JPH05217117A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a thin film magnetic head excellent in machinability and abrasion resistance against sliding friction by employing beta-SiAlON and TiN as main components of basic material. CONSTITUTION:A basic material 1 for supporting magnetic films 3, 6, an induction coil 4, an insulation layer 2, a protective film 7, and the like is composed of such material as containing beta-SiAlON and TiN as main components. The insulation layer 2 and the protective layer 7 are composed of such material as containing beta-SiAlON or alpha-SiAlON as a main component. Since beta-SiAlON excellent in lubricity, abrasion resistance, strength, and rigidity is dispersed with TiN for imparting conductivity to produce a sintered body excellent in sliding characteristics, abrasion resistance, and machinability, a preferable basic material for thin film magnetic head can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head having excellent durability and wear resistance.

[0002]

2. Description of the Related Art In recent years, magnetic heads, particularly thin-film magnetic heads, are rapidly becoming popular in order to meet the increasing demands for higher recording and higher density in the field of magnetic disk devices. The thin-film magnetic head has a structure in which a thin-film element for recording and reproducing magnetic signals is formed on the rear end surface of a ceramic slider that serves as a substrate. The slider is generated by high-speed rotation (20-40m / s) of a magnetic disk. It has a function to write and read data to and from the magnetic disk by utilizing the fact that it slightly floats above the surface of the magnetic disk (0.2 to 4 μm) by riding on the laminar air flow.

Therefore, the slider cannot obtain a sufficient air laminar flow when starting and stopping the rotation of the magnetic disk.
It always slides on the magnetic disk to perform so-called CSS (contact start stop) operation. Further, even if the slider is flying normally, it is inevitable that the flying height and the flying posture are disturbed by external factors such as vibrations and the intervention of dust. The flying height is becoming smaller in order to increase the recording density, and such disturbance causes the slider to collide with the magnetic disk rotating at a high speed more and more times.

From these points, it is important to improve the slidability of the slider of the magnetic head in order to improve the CSS performance. Furthermore, it is essential that the surface of the slider is smooth, has no pores, and has good wear resistance. Further, the magnetic head is frictionally charged when it comes into contact with and slides on the magnetic disk as described above. If the charge amount becomes excessively large, noise may occur in the magnetic transducer signal winding, and the flying height of the magnetic head may change. Therefore, it is desirable to configure the slider of the magnetic head with a material that does not cause frictional charging as much as possible.

A magnetic head slider is disclosed, for example, in JP-A-55.
Although it has an extremely complicated structure as shown in 163665, in order to make this magnetic head with high productivity, the slider constituent material is machinable, that is, the cutting resistance at the time of processing is small, and the cutting blade. It is important that there be no clogging and that neither cracks nor chipping occur.

As a conventional slider material, Al ₂ O ₃ based ceramics are widely known from the viewpoint of good formability of thin film elements, and many proposals for improvement have been made. For example, JP-A-61-158
862, JP-A-60-231308, JP-A-60-18
3709, JP-A-60-179923, and slider materials containing ZrO ₂ as a main component are disclosed, for example, in JP-A-60-171617 and JP-A-63-278312.
As disclosed in Japanese Patent Laid-Open No. 60-66404, the sliding characteristics and wear resistance are improved.

[0007]

[Problems to be Solved by the Invention]
In the thin film magnetic head of the l ₂ O ₃ -TiC substrate, a long thin film forming process is performed in the order of the base alumina insulating film, the lower magnetic film, the upper magnetic film, the alumina film, the conductor coil, the photoresist organic insulating film and the alumina protective film. Although it was cut and polished, it had the following problems.

Substrates made of Al ₂ O ₃ —TiC have machinability,
Despite excellent wear resistance, when processing a slider with a high precision and complicated shape, cracks and chipping are not small and the processing yield is reduced, and improvement in fracture toughness and sliding characteristics has been strongly desired. In addition, sliders containing ZrO ₂ as the main component are said to have better sliding characteristics than Al ₂ O ₃ —TiC but poor wear resistance and machinability.

Further, when forming a thin film on the above substrate, an insulating film or protective film of alumina is generally used.
Although it has excellent chemical resistance, sufficient adhesion cannot be obtained and stress peeling may occur, and Al ₂ O ₃ has drawbacks such as slow sputtering speed and many problems in the process.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a substrate for supporting a magnetic film, a coil, an insulating film, a protective film and the like is provided with a β-sialon (S
An object of the present invention is to provide a thin film magnetic head characterized by being composed of a material containing i _{6 -Z} Al _z O _Z N _{8-Z and} 0 <Z ≦ 4.2) and TiN as main components.

