KR0179264B1 - Silicon-doft dlc coating magnetic head and manufacture of the same - Google Patents

Abstract

In the magnetic head having a DLC film, a silicon-doped DLC-coated magnetic head which stabilizes the bonding structure of the DLC film by doping silicon to the film formation of the DLC film and a manufacturing method thereof are disclosed. Maintaining at pressure; Injecting a source gas and an auxiliary gas into the vacuum chamber; Forming a plasma in the vacuum chamber and coding the accelerated ions into a silicon doped diamond carbon film; The silicon-doped DLC coated magnetic head is obtained by adjusting the conditions so that the coating layer is maintained at a predetermined thickness. Thus, this silicon-doped DLC coated magnetic head has very good mechanical, optical, thermal and chemical properties compared to conventional DLC thin films.

Description

Silicon-doped DLC coated magnetic head and its manufacturing method

1 is a cross-sectional view showing a state in which the DLC film is coated on the perturbation surface of the magnetic head according to the prior art.

2 is a plan view of the magnetic head of FIG.

3 is a cross-sectional view showing a state where a silicon-doped DLC film is coated on a perturbation surface of a magnetic head according to the present invention.

4 shows an RF plasma coating apparatus for coating the silicon-doped DLC film of FIG.

FIG. 5 is a cross-sectional view of a VCR head to which the magnetic head of FIG. 3 is applied. FIG.

6 is a graph showing a comparison of the friction rate / life of the silicon-doped DLC film and the DLC film of the present invention.

7 is a graph showing a comparison of the friction rate / relative humidity of the silicon-doped DLC film and the DLC film of the present invention.

* Explanation of symbols for main parts of the drawings

24: silicon-doped DLC film R1, R2: curvature

31: magnetic recording medium 32: perturbation surface

33: curved portion 34: coil winding port

35,36: magnetic core 39: laminated glass

40: RF generator 42: the driving direction of the magnetic recording medium

43: vacuum chamber 44: cathode

45 substrate 46 RF power meter

47: matching network 48: DC voltmeter

49: vacuum pump 50: VCR head

51: vacuum gauge 52: control valve

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magnetic heads, in particular silicon-doped diamond-like carbon (hereinafter referred to as DLC) on the perturbation surface of a head composed of a pair of polycrystalline ferrite cores. The present invention relates to a silicon-doped magnetic head suitable for increasing the fixing ability of the silicon doped DLC film and ferrite, the main material of the magnetic head, and reducing the head wear.

In the field of magnetic recording, high frequency of the use frequency and high density of recording are being progressed. In order to increase the recording density, it is required to have high coercive force (Hc) of the tape to be used.

Accordingly, in order for the magnetic head to magnetize a recording medium having a large coercive force, the saturation magnetization value of the magnetic head must be about 6 to 8 times larger than the coercive force of the recording medium (tape, disc) for recording and reproduction.

The iron oxide-based tape currently used uses a manganese-zn ferrite head having a saturation magnetization of 5,000 gauss with a coercive force of 600 to 800 Oe.

However, since the tape used for 8 mm VCR, DAT, etc. has a coercive force of about 1500 Oe, it is difficult to record and reproduce with the head. In order to form an alloy film between gaps or reduce the pseudo-gap effect, a barrier layer is formed of a material such as Cr, SiO ₂ and Fe-N between the ferrite and the magnetic metal film interface and the metal magnetic film is coated.

Such a head is called a MIG (Metal-In-Gap) head.

The MIG head performs track groove and winding groove processing on single crystal ferrite, forms a magnetic metal film on the junction surface of the head gap by sputtering method, and then forms silicon oxide (SiO ₂₎ in the head gap to face the ferrite to form leakage flux. ) The desired magnetic head can be obtained by applying a material, placing a laminated glass in the winding groove, and bonding it to a high temperature, and then cutting it to a certain size.

