JP2537262B2 - Magnetic head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic head. More specifically, the present invention relates to a composite magnetic head in which a ceramic substrate / core and a ferromagnetic metal thin film are combined.

(Prior Art) With the recent increase in density of magnetic recording, a magnetic tape having a higher residual magnetic flux density Br is used, and a magnetic head having a high magnetic flux density and a narrow track width is required to meet this demand. ing.

As such a magnetic head, a conventional magnetic head is disclosed in JP-A-60-22.
As is clear from No. 3012, a thin film of a ferromagnetic metal is formed on a magnetic core made of a ferromagnetic oxide by a vacuum thin film forming technique, and is sandwiched between nonmagnetic materials so that the gap facing surfaces (in this specification, the magnetic gap). A thin film magnetic head is known in which a magnetic gap is formed between thin films of a ferromagnetic metal exposed to a butt joint surface parallel to the.

In this magnetic head, a protective layer for protecting the metal thin film is provided between the metal thin film and the glass for gap bonding. For example, in the magnetic head disclosed in JP-A-60-205808, as shown in FIG. 4, a non-magnetic high hardness film such as Ta ₂ O ₅ , TiO ₂ , or SiO ₂ is formed on the metal thin film 101. A technique of depositing 102 by sputtering or the like is disclosed. In forming the non-magnetic high hardness film 102, an undercoat treatment is performed to form a Cr film 103 of about 0.1 μm in order to improve the adhesion of the high hardness film 102 to the metal thin film 101. For example, in the publication, 0.1 μ
After forming a Cr film of about m, a Ta ₂ O ₅ film of 1 μm on it
Those that have been formed by sputtering or the like with a thickness on the order, or Cr film -SiO ₂ film -Ta ₅ O ₅ film of those formed in this order, or a laminate of a Ti film -TiO ₂ film is disclosed.
Reference numeral 105 in the figure denotes a substrate.

The nonmagnetic high hardness film 102 improves the wettability of the metal thin film 101 to the oxide glass 104. This prevents pinholes from being formed during glass bonding, and prevents the oxide glass 104 from being chipped when used as a head.

(Problems to be Solved by the Invention) However, when forming a conventional non-magnetic high hardness film, in order to improve the adhesion between the metal thin film 101 and the non-magnetic high hardness film 102, the metal thin film 103 of Cr or Ti Presence is needed. This Cr or the like may diffuse into the metal thin film 101 due to heat treatment after the film is attached, deteriorating the metal thin film 101, or making the composition unstable. In addition, since a metal film such as Cr is required on the SiO ₂ film 102 in connection with the subsequent glass bonding process, when a film such as Cr is attached as a base, the protective film has a three-layer structure, which increases the number of processes. There is a disadvantage. Further, when the non-magnetic high hardness film 102 is formed directly on the metal thin film 101 without forming the Cr film 103, the metal thin film 101 and the oxide glass 10
There is a drawback that the deviation due to the difference in the linear expansion coefficient with that of No. 4 cannot be absorbed, and eventually internal stress is generated in the metal thin film 101.

It is an object of the present invention to provide a structure of a protective film which can stably protect the composition of a metal thin film and improve the adhesion to oxide glass to prevent the occurrence of pinholes and the like.

(Means for Solving Problems) In order to achieve such an object, the magnetic head of the present invention is
Between the metal thin film and the oxide glass, a thermally stable and highly hard oxide or nitride layer is formed on the metal thin film, and further glass having good spreadability and oxidized state is formed thereon. A metal layer having good adhesion with is formed, and the surface of the metal film is further oxidized.

(Function) Accordingly, the oxide or nitride film prevents mutual diffusion between the metal thin film and the oxide glass to stabilize the film composition, while the oxidized surface of the metal film enhances the wettability with the oxide glass. To improve adhesion. Then, the metal layer absorbs and relaxes the shift caused by the difference in the linear expansion coefficient between the oxide glass and the metal thin film. This prevents internal stress from occurring in the metal thin film.