In the present invention, the insulating film and / or the protective film are formed of β-sialon (Si _6-Z Al _Z O _Z N _8-Z, where 0 <Z ≦ 4.
2) or α-sialon [M _X (Si, Al) ₁₂ (O, N) ₁₆ where 0 <X ≦ 2, M: Li, Y, Mg, Ca, La] Is a thin film magnetic head.

The present invention provides β-sialon (Si _{6 -Z} Al _Z O _Z N _8-Z, which is excellent in lubricity, wear resistance, high strength and fracture toughness, provided that 0
<Z ≤ 4.2) and TiN for conductivity
It is possible to obtain a substrate material composed of a sintered body in which is dispersed, which is excellent in sliding characteristics, wear resistance, and machinability and is suitable for a thin film magnetic head.

In the present invention, the sintered body may essentially consist of a β-sialon phase (Si-Al-ON phase) and a TiN phase. Although it may be used, it may be prepared as a composition that produces these two phases by firing. In general, it is suitable to prepare in advance as a raw material mixture which is produced as a β-sialon phase by firing, and as a TiN phase source in advance as TiN powder.

First, as a raw material for producing the β-sialon phase used in the present invention, a mixture mainly containing fine powder of α-Si ₃ N ₄ , ALN, Al ₂ O _{3 and the} like is usually suitable. As for these raw materials, those having a purity as high as possible, preferably 99% or more and fine, preferably having an average particle diameter of 5 μm or less, particularly 1 μm or less are suitable. Similarly, the TiN that produces the TiN phase should have a purity of 99% or more and an average particle size of 5 μm or less, particularly 1 μm or less.

It is also effective to further finely pulverize these raw materials as a whole mixture. That is, all the raw material mixture is pulverized by using Al ₂ O ₃ balls or the like until the particle size becomes 5 μm or less, preferably 1 μm or less.

The sintered body of the present invention can be obtained, for example, by filling a graphite mold with these mixtures and hot pressing in a vacuum or in a non-oxidizing atmosphere such as Ar or N ₂ . The firing temperature is
The appropriate firing time is 1600 to 1800 ° C, and the firing time is usually 0.5 to 2 hours.

The thus obtained sintered body of the present invention essentially consists of the β-sialon phase and the TiN phase,
Such a β-sialon phase can be easily formed by appropriately selecting the above-mentioned blending ratio of α-Si ₃ N ₄ , AlN and Al ₂ O ₃ which brings about these. For example, α-Si ₃ N ₄ , AlN,
The amount ratio of Al ₂ O ₃ is preferably 2: 1: 1, and the amount ratio of 2: 1.5: 1, which is slightly higher than that of ALN, provides the excellent strength and fracture toughness.

In the sintered body of the present invention, the sialon phase (Si-Al-
The reason why β-sialon is desirable for the ON phase) is the α-sialon phase (Si in Si-Al-ON, Y in part of Al, Y,
It is possible to obtain a material with higher strength and fracture toughness than a solid solution of Ca, Mg, Li, La, etc.). The basis for this is not clear, but α-sialon easily forms a liquid phase and is hot-pressed. At this time, exudation of the liquid phase may occur, which may cause damage to the graphite die or the like, which is not preferable.

In the sintered body of the present invention, at least 30% by weight of these β-sialon phases is necessary, but if the amount is less than 30%, it is difficult to densify and strength and fracture toughness are insufficient.
It is necessary to set the maximum to 70%, and if it is 70% or more, the conductivity is insufficient, and more preferably 65 to 35%.

On the other hand, the TiN phase needs to be at least 30% or more, but if it is less than this, the conductivity is insufficient, while if it is too much, it becomes difficult to sinter, and it is necessary to keep the maximum to 70%. And preferably 35 to 65%.

In the present invention, it is of course possible that components other than these components are contained to the extent that the characteristics of the sintered body of the present invention are not impaired, but it is desirable to keep the amount as small as possible.

In the present invention, the surface is polished by using a substrate material composed of β-sialon-TiN, and a surface roughness Rmax of 0.02 μm or less can be easily obtained with a dense structure having no pores. As such a substrate, various kinds of insulating films and protective films necessary for a thin film magnetic head can be used, but preferable insulating films and protective films include, for example, sialon film. That is, β-sialon (Si _6-Z Al _Z O _Z N
_8-Z where 0 <Z ≤ 4.2) or α-sialon [M _X (S
i, Al) ₁₂ (O, N) ₁₆ However, 0 <X ≦ 2, M: Li, Mg, Y, C
a, La] is used to form an insulating film and a protective film by bias sputtering. This β-sialon-TiN substrate has similar properties to α
Alternatively, by laminating an insulating film or a protective film of β-sialon as a thin film, the adhesion to the substrate material, the stress peeling and the sputter rate, which have been problems in the past, are remarkably improved, and the abrasion resistance and the chemical resistance are also improved. An excellent thin film magnetic head can be obtained.

