JPH0397210A - Film forming equipment and magnetic film using the same - Google Patents

Abstract

PURPOSE:To produce a film of high purity, high density, and low inner stress, by equipping the same vacuum vessel with an ion beam sputtering mechanism and an ECR plasma irradiating mechanism. CONSTITUTION:The title equipment is equipped with an ion gun 4, and performs the sputtering of a target 7 on a target holder 6, thereby sticking sputtered particle on a substrate on a substrate holder 10. An irradiating mechanism constituted of an ECR plasma generating part 5 and a gas introducing part 9 is installed so as to face the substrate, and performs the cleaning of the substrate, the plasma irradiation at the time of forming a film, etc. Ion beam sputtering method can obtain a film whose purity is high as compared with the case of high frequency sputtering method. A film formed by ECR plasma irradiation has little defect because of kinetic energy, and a film having high filling density can be obtained, so that a magnetic film of high purity, high density, and low inner stress can be produced.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a film forming apparatus, and more particularly to a film forming apparatus for producing a magnetic film with low internal stress.

[Conventional technology]

In recent years, magnetic recording technology has made remarkable progress, and recording density is being improved. In order to increase the recording density, it is necessary to use a recording medium with a high coercive force, and in order to magnetize a recording medium with a high coercive force, a magnetic pole material having a high saturation magnetic flux density is required. For this reason, in recording media, coated media coated with magnetic particles are being replaced by CO-based thin film media. In addition, in magnetic heads, Ni-Fe alloy (permalloy) and CO are used instead of conventional bulk materials such as ferrite.
Amorphous alloy thin films are beginning to be used as magnetic pole materials. Furthermore, magneto-optical recording media are also formed of thin films. For example, in addition to having a high saturation magnetic flux density, the magnetic head material is required to have high magnetic permeability in order to improve recording and reproducing efficiency. Furthermore, in order to prevent peeling and the like during the process of forming the magnetic head and maintain high magnetic permeability, it is required that the internal stress present in the magnetic film be small. As such a magnetic material, Japanese Patent Application Laid-Open No. 62-210607
6 and Institute of Electronics, Communication and Information Engineers MR88-55 (3
February 22nd), Fe, Go, Ni,
Metals selected from Mn include Nb, Zr, Ti, Ta, and Hf.
, Cr, W, Mo and nitrogen have been reported. The method for producing this material is to subject a metal target having a predetermined strength to high frequency sputtering using a mixed gas of argon and nitrogen as a sputtering gas. According to this report, by modulating the nitrogen concentration in the sputtering gas and alternately stacking nitrided and non-nitrided layers, a film with saturation magnetic flux density of 1.5T and coercive force of 10e or less can be obtained. There is. In addition, magnetic films with even higher saturation magnetic flux density include Fe, Fe-C, and Fe-N with a saturation magnetic flux density of around 2.0T.
There are materials such as, and these materials are mainly formed by ion beam sputtering method.

[Problem to be solved by the invention]

