JPH0424426B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for forming a hydrocarbon protective film on the surface of a magnetic storage medium, and in particular a method for forming a hydrocarbon protective film on the surface of a magnetic storage medium such as a magnetic drum or magnetic disk used for video recording, sound recording, computers, etc. by sputtering. Regarding the method. In recent years, in order to improve recording density, methods such as vacuum evaporation, sputtering, and plating have been used to improve the recording density of iron,
A method has been proposed in which a ferromagnetic metal thin film made of cobalt, nickel, or an alloy thereof is formed on a substrate. However, although thin-film metal magnetic storage media created by these methods have excellent high-density recording properties, when used in recording/reproducing devices, for example, the magnetic storage medium and magnetic head etc. do not come into physical contact. , since they run at high speeds, there are problems with wear resistance due to long-term use. In order to improve these, the surface of the magnetic layer is
Methods of forming sputter-deposited films of SiO ₂ , Si ₃ N ₄ , C, and Al ₂ O ₃ are known, but although these protective films are hard, they have a large coefficient of friction and are not magnetic. Since either of the heads may wear out or be damaged, methods have been proposed in which these protective films and lubricants are used in combination. However, this method has the disadvantage that new problems such as spacing loss and head stay tend to occur. The present invention aims to improve these drawbacks, and uses a carbon target in a gas atmosphere containing one or more selected from specific hydrocarbons as a protective film for a magnetic storage medium. By forming a hydrocarbon film on a magnetic storage medium by sputtering, an excellent magnetic storage medium with a low coefficient of friction, excellent wear resistance, and fewer problems such as head stake can be obtained without the use of a lubricant. The present invention aims to provide a method for forming a hydrocarbon protective film on a surface. That is, the present invention uses carbonization of CH ₄ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₆ H ₆ (benzene), etc. when forming a hydrocarbon protective film on the surface of a magnetic storage medium by sputtering. It is characterized by sputtering using carbon as a target in an atmosphere of one or more gases selected from hydrogen. The present invention will be further explained in detail below. The present invention is a method of forming a hydrocarbon film on the surface of a magnetic storage medium by a sputtering method using carbon as a target, but the hydrocarbons used as the atmosphere in the present invention are CH ₄ , C ₂ H ₆ , C ₂ H _{8 .} ,
Hydrocarbons such as C ₂ H ₈ , C ₂ H and C ₆ H ₆ may be used as long as they contain one or more of these gases, or only these gases, but argon (Ar) There is no problem in using gases such as , helium (He), and hydrogen (H ₂ ) in combination. In the present invention, carbon is used as a target,
When sputtering is performed in a gas atmosphere containing one or more selected from the above hydrocarbons, a hard hydrocarbon film containing a large amount of C--H bonds is formed. The protective film thus obtained has a small coefficient of dynamic friction and low internal stress, so it has strong adhesion. Conventional sputtering methods using carbon as a target use gases such as Ar and He alone as atmospheric gases, so
A hard carbon protective film is formed, but no C-H bonds or hydrogen atoms are detected in this protective film, or even if they are detected, they are very small.
This is because the internal stress is large, resulting in weak adhesion and a large dynamic friction coefficient, which is undesirable. In addition to the above-mentioned atmospheric gas, conditions for forming a protective film on a magnetic storage medium include gas pressure, sputtering power source, bias voltage, and reaction time. Since these conditions vary depending on the shape and size of the device, they cannot be particularly limited, but any known conditions can be used. Although it is not necessary to apply a voltage to the magnetic storage medium to which the hydrocarbon film is to be applied in the sputtering process of the present invention, it is also possible to apply a voltage. EXAMPLES The present invention will be explained in more detail below with reference to Examples. Example 1 Manufacture of a plated disk After non-magnetic Ni-P was electrolessly plated to a thickness of 50 μm on a mirror-polished aluminum plate with a diameter of 9 cm and a thickness of 2 mm, the plate was mirror-polished to a thickness of 30 μm, and a first plate was applied on top of the plated plate.
Using the plating liquid shown in the table, Co
Electroless plating of -Ni-P (Co: 80%, Ni: 15%, P: 5%) magnetic film to a thickness of 0.1 μm at pH 7.5 and liquid temperature of 75°C (hereinafter referred to as plating disk A) did. In the pretreatment for electroless plating, Nippon Kanigen Co., Ltd.'s product name "Schuma Sensitizer" and product name "Schuma Activator" were used.

[Table] Next, we used a magnetron type sputtering device manufactured by Tokuda Seisakusho Co., Ltd. (product name ``CFS-8ES'') and high-density carbon (product name ``HCB-18'') manufactured by Hitachi Chemical Co., Ltd. as the target. Sputtering was performed under the conditions shown in Table 2 to form a hydrocarbon protective film with a thickness of 800 Å on the surface of the metal disk A. For comparison, sputtering was performed under the conditions shown in Table 2 (Experiment No. 8) to form a carbon film with a thickness of 800 Å on the surface of the metal disk A.

【table】

[Table] The physical properties shown in Table 3 were measured by the following method. (1) Measurement of dynamic friction coefficient Measurement was performed using the rotating device shown in Figure 1. Head: 2mmφ sapphire ball. Head load: 5g Relative speed: 5m/sec. (2) Measurement of the number of sliding movements The number of sliding movements until the protective film was destroyed was measured using the apparatus shown in Figure 1. Head: 2mmφ sapphire ball. Head load: 10g Relative speed: 10m/sec (3) CSS (Contact Start Stop) Test Using a fixed disk drive device, the number of cycles until head crash occurred was measured. Head: IBM-3350 type, Head load: 9.8g. Rotation speed: 3600r.pm, ON-OFF 30 seconds cycle. Example 2 The reaction time was measured on a 0.5 mm thick silicon wafer.
A hydrocarbon film with a thickness of 1 μm was obtained under the same conditions as in Experiment No. 1 except that the time was 75 minutes. FIG. 2 shows the results of transmission infrared spectroscopic analysis of the silicon wafer coated with this hydrocarbon film. 2870, 2920, 2960, 1420 and 1375 as shown in Figure 2
It was confirmed from the absorption at cm ¹ that C--H bonds were clearly present in this hydrocarbon film. Comparative example: The reaction time was measured on a 0.5 mm thick silicon wafer.
A carbon film with a thickness of 1 μm was obtained under the same conditions as Experiment No. 8 except that the time was 87.5 minutes. FIG. 3 shows the results of transmission infrared spectroscopy of the silicon wafer coated with this carbon film. According to FIG. 3, no C--H bond was observed in this carbon film.

[Brief explanation of drawings]

The drawings show devices used in Examples and Comparative Examples of the present invention, and FIG. 1 is an explanatory diagram of the dynamic friction coefficient and sliding number measuring device, and FIGS. 2 and 3 are examples of Example 2 and Comparative Example, respectively. FIG. 2 is a diagram showing the relationship between the wave number and transmittance of a protective film on a silicon wafer prepared in accordance with an example. Code 1...Magnetic storage medium, 2...Holder,
3...Saphire ball, 4...plate spring, 5...strain gauge, 6...XY stage, 7...motor, 8
... trestle.

Claims (1)

[Claims] 1 When forming a hydrocarbon protective film on the surface of a magnetic storage medium by sputtering, CH ₄ , C ₂ H ₄ ,
The surface of a magnetic storage medium is characterized by sputtering using carbon as a target in an atmosphere containing one or more gases selected from hydrocarbons such as C ₂ H ₆ , C ₃ H ₈ , and C ₆ H ₆ . Method of forming a hydrocarbon protective film.