The formation of such an amorphous film of the present invention will be described with reference to FIG. As shown in FIG. 1, a typical thin film magnetic head of the present invention is an insulating film formed on a β-sialon-TiN ceramic substrate 1 by using a well-known photolithography technique and a thin film forming technique such as a sputtering method, a plating method or a sputter etching method. Layer 2, lower magnetic layer 3,
It can be obtained by forming the protective layer 7 on the upper surface of the head on which the gap layer 5, the coil 4 and the upper magnetic layer 6 are formed.

Since the present invention forms a film using Ar-N ₂ gas by the bias sputtering method using an insulating target of α or β-sialon, it is amorphous, that is, vitreous, and the surface is very smooth and frictional. Abrasion is extremely small.
Also, α or β-sialon target is 500Å / min
Thus, the film formation rate is high, which is advantageous in terms of process. Further, recently, α or β-sialon has been used as a surface protective film for magnetic disks and the like, and when used together, it causes friction between the same materials, and therefore wear resistance such as CSS durability is considered to be further improved.

The optimum thicknesses of the insulating film and the protective film of α or β-sialon of the present invention are about 10 μm and 20 to 50 μm, respectively.

[0026]

In the present invention, the β-sialon-TiN substrate is rich in lubricity, has high strength and high toughness, and has a high thermal conductivity.
Compared with Al ₂ O ₃ -TiC (0.04 cal / cm ・ sec ・ ° C), 0.06 cal
High at / cm / sec / ° C. Therefore, it is considered that a thin film magnetic head having excellent sliding characteristics, excellent heat dissipation, and abrasion resistance against sliding friction can be obtained. It is also a conductive material having a low specific resistance, is excellent in triboelectrification, is dense, has no pores, and has a good surface property. Moreover, this β-sialon-Ti
By stacking a sialon insulating film and protective film, which have the same properties as the N substrate, as a thin film, the adhesion to the substrate is good, there is no stress delamination, the sputtering speed is fast, and the thin film magnetic head is highly reliable. Is considered to be obtained.

Since the β-sialon-TiN substrate formed by laminating these thin films has excellent toughness, high strength and thermal stability, there is no thin film chipping or cracking, and the substrate has excellent machinability and processing steps. It is considered that a thin-film magnetic head with high retention can be obtained.

[0028]

EXAMPLES The present invention will be described below based on examples. Α-Si ₃ N ₄ (10% by volume of β-Si in α-Si ₃ N _4
3 N ₄ included) powder (purity 99 wt%, average particle size 0.5 μm)
), AlN powder (purity 99 wt%, average particle size 1 μm), A
l ₂ O ₃ powder (purity 99.9 wt%, average particle size 0.5 μm) and TiN powder (purity 99 wt%, average particle size 1 μm) were mixed in ethanol solvent using a pot mill to mix well at a predetermined ratio. _It was mixed and ground for 24 hours using a ₂ O ₃ ball. This mixed powder was dried with an evaporator and lightly crushed.

This powder was filled in a graphite mold of a hot press, the pressure was 350 kg / cm ^{2 and the} temperature was 1600 to 1800 ° C., respectively.
Hot pressed in a nitrogen atmosphere for 1 hour, 60 mm φ x thickness 5
A mm sintered body was obtained.

As the physical properties of the sintered body, the density was measured by the Archimedes method and the theoretical density was divided to obtain the relative density, and the bending strength was measured according to JIS R 1601 "Bending test method for fine ceramics". The fracture toughness is SEPB method (S
It was measured by the ingle Edge Pre-cracked Beam method). That is, a sample conforming to JIS R 1601 was prepared, and after applying an indentation by Vickers indentation, a load was applied to create a pre-crack and a pop-in was detected with an earphone.
Subsequently, coloring was performed to measure the precrack length, and a bending test was performed to measure the breaking load. After measuring the pre-crack length of the fractured sample, the fracture toughness was calculated by the fracture toughness calculation formula.

The Vickers hardness was measured by a Vickers hardness meter with a load of 300 g using a mirror-polished surface of a bending test piece. The specific resistance was measured by a 4-terminal method using a bending test piece. 60 mmφ × thickness 5 manufactured by the same method as above
The magnetic head slider was evaluated using a sintered body of mm 2.

The obtained sintered body was mirror-polished, cut with a diamond cutting grindstone, and fine chipping at the corners was observed with a microscope. This chipping test was performed using a resino grindstone with a width of 0.28 mm and a diameter of 52 mm (30 μm).
0.3 incision using a cutter with m diamond diamond
mm The feed rate was 5 mm / sec. Chipping depth is 2
When the thickness does not exceed μm, the slider quality is not substantially affected and the satisfactory quality is maintained, and this is indicated by ◯, and when exceeding 2 μm, it is indicated by Δ and marked chipping is indicated by ×.