The present inventors sputtered Fe--Nb-based material in a mixed gas of argon and nitrogen, and conducted a follow-up experiment to the above-mentioned report. As a result, as reported, the coercive force can be increased to 1 by heat-treating the obtained film at 400 to 600°C.
It was confirmed that the value was as low as 00 or less. However, in this experiment, the present inventors found that the corrosion resistance of the obtained magnetic film was not necessarily sufficient, and that this was caused by impurities mixed into the magnetic film. In addition, the reason for the contamination of impurities is that the degree of vacuum during film formation was low and the film was formed in the presence of residual gas, and that plasma was generated in the film forming container and sputtered the inner wall of the container. It was assumed that. Additionally, in this experiment, it was necessary to introduce nitrogen gas intermittently during sputtering, but it was complicated to introduce nitrogen gas intermittently while maintaining a constant sputtering gas pressure. On the other hand, it was observed that a large compressive stress was applied to the magnetic film formed by ion beam sputtering.
The film often peeled off during the process of forming the magnetic head. This was expected to be caused by ions being implanted into the film by sputtering gas when the film was formed by ion beam sputtering. Furthermore, it has been confirmed that when the amount of sputtering gas mixed in increases, the filling density of the film decreases, and therefore the saturation magnetic flux density of the magnetic film decreases. Therefore, it is an object of the present invention to provide a novel film forming apparatus that eliminates the drawbacks of the above-mentioned conventional techniques, and in particular, to provide a film forming apparatus that can produce films of high purity, high density, and low internal stress. . Another object of the present invention is to provide a magnetic film of high purity, high density, and low internal stress produced using this apparatus. [Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors have continued intensive research, but the ion beam sputtering mechanism and E
We have discovered that a magnetic film with high purity, high density, and low internal stress can be produced by producing a magnetic film using a film forming apparatus equipped with a CR plasma irradiation mechanism. More specifically, it is preferable that the ECR plasma irradiation mechanism is directed toward the substrate holder part on which the film is deposited by the ion beam sputtering mechanism. It has also been revealed that the magnetic film produced by this method is effective as a magnetic head material for magnetic recording, a recording medium for magnetic recording, and a recording medium for magneto-optical. The film forming apparatus of the present invention can not only irradiate the substrate with plasma using the ECR plasma irradiation mechanism during film formation to clean the film, but also plasma clean the substrate immediately before film formation. Furthermore, by loading several types of raw materials as a sputtering target, several types of raw materials can be sputtered simultaneously, and a laminated film can also be formed by repeating sputtering of two or more types of raw materials alternately. [Effect l As mentioned above, the ion beam sputtering mechanism and EC
It has been found that a magnetic film with high purity, high density, and low internal stress can be produced by producing a magnetic film using a film forming apparatus characterized by being equipped with an R plasma irradiation mechanism. According to the results of studies conducted by the present inventors, films formed by ion beam sputtering have higher purity than those produced by high-frequency sputtering, which is a conventional film formation method, and as a result, the corrosion resistance of the magnetic film is improved. It was clear that it would improve. In the conventional method, the degree of vacuum during film formation was low, and the film was formed in the presence of residual gas, and impurities were mixed in due to plasma generated inside the film forming container and sputtering the inner wall of the container. It was inferred. On the other hand, in ion beam sputtering, the degree of vacuum is about two orders of magnitude higher than in conventional methods, so the influence of residual gas is small, and since there is no plasma generation inside the container, it has been confirmed that there is little contamination of impurities. When ECR plasma irradiation is performed to form a film, the plasma is irradiated into the container, but almost no decrease in the degree of vacuum was observed due to this. Furthermore, since the irradiated plasma was directed toward the substrate, there was no contamination of impurities due to sputtering on the inner wall of the container. On the other hand, it has been revealed that a film formed by ECR plasma irradiation provides kinetic energy in place of thermal energy to the sputtered deposition particles, and thus has the effect of reducing internal stress generated in the formed film. In particular, it was confirmed that large compressive stress is likely to be applied to a film formed by ion beam sputtering, but the internal stress of a film formed by ECR plasma irradiation is small. Furthermore, it has been revealed that the film formed by ECR plasma irradiation has fewer defects in the film due to kinetic energy, and as a result, a film with high packing density can be obtained. Therefore, a feature of the magnetic film is that a film with a high saturation magnetic flux density can be obtained. In addition, the plasma gas for ECR plasma irradiation may be different from the gas for ion beam sputtering, so oxygen, nitrogen, carbon, boron, etc.