However, in the magnetic head structure described above, the perturbation surface in contact with the magnetic recording medium is worn out during tape travel, and the wear piece is separated from the constituent material between the magnetic head and the metal-based tape which rotates at high speed. A part of the peeled magnetic thin film causes damage to various components of the magnetic head disposed in the sliding surface of the magnetic head, causing magnetic head wear.

As a part of improving the problem, the perturbation surface 12 of the magnetic recording medium 1 on the upper surface of the magnetic head formed by bonding a pair of magnetic cores 5 and 6 is shown in Japanese Patent Laid-Open No. 4-49508. By coating with a diamond-like carbon (hereinafter referred to as DLC) film having a hard (14) to improve the problems caused above.

However, the technique of coating the DLC film on the perturbation surface creates a gap (gap) between the magnetic head and the magnetic recording medium (tape), resulting in a loss in output.

DLC film thickness

Record wavelength: λ

Therefore, when the recording frequency is 5 MHz, if the DLC film thickness is 1000 Hz, the spacing loss is about 4.7 dB.

Since the allowable range of the scramble fluctuation according to the use of a typical head is about 2dB, the loss of about 4.7dB causes the deterioration of image quality.

Therefore, to overcome this gap loss, it is possible to reduce the thickness of the DLC film first.

Also referring to the plan view of the magnetic head shown in FIG. 2, a pair of magnetic cores 5, 6 of manganese zinc ferrite material is mixed with, for example, a glass material of SiO ₂ + additive. The magnetic gap 4 is formed by joining.

However, the manganese zinc ferrite forming a pair of magnetic cores as described above has a very small affinity with the DLC film to be coated due to the material properties.

In summary, a magnetic head having a DLC film according to the prior art exposes the following three problems.

First, due to the very high compressive stress (about 2GPa), the DLC film has poor adhesion with the coated substrate. That is, the DLC film peels easily from the coated specimen.

Second, the DLC film is thermally very unstable, and easily changes to graphite at about 250 ° C., thereby deteriorating wear resistance.

Third, at high humidity, the coefficient of friction of the DLC film is high (0.1), and the coefficient of friction changes according to the humidity.

Accordingly, the present invention is to solve all the problems exposed in the above-described conventional DLC film, an object of the present invention is silicon-doped DLC stabilizing the bonding structure of the DLC film by doping the silicon on the DLC film before the deposition of the DLC film The present invention provides a coated magnetic head and a method of manufacturing the same.

Another object of the present invention is to provide a silicon-doped DLC coated magnetic head and a method of manufacturing the same, by minimizing wear of the head by coating a silicon doped DLC film on the perturbation surface of the magnetic head.

A feature of the silicon-doped DLC coated magnetic head according to the present invention for achieving the above objects is that the sub-section has a curvature having a Ri curvature and a curvature having a curvature of R2 in the traveling direction of the magnetic recording medium. The eastern surface is covered with a silicon doped diamond carbon film.

In addition, a feature of the silicon-doped DLC coating head manufacturing method of the present invention comprises the steps of putting a magnetic head to be coated in a vacuum chamber and maintaining at a predetermined pressure; Injecting a source gas and an auxiliary gas into the vacuum chamber; Forming a plasma in the vacuum chamber and coating the silicon doped diamond carbon film with accelerated ions; It is made in the step consisting of adjusting the condition so that the coating layer is maintained at a predetermined thickness.

Hereinafter, a preferred embodiment of a silicon-doped DLC coated magnetic head and a control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view showing a state where a silicon-doped DLC film is coated on a perturbation surface of a magnetic head according to the present invention, and FIG. 4 is a view showing an RF plasma coating apparatus for coating the silicon-doped DLC film of FIG. .

