified that the gas pressure is closely related to the microstructure and orientation of the AlN coating, and that the microstructure and orientation of the AlN coating influence the strength of the coating and affect the suppression of peeling. The invention has been reached. The present invention will be described in detail below.

In the present invention, AlN formed on the metal surface
It is essential that the film has a columnar structure and is oriented in the (100) or (110) plane. In order to form an AlN film satisfying the above conditions, the Ar gas pressure in the sputtering method is preferably higher than 2 × 10 ⁻³ Torr. Also, when it is not possible to control with Ar gas pressure,
Even if the film forming rate of AlN is 1.0 Å / sec or more, an AlN film satisfying the above conditions can be obtained. From the experimental results of sputtering with ArN as the target and changing the Ar gas pressure, when the Ar gas pressure is 2 × 10 ⁻³ Torr or less, the generated AlN film has the (002) plane orientation and grows with a grain structure. I found out. Those with AlN film with (002) plane orientation are those with Al oriented on (100) or (110) plane.
It was also clarified that the strength is weaker and the corrosion resistance is inferior to the N film. It is considered that the excellent corrosion resistance of the AlN film oriented on the (100) or (110) plane is due to the following action.

First, consider the corrosion process. When the metal material is coated with the AlN film, the corrosive medium reaches the metal through defects such as pinholes, and the metal immediately below the defect and the vicinity of the metal-film interface begin to corrode. When the metal around the defect corrodes, the metal and the coating can no longer be said to be in close contact. The AlN film that is not in close contact with the metal is completely peeled off (with breakage) by breaking the part that is not in close contact with the metal. Corrosion of the metal further spreads, and peeling of the coating also spreads.

Considering the above process, it is impossible to prevent 100% formation of pinholes at the present time when a ceramic material such as AlN is sputtered. However, by increasing the strength of the AlN film itself,
It is possible to prevent the film part floating from the metal from being broken and removed. Since the strength of the AlN coating specified by the present invention is more than twice as high as that of the coating oriented on the (002) plane (see FIG. 5 to be described later), the coating is tough and is not easily broken, so that peeling is suppressed, As a result, it is considered that the corrosion resistance is greatly improved. The preferred Vickers hardness of the AlN coating is 1000 HV or higher. If the Vickers hardness is less than 1000 HV, the effect of suppressing the film peeling is not exhibited, and only an AlN-coated metal member having poor corrosion resistance can be obtained.

In the present invention, the AlN film was produced by the sputtering method, but if an AlN film having a columnar structure and oriented in the (100) or (110) plane can be obtained,
A CVD method or a reactive ion plating method can also be used. Further, it is also possible to provide a highly functional coated metal member by applying the above action to a coating material other than AlN. The metal material used as the base material is not particularly limited, but a metal having excellent affinity and adhesion with the AlN film is preferable. It is possible to further improve the corrosion resistance by providing at least one adhesion improving layer between the AlN film and the metal material.

[0011]

The present invention will be described in more detail with reference to the following examples, but the following examples do not limit the present invention.
All modifications and implementations that do not depart from the spirit of the description below are included in the technical scope of the present invention. Example An Al-Mg alloy shown in JIS 5245 was used as a metal material, and was cleaned after mirror polishing. RF manufactured by Nippon Vacuum Co., Ltd.
Using a (high frequency) magnetron sputtering apparatus, AlN was deposited by the following procedure. The film forming conditions are shown in Table 1. 1. Introduce the sample metal into the chamber and set the base pressure to 2 x
Pre-evacuate to 10 ^-6 Torr. 2. Ar gas is introduced into the chamber until a predetermined film forming pressure is reached. 3. Target [AlN manufactured by Furuuchi Chemical Co., Ltd .; Purity
99% or more; 4 inch φ] Pre-sputtering is performed for 5 minutes to clean the surface. 4. Film formation is performed for a predetermined time.

[0012]

[Table 1]

[Observation of Microstructure] The cross section of the obtained AlN film of each test material was observed with a scanning electron microscope. In Figure 1
A cross section of the AlN film having an Ar gas pressure of 1 × 10 ⁻² Torr is shown in FIG. 2 for 2 × 10 ⁻³ Torr and in FIG. 3 for 5 × 10 ⁻⁴ Torr. In FIG. 1, it can be confirmed that AlN grows in a columnar shape. In FIGS. 2 and 3, no clear columnar structure was observed. From the results of other gas pressures, it was found that an AlN film having a columnar structure was obtained at a gas pressure higher than 2 × 10 ⁻³ Torr.