[Example 1] Examples of the present invention will be listed below and will be explained in more detail with reference to figures and tables. [Example 1] A ferromagnetic film mainly containing Fe, Co, and Ni was formed on a glass substrate using the film forming apparatus of the present invention. FIG. 1 shows an outline of the apparatus used in this example. The apparatus of this embodiment is equipped with one ion gun 4, and can perform sputtering on a target 7 on a target holder 6, and deposit sputtered particles on a substrate (not shown) on a substrate holder 10. Further, an irradiation mechanism consisting of an ECR plasma generation section 5 and a gas introduction section 9 is provided toward the substrate, and can perform plasma irradiation during cleaning of the substrate and film formation. The target holder of this device is rotary and can be loaded with up to four types of targets, and any target can be selected for sputtering. Therefore, arbitrary single-layer films and laminated films can be formed from these target materials. By this method, ferromagnetic films mainly containing Fa, Co, and Ni, and films of their oxides, nitrides, carbides, or borides were fabricated. Ion beam sputtering was performed under the following conditions. Ionized gas...Ar Ar gas pressure in the device...2-5X10+2Pa
Ion gun acceleration voltage: 1200V Ion gun ion current: 120mA Distance between target substrates: 130mm Substrate temperature: 50~
ECR plasma irradiation toward the 100° C. substrate was performed under the following conditions. The plasma irradiation gas was Ar. Microwave frequency...2.45GHz Microwave applied magnetic field...875G microwave input...
...100~20OW In this example, the film thickness is 0.5~2μ
A ferromagnetic metal film of m and a ferromagnetic film doped with oxygen, nitrogen, carbon, and boron were fabricated. The obtained film was subjected to A-characteristic evaluation, crystallographic evaluation by X-ray diffraction, impurity evaluation by analysis, measurement of internal stress, and corrosion resistance evaluation by salt spray test in the range of 300° C. to 500° C. Table 1 shows the results. Note that the internal stress was calculated by measuring the deformation of the glass substrate caused by forming the film using a surface roughness meter. In the salt water jet test, a 0.5% NaCl aqueous solution is intermittently sprayed while maintaining the temperature at 30°C, and the amount of decrease in the saturation magnetization of the magnetic film due to corrosion is measured. When the amount of decrease reaches 10%, the corrosion resistance is determined. The number of days. In the table, C and N in the magnetic film were added to the target using carbides and nitrides. The composition of the magnetic film indicates the composition of the target during film formation. As can be seen from Table 1, the saturation magnetic flux density of the obtained films was extremely close to the saturation magnetic flux density of each bulk material, from 0.5T for Ni to 2.1T for Fe. Also,
The internal stress is from -2.4X10l N/m2 to 7.
It shows a compressive stress of 2X10"N/m" and has a corrosion resistance of 30 days.
It was 86 days since the day. Note that films formed using conventional methods such as a high-frequency sputtering device and a dual ion beam sputtering device were also evaluated in the same manner. As a result, Fe formed using high frequency sputtering equipment,
Go and Ni exhibit an internal stress of -2 to 3 x 10"N/m". The internal stress was almost the same as that of the magnetic film formed in the device of the present invention. However, when examining the corrosion resistance, it was found that the corrosion resistance was 10 to 20 days, which was significantly inferior to the magnetic film formed using the apparatus of the present invention. In addition, Fe, Go, and Ni films formed using a dual ion beam sputtering device were formed by setting the acceleration voltage of the ion gun that irradiates the substrate to 500V, and as a result, the saturation magnetic flux density of Fe was 1.9T. C
o is 1.45T. Ni showed a value of 0.45T, which was lower than the saturation magnetic flux density of the magnetic film formed by the apparatus of the present invention shown in Table 1. Also, the internal stress of this film is -3~4X10'N/m t
It showed a large compressive stress of , which was one order of magnitude higher than that of the magnetic film formed by the apparatus of the present invention. However, it was confirmed that the corrosion resistance of various magnetic films formed using the dual ion beam sputtering apparatus was 40 to 90 days, which is almost the same as the corrosion resistance of the magnetic films formed using the apparatus of the present invention. As shown above, the magnetic film formed using the apparatus of the present invention has a higher
It was revealed that the material was excellent in comprehensive evaluation of saturation magnetic flux density, internal stress, and corrosion resistance. Here, the reason why the corrosion resistance of the magnetic film formed using a high-frequency sputtering apparatus is poor is presumed to be due to the high impurity concentration in the film. In addition, the reason why the saturation magnetic flux density and internal stress of the film formed using dual ion beam sputtering equipment is low and the internal stress is large is that Ar ions accelerated with high energy are reflected by the target and implanted into the film, and the substrate is ionized. This is thought to be due to the fact that the irradiated Ar ions are directly implanted into the film, causing defects and compressive stress in the film. When defects occur, the packing density of the film decreases, and therefore the saturation magnetic flux density also decreases. The apparatus of the present invention can eliminate the drawbacks of magnetic films formed by these conventional methods and produce a magnetic film that is excellent overall. [Example 2] Instead of adding carbon, boron, and nitrogen in the magnetic film in Example 1 using carbide, boride, and nitride targets, respectively, the gas species for ECR plasma irradiation was changed from pure Ar to CH4. B2H,, was added by replacing N2 with mixed Ar. Oxygen was also added into the film using a mixed gas of Ar and 02 added. EPMA (electron electron
Micro probe analysis: ElectronP