First, referring to FIG. 3, the silicon-doped DLC-coated magnetic head of the present invention includes a pair of magnetic cores 35 and 36 formed of a polycrystalline ferrite material, and the magnetic cores 35 and 36 are coil winding holes 34. ) Is provided with a laminated glass material (39) bonded to each other, a perturbation portion (32) having a curvature R1, and a curved portion (33) having a curvature of R2, in the traveling direction of the magnetic recording medium (31). It is formed of a silicon doped diamond carbon film 24 having the surface of the eastern part 32 coated with a predetermined thickness.

Here, the magnetic cores 35 and 36 may be used as polycrystalline ferrites in which SiO ₂ , ZrO ₂ , and V ₂ O ₅ are added to the polycrystalline ferrite composition in order to further increase the output at high frequencies.

In addition, as the laminated glass 39, SiO ₂ + PbO (additive) series may be used.

Further, the silicon doped diamond carbon film has a thickness of 150 GPa or less, and a coefficient of friction between the magnetic recording medium and the magnetic head is 0.1 or less. The silicon doped diamond carbon film is preferably formed to have a hardness of about 20 GPa.

The manufacturing process of the silicon-doped DLC coated magnetic head formed as above will be described in detail with reference to the RF plasma coating apparatus shown in FIG.

In this case, the coating apparatus is also called a plasma enhanced CVD (PECVD) system.

Referring to FIG. 4, the RF plasma coating apparatus is installed in a vacuum pump 49 and a vacuum gauge 51 for maintaining the inside of the vacuum chamber 43 at a predetermined pressure, and in a predetermined region of the vacuum chamber 43. And a cathode electrode 44 including a substrate 45, an RF generator 40 for providing an RF signal to the cathode electrode 44, and an auxiliary gas and a source gas into the vacuum chamber 43. It consists of a control valve 52 for controlling the input of.

In addition, the RF generator 40 includes an RF power meter 46 for setting the RF signal level, a matching network 47 for matching the RF signal level supplied through the RF power meter 46, It consists of a DC voltmeter 48 for setting the supply power to the cathode electrode 44, and an RF signal compensation capacitor and a DC voltage adjusting inductance L.

In addition, cooling water is circulated in the cathode electrode 44 to maintain a constant temperature of the substrate 45.

The above-described configuration is obtained by the following general process of the silicon-doped DLC coated magnetic head of the present invention by an RF plasma coating apparatus.

First, the magnetic head to be coated on the substrate 45 in the vacuum chamber 43 is positioned, and then the vacuum pump 49 is operated to maintain the predetermined pressure until the vacuum gauge 51 is 10 ⁶ Torr.

Next, the source gas CH ₄ and the auxiliary gas SiH ₄ are introduced into the vacuum chamber 43 at a ratio of 1: 4.

In other words, the source gas (CH ₄ ) is 70% to 80% and the auxiliary gas (SiH ₄ ) is 20% in 100% by weight of the total gas injection amount by appropriately controlling a control valve (MFC: Mass Flow Control) 52. Feed it so that it may become% -30%.

Then, when the inside of the vacuum chamber 43 is set to the ion acceleration step by plasma, an amorphous thin film of stable ai (C-H) and ai (Si-O) will be a silicon doped diamond carbon film.

Then, the condition is adjusted so that the coating layer is maintained at a predetermined thickness, the power supply by the RF generator 40 is set to 100 ~ 300W, the acceleration period is 30 ~ 60Sec, the gas pressure is set to 50 ~ 100mTorr It is preferable to keep the temperature of the substrate at 200 ° C. or lower.

In particular, in order to obtain the silicon-doped diamond carbon film having a sp ³ structure in which the C-Si amorphous thin film has a stable electron coupling state, the percentage of the supply power and the reaction gas is very important.

Further, in consideration of the spacing loss formed between the perturbation portion 32 of the magnetic head and the magnetic recording medium 31, the thickness of the thin film is preferably 150 kPa or less.

5 is a cross-sectional view showing a VCR head to which the magnetic head of FIG. 3 is applied.