The rubbing and abrasion resistance were evaluated by a CSS test in which the sintered body was cut into the shape of an actual thin film magnetic head and brought into contact with a magnetic disk to rotate the disk. The rubbing property was shown by ◯ when the friction coefficient was determined by the CSS test of the disk and the head, and when the friction coefficient was less than 0.5, it was shown by Δ, and when it was significantly large, by x.

The wear resistance was evaluated by repeating CSS trials 10,000 times and checking for scratches on the rubbing surface of the magnetic head slider. As a comparative example, Al ₂ O ₃ -TiC 30% substrate and Y ₂ O ₃ 5.2 wt
% ZrO ₂ -TiC 30% partially stabilized substrate was used for comparison. The respective results are shown in Tables 1 and 2.

[0035]

[Table 1]

[0036]

[Table 2]

As shown in Tables 1 and 2, the present invention has a high density, a small specific resistance, a high bending strength, and a fracture toughness of Al ₂
O ₃ -30% About 1.5 times that of TiC substrate, ZrO ₂ (Y ₂ O ₃ ) -TiC 30
% It shows the same level as the substrate, and in the evaluation as a magnetic head slider, the pores on the surface when mirror-polished were hardly observed and the slider was excellent in chipping resistance, rubbing resistance, and abrasion resistance. Is the best one. Table 3 shows the characteristics of typical magnetic head substrates.

[0038]

[Table 3]

As shown in Table 3, the magnetic head substrate material of the present invention has a higher thermal conductivity than Al ₂ O ₃ -TiC and ZrO ₂ -TiC substrates, so that the friction heat generated by rubbing against the magnetic recording medium is Can be quickly dissipated. Further, since it has a high thermal shock resistance, a highly reliable thin film magnetic head can be obtained without causing a thermal change even if heat is repeatedly applied in the magnetic head manufacturing process.

Next, using the typical magnetic head substrate shown in Table 3, a thin film having the structure shown in FIG. 1 is formed, and an insulating film and a protective film are targets of Al ₂ O ₃ , β-sialon and α-sialon. Was used to compare the adhesion to the substrate, cracking and peeling property (stress peeling), wear resistance, and the film forming rate of each target.

Al ₂ O ₃ was Ar-O by the bias sputtering method using Al ₂ O ₃ and β, α sialon targets.
O ₂ and Sialon are at a total pressure of 5 × 10 ^-3 Torr in Ar-N ₂ gas atmosphere.
Was sputtered. Deposition rates are 240 and 500 respectively
, 500 Å / min, Sialon target is Al ₂ O ₃
The film formation rate was about twice as fast as the target. The results are shown in Table 4.

[0042]

[Table 4]

From the results of Table 4, conventional Al ₂ O ₃ --TiC, ZrO ₂
The -TiC substrate Al ₂ O ₃ insulating film and the protective film is suitable in terms of adhesion and stress peel while wear resistance is poor. The α and β sialon insulation films and protective films have a low coefficient of thermal expansion on conventional substrates and have poor adhesion and are prone to cracking.However, β-sialon-TiN substrates have similar properties and have good adhesion. There was no stress delamination, and the film was an amorphous film, so the abrasion resistance was excellent.

[0044]

The thin film magnetic head of the present invention is a sialon-type.
Due to the excellent lubricity, high strength, high toughness, low resistance, and high thermal conductivity of the TiN substrate, it is possible to provide a thin film magnetic head with excellent wear resistance and mechanical workability against sliding friction with the magnetic recording medium.

As an insulating film and a protective film, Sialon-Ti is used.
A highly reliable thin film magnetic head that improves the efficiency of the thin film integration process with high insulation, chemical durability, compactness and fast film formation rate by using α or β-sialon with high adhesion to the N substrate. Is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view illustrating an embodiment of a thin film magnetic head of the present invention.

[Explanation of symbols]

 1 β-sialon-TiN ceramics substrate 2 sialon insulating layer 3 lower magnetic layer 4 induction coil 5 gap 6 upper magnetic layer 7 sialon protective layer

Claims (4)

[Claims] 1. A thin film magnetic head characterized in that a base material is composed mainly of β-sialon and TiN. 2. The β-sialon and TiN according to claim 1.
The ratio of the former is 70 to 30% and the latter is 30 to 70%
Is a thin film magnetic head. 3. The thin film magnetic head according to claim 1 or 2, wherein the substrate supports the magnetic film, the coil, the insulating film and the protective film, and the insulating film and / or the protective film is mainly composed of sialon. A thin film magnetic head characterized in that 4. The sialon in claim 3 is β-sialon (Si _6-Z Al _z O _z N _{8-Z, where} 0 <Z ≦ 4.2) or α.
− Sialon [M _X (Si, Al) ₁₂ (O, N) _{16 where} 0 <X ≦
2, M: Li, Y, Mg, Ca, La].