This is a value measured by the Robe Micro Analysis) method. The amounts of carbon, boron, and nitrogen added were increased compared to Example 1, as shown in Table 2. At this time, the film formation rate increased compared to when film formation was performed using carbide, boride, or nitride targets. This is considered to be because the sputter rate of the metal target is faster than the sputter rate of the carbide, boride, and nitride targets. Other film forming conditions were the same as in Example 1. The obtained films were heat-treated in Ar gas at a temperature of 300°C to 500°C for 1 hour, and the magnetic properties of each film were evaluated.
Crystallographic evaluation by iA diffraction, impurity evaluation by analysis, measurement of internal stress, and corrosion resistance evaluation by salt spray test were performed. As is clear from Table 2, the saturation magnetic flux density of the obtained magnetic film showed a high value similar to that shown in Example 1. Moreover, the internal stress showed a low value of 2.8 to 6.2 x 10"N/m". Furthermore, the number of days of corrosion resistance was 33 to 80 days, indicating excellent corrosion resistance. As shown above, the addition of carbon, boron, nitrogen, and oxygen
As a result of using CR plasma irradiation, it was confirmed that the film formation rate was increased and the obtained film was also excellent overall. [Example 3] In Example 1, the magnetic film was replaced with a product MJII consisting of a ferromagnetic film and an intermediate layer shown in Table 3, and the crystal grains of the ferromagnetic film were made finer to improve its soft magnetic properties. - The laminated film was formed by alternately sputtering two types of targets fixed on a target holder. In other methods, only one type of target is used and the type of gas in the ECR plasma is changed intermittently to achieve multilayer formation. For example, Fe and Fe. C1. The laminated film consisting of
This was achieved by intermittently mixing CH4 into the Ar gas of the R plasma. The results obtained are shown in Table 3. Coercive force and grain size are 50
This is the value measured after heat treatment at 0° C. for 1 hour.6 The crystal grain size was determined from the half width of the diffraction line measured with XgA. The results revealed that the laminated film produced by the apparatus of the present invention is a ferromagnetic film with excellent soft magnetic properties with a coercive force of 1.10e or less. Further, it was confirmed that the crystal grain size at this time was maintained at 200λ or less. As a result of observing the cross-sectional structure of the laminated film heat-treated at 500°C using an electron microscope, the laminated structure was maintained even after the heat treatment, and the laminated structure suppressed the growth of crystal grains in the ferromagnetic metal film. was confirmed. Furthermore, as a result of analyzing these ferromagnetic metal laminated films by high-resolution EPMA method, the present inventors found that the metal added to the ferromagnetic film also gathered in the places where carbon or boron was added, and carbides and borides It was inferred that a was formed. It is presumed that the formation of carbides and borides improves the heat resistance of the magnetic film. [Example 4] A magnetic pole of a metal-in-gap head was produced using the ferromagnetic films obtained in Examples 1 to 3, and evaluated as a head for a high-density magnetic recording device. The substrate is Mn-Zn ferrite, the magnetic film thickness is 5μm, and the gap is 0.3μm.
It is. Glass bonding temperature during head formation is 52
It is 0'C. The medium used has a coercive force of 1500 0
It was s. As a result, the recording characteristics of the head using the Fe-based ferromagnetic film for the magnetic pole of the head were improved by 4.6 dB compared to the conventional Sendust head, and the reproduction output was approximately 3 dB higher. Furthermore, when an Fs-based ferromagnetic film was used for the magnetic pole of the head, a recording density of 100 kBPI or more could be obtained. This is because the saturation magnetic flux density of the Fe-based ferromagnetic film is higher than that of other materials. [Effects of the Invention] As explained in detail above, the film forming apparatus according to the present invention is equipped with an ion beam sputtering mechanism and an ECR plasma irradiation mechanism, thereby eliminating the drawbacks of the conventional technology and achieving particularly high purity, high density, and low A film with internal stress can be created. Furthermore, the magnetic film of high purity, high density, and low internal stress produced using this apparatus exhibits high saturation magnetic flux density and high heat resistance. It has become clear that this material is effective as a magnetic recording medium and a magneto-optical recording medium. The film forming apparatus of the present invention can not only form a film while irradiating the substrate with plasma using an ECR plasma irradiation mechanism during film formation, but also plasma clean the substrate immediately before film formation. Furthermore, by loading several types of raw materials as a sputter target, it is possible to sputter several types of raw materials simultaneously, and it is also possible to form a laminated film by repeatedly sputtering two or more types of raw materials alternately. moreover. A laminated film can also be formed by intermittently changing the plasma gas of the ECR plasma irradiation mechanism to a different gas type. As a result, by laminating the layers, a film with even better soft magnetic properties can be obtained, and the recording/reproducing characteristics and recording density of the magnetic head can be improved. On the other hand, when this high saturation magnetic flux density film was used in a magnetic head of a magnetic recording device, especially when an Fe-based ferromagnetic film was used for the magnetic pole of the head, a recording density of 100 kBPI or more could be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the membrane-shaped commandment device of the present invention. Explanation of symbols

Claims (4)

[Claims] 1. A film forming apparatus comprising at least one ion beam sputtering mechanism and at least one ECR plasma irradiation mechanism in the same vacuum chamber. 2. A film forming apparatus, wherein the ECR plasma irradiation mechanism according to claim 1 is directed toward a substrate holder portion on which a film is deposited and formed by an ion beam sputtering mechanism. 3. A magnetic film of high purity, high density, and low internal stress, produced using the film forming apparatus according to claim 1 or 2. 4. 4. A magnetic film according to claim 3, which is used as a magnetic head material for magnetic recording, a recording medium for magnetic recording, or a recording medium for magneto-optical use.