[Orientation measurement] The AlN film of each test material was subjected to X-ray diffraction measurement to measure the orientation of the film. In Figure 4,
The X-ray diffraction patterns of the samples formed under Ar gas pressures of 5 × 10 ⁻⁴ , 1 × 10 ⁻³ , 2 × 10 ⁻³ , 5 × 10 ⁻³ , and 1 × 10 ⁻² Torr are shown. In the figure, Ti is the diffraction line from the Ti substrate used for the X-ray diffraction substrate. All the diffraction lines from the sample can be indexed with the same wurtzite structure as the bulk, and all the obtained AlN are considered to be a single layer. As is clear from FIG. 4, the orientation state of AlN is (002) oriented preferentially at Ar gas pressure lower than 2 × 10 ⁻³ Torr, and 5 × 10 ⁻³ , 1 × 10 ⁻² Torr. , (100) and (110) planes were oriented. At 2 × 10 ^-3 Torr, (00
Both 2) and (100) orientations were observed. The lattice constant and unit cell volume obtained from each diffraction line are Ar.
It tended to decrease with increasing gas pressure. Since the atomic weight of N is smaller than that of Al, it tends to be scattered when a film is formed at a high Ar gas pressure, and the probability that N will surely reach a metal substrate is lower than that of Al. Conceivable.

[Film hardness] Vickers hardness was determined from the indentation depth of an indentation when the indentation load was 3 gf with a hardness meter having a diamond indenter. The results are shown in FIG. 500-600 at Ar gas pressure below 2 × 10 ^-3 Torr
While only HV can be obtained, 5 × 10 ^-3 , 1 × 10 ^-2 Torr
In, the hardness of 1000-1500HV is obtained, and it is 2 × 10
^It can be seen that the film state is different at ^-3 Torr.

[Evaluation of Corrosion Resistance] To evaluate the anticorrosion property, Al is used.
An AlN film having a thickness of about 1 μm was formed on a —Mg alloy substrate. After immersing each sample in a non-degassed 5% NaCl aqueous solution for 5 minutes, -500 mV vs Ag / AgCl
The sample was fixed at the potential of 1 and the change with time of the anode current during the potentiostatic polarization was monitored. The sample area was 1 cm ² , and the temperature of the solution was 25 ° C. The results are shown in Fig. 6. Uncoated Al
In the Mg substrate and the ones in which the AlN film was formed with Ar gas pressures of 5 × 10 ⁻⁴ and 1 × 10 ⁻³ Torr, the anode current increased immediately after the immersion. With 2 × 10 ^-3 Torr, the anode current started flowing out after 10 minutes, but with 5 × 10 ^-3 and 1 × 10 ^-2 Torr, 30
It did not flow until about a minute and showed excellent anticorrosion properties.
When the coating film after the immersion test was observed with a scanning electron microscope (not shown), destruction and peeling of the coating, which seems to have originated from the pinholes, were observed in the sample having a low Ar gas pressure. In the case of a high Ar gas pressure, corrosion of the substrate immediately below the pinhole was observed, but the surrounding film was not peeled off.

[0017]

Since the AlN coating defined by the present invention has excellent strength, it was possible to provide a metal member having excellent corrosion resistance by forming this AlN coating on the metal surface. In addition, especially by the sputtering method, Al having a columnar structure and oriented in the (100) or (110) plane
When forming a N film, the Ar gas pressure should be 2 × 10 ^-3 Torr.
Since it has been clarified that it is effective to increase the film thickness or to set the film forming rate to 1.0 Å / sec or more, it becomes possible to reproducibly manufacture an AlN-coated metal member having excellent corrosion resistance.

[Brief description of drawings]

FIG. 1 Al deposited with Ar gas pressure of 1 × 10 ^-2 Torr
It is a drawing substitute photograph which observed the structure state of the cross section of N film | membrane by the scanning electron microscope.

FIG. 2 Al deposited with Ar gas pressure of 2 × 10 ⁻³ Torr
It is a drawing substitute photograph which observed the structure state of the cross section of N film | membrane by the scanning electron microscope.

FIG. 3 Al deposited with Ar gas pressure of 5 × 10 ⁻⁴ Torr
It is a drawing substitute photograph which observed the structure state of the cross section of N film | membrane by the scanning electron microscope.

FIG. 4 is a diagram showing an X-ray diffraction pattern of an AlN film formed by changing the Ar gas pressure.

FIG. 5 is a graph showing the relationship between the Vickers hardness of an AlN film and the Ar gas pressure.

FIG. 6 is an AlN-coated Al- film formed by changing the Ar gas pressure.
It is a graph which shows the time-dependent change of the anode current at the time of constant potential polarization of Mg alloy.

Claims (2)

[Claims] 1. A columnar structure and (100) or (11
(0) An AlN-coated metal member having a surface-oriented AlN film formed on the surface of a metal material. 2. Argon gas pressure is higher than 2 × 10 ⁻³ Torr or film formation rate is 1.0 Å / sec or more, and has a columnar structure and is oriented on the (100) or (110) plane. Did A
A method for producing an AlN-coated metal member, which comprises forming an IN sputtering film on the surface of the metal member.