Referring to FIG. 5, the VCR head 50 is composed of a pair of magnetic cores 35 and is coupled to a magnetic head having a perturbation portion with a magnetic recording medium, and the silicon doped diamond carbon film of the magnetic head ( 24) The magnetic recording medium runs on.

Therefore, FIG. 5 shows that a stable magnetic recording medium traveling direction 42 is formed on the silicon doped diamond carbon film 24.

6 is a graph showing a comparison of the friction rate / life of the silicon-doped DLC film and the DLC film of the present invention, and FIG. 7 is a comparison of the friction rate / relative humidity of the silicon-doped DLC film and the DLC film of the present invention. It is a graph shown.

Therefore, as shown in the drawing, the silicon doped diamond carbon film has a structure that is bonded by the chemical affinity of a-Si inside the carbon matrix and contains microcrystals of several tens to hundreds of microns in size, which is superior to conventional DLC thin films. , Optical, thermal and chemical resistance.

Further, when the magnetic recording medium and the magnetic head are in contact with the perturbation portion, the low friction coefficient (0.1), the high hardness (approx. 20 GPa), the low internal stress and the strong contact force can prevent foreign substances and extend the life of the head.

As described in detail above, the silicon-doped DLC film of the present invention has superior chemical resistance to moisture, acid, alkali solution, and the like compared to the conventional DLC film, and thus, the magnetic head is particularly applied in a region with high relative humidity. In this case, there is an advantage of preventing contamination of the surface of the magnetic head and deterioration of the bonded glass.

Therefore, according to the silicon doped magnetic head of the present invention and a method of manufacturing the same, the silicon doped by plasma ion accelerated coating with an amorphous thin film of ai (C-Si) in an optimal state according to the appropriate condition of the RF plasma coating apparatus Since the diamond carbon film can be obtained, it is apparent that various modulation variations are possible without being limited to the present embodiment presented without departing from the technical spirit of the present invention.

Claims (10)

A silicon-doped DLC coated magnet, comprising a perturbation part having a curvature of R1 and a curvature part having a curvature of R2 in a traveling direction of a magnetic recording medium, wherein the surface of the perturbation part is coated with a silicon doped diamond carbon film. head. The silicon-doped DLC coated magnetic head of claim 1, wherein the silicon doped diamond carbon film has a thickness of 150 μm or less. 2. The silicon-doped DLC coated magnetic head as claimed in claim 1, wherein the coefficient of friction between the magnetic recording medium and the magnetic head is 0.1 or less. 2. The silicon-doped DLC coated magnetic head of claim 1, wherein the silicon doped diamond carbon film has a hardness of 20 GPa. Putting a magnetic head to be coated in a vacuum chamber and maintaining the pressure at a predetermined pressure; Injecting a source gas and an auxiliary gas (SiH ₄ ) into the vacuum chamber; Forming a plasma in the vacuum chamber and coding the accelerated ions into a silicon doped diamond carbon film; Method of manufacturing a silicon-doped DLC coated magnetic head consisting of adjusting the conditions so that the coating layer is maintained at a predetermined thickness. 6. A substrate according to claim 5, wherein the temperature of the substrate is maintained at 200 DEG C or less in a state in which the power supply is set to 100 to 300 W, the acceleration time is 30 to 60 sec, and the gas pressure is set to 50 to 100 mTorr. Silicon-doped DLC coated magnetic head manufacturing method. The method of claim 5, wherein the silicon doped diamond carbon film is a silicon-doped DLC coated magnetic head manufacturing method, characterized in that the coating to a thickness of less than 150Å. 6. The composition ratio of silicon in the silicon doped diamond carbon film is 10% to 20% by weight, and the composition ratio of diamond carbon is 80% to 90% by weight. Silicon-doped DLC coated magnetic head manufacturing method. The method of claim 5, wherein the source gas is CH ₄ . The method of claim 5, wherein the auxiliary gas is SiH ₄ .