(Example) Hereinafter, the structure of the present invention will be described in detail based on an example shown in the drawings.

FIG. 2 is a perspective view showing an embodiment of the magnetic head of the present invention. In this magnetic head, a pair of substrates 1A and 1B are butt-joined with a spacer (not shown) made of a low-permeability material such as SiO ₂ interposed, and a vacuum thin film forming technique such as sputtering is applied to the joint surface, that is, the gap facing surface 3. Is used to form a ferromagnetic metal thin film 4 made of a high magnetic permeability alloy such as Sendust alloy, and a magnetic gap g is formed between the metal thin films 4 of both substrates 1A and 1B. As the substrates 1A and 1B, a ferromagnetic oxide such as ferrite is usually used when it is assumed to be used up to a high frequency of about 5 MHz, but a higher frequency such as 10 MHz is used.
If it is assumed to be used in the vicinity, a ceramic non-magnetic material or the like is used.

The ferromagnetic metal thin film 4 has a side wall surface (hereinafter referred to as a thin film forming surface) 6 of a track groove 13 formed in a gap facing surface 3 parallel to the magnetic gap g, and a gap facing surface 3 and a thin film forming surface 6. It is formed by a known vacuum thin film forming technique so as to have a uniform film thickness along the constituted ridge line 7. Therefore, the thin film 4 has a uniform thickness in the gap depth direction, but becomes thinner toward the bottom of the track groove 13, that is, in the tape sliding direction. But,
The required portion of the metal thin film 4 is in the vicinity of the gap facing surface 3 forming the gap g, that is, in the vicinity of the surface of the track groove 13, and even if the portion apart from the gap g is narrowed, the output characteristic does not cause much problem. This has become clear from the experiments by the present inventors.

In the case of a standard Sendust alloy, the metal thin film is adjusted to a range of 520 to 570 Å, most preferably about 570 Å, and a multilayer film is formed so that the film thickness per layer is about 5 to 6 μm. This structure prevents the output from dropping in the high frequency range.

As shown in FIG. 1, a protective film 2 is formed on the metal thin film 4.
Are formed and filled with the oxide glass 10. Protective film 2
Is a thermally stable and highly hard oxide or nitride film 21, and a metal film 22 and a metal film 22 having good spreadability and good wettability and adhesion with the oxide glass 10 in an oxidized state. And a metal oxide layer 23 forming a surface layer thereof. As the oxide, SiO ₂ or Ta ₂ O ₅ is usually used. This oxide film 21 has a thickness of 0.02
The film thickness is about 0.2 μm, preferably about 0.05 μm. The metal film 22 is usually made of Cr or
Ti is used. The metal film 22 is formed by sputtering or the like to have a film thickness of about 0.02 to 0.2 μm, preferably 0.0
It is formed with a film thickness of about 5 μm. The surface of the oxide layer 23 is, for example, CrO or CrO ₂ .

On the other hand, a recess 8 is formed adjacent to the thin film formation surface 6. The recess 8 is for controlling the track width of the magnetic gap g and for suppressing the generation of the pseudo gap, and the oxide glass 11 is melt-filled. The magnetic head of this embodiment is formed so as to have a predetermined azimuth angle by slightly obliquely slicing when cutting out from a block in which a pair of substrates is joined.

The thin film forming surface 6 is orthogonal to the gap facing surface 3 or
It is preferable to incline at an angle of 100 °.

The manufacturing process of the magnetic head of the present invention will be described below in detail with reference to the processing flow chart of FIG.

First, a large number of rectangular or trapezoidal track grooves 13 extending in a direction orthogonal to the tape sliding contact surface 5 (deep vertical direction) are formed on the gap facing surface 3 of the substrate 1 at a predetermined pitch by grinding [3rd (A)].

Next, the substrate 1 is divided into two along a surface orthogonal to the depth direction, that is, a surface parallel to the tape sliding contact surface 5, to form a pair of substrates 1A and 1B [FIG. 3 (b)].

Then, these are washed and a magnetic thin film 4 of a ferromagnetic metal is formed by using a vacuum thin film forming technique [FIG. 3 (c)].
Usually, the magnetic film 4 is formed by sputtering a ferromagnetic metal such as Sendust alloy. For example, when targeting a standard Sendust alloy, sputtering is about 400Å / m at a substrate temperature of 200 ℃ in an argon gas atmosphere.
It is done at the rate of in. 5-6 per layer of metal thin film
It is preferable to form a substantially multilayer film so as to have a thickness of μm. Usually, the crystal grain size is obtained by intermittently sputtering a ferromagnetic metal or alternately sputtering a ferromagnetic metal and a non-magnetic material. A plurality of magnetic thin films of 520 to 570Å are formed.

After forming the metal thin film 4, the protective film 2 is formed on the film by sputtering or the like [FIG. 3 (d)]. As the protective film 2, first, an oxide film 21 of about 0.05 μm, for example, SiO ₂ or Ta ₂ O ₅ is formed on the metal thin film 4, and a film 22 of metal such as Cr or Ti is formed thereon with a thickness of about 0.05 μm. To form. And the substrate
1A and 1B are heated to about 400 ° C. in the air for several hours, preferably about one hour, to oxidize the surface of the metal film 22.

Then, the substrate 1A, 1B is placed in an inert atmosphere such as nitrogen 4
The high melting point glass 10 is filled and protected in the track groove 13 while being heated to 00 ° C. or higher [glass bonding FIG. 3 (e)]. The glass filling is performed by cooling the protective film 2 after the oxidation treatment described above and then gradually raising the temperature from room temperature again in a nitrogen atmosphere.
It may be carried out after the temperature is kept at 500 to 600 ° C. After that, the gap facing surface 3 and the tape sliding contact surface 5 are ground to form a flat surface having a predetermined surface roughness. Grinding is usually done by lapping to give a mirror finish.

Then, a track regulating recess 8 for eliminating a pseudo gap is ground along the track groove 13 adjacent to the track groove 13. When the recess 8 is ground, the track width formed by the metal thin film 4 is adjusted to be a predetermined width.

After that, the winding groove 12 is formed on the gap facing surface 3 of the one substrate 1A.
Are formed [FIG. 3 (f)]. The winding groove 12 regulates the dips size. The winding groove 12 is not formed on the other substrate 1B.

Next, a spacer (not shown) made of a non-magnetic material such as SiO ₂ is formed on the gap facing surface 3 of both substrates 1 and 1 by sputtering. Then, the pair of substrates 1A and 1B are faced to each other and the metal thin films 4 are butted against each other, and the low melting point glass 11 is filled in the recess 8 for track regulation and bonded [gap bonding FIG. 3 (g)].

After the above gap bonding, the tape sliding contact surface 5 is cylindrically polished to finish the tape sliding contact surface 5 into a curved surface [FIG. 3 (h)].

Next, the magnetic gap g is sliced so as to form a predetermined azimuth angle with respect to the tape sliding direction, and a large number of chip-shaped magnetic cores are cut out [Fig. 3 (i)]. Then, after inspection, it is attached to the support head base, and a sliding surface finishing process is performed to improve the familiarity in the track direction, and the wire is wound [Fig. 1 (j)].

An amorphous metal such as a Co-Zr-Nb alloy can be used as the metal thin film.

(Effects of the Invention) As is clear from the above description, the magnetic head of the present invention has a thermally stable and highly hard oxide or nitride film formed on a metal thin film, and further formed thereon. Since a metal film having good spreadability and good adhesion to glass in an oxidized state is formed and the surface of the metal film is further oxidized, the oxide or nitride film forms a metal thin film and a glass oxide. While preventing the mutual diffusion between them and stabilizing the film composition, the oxidized surface of the metal film enhances the wettability with the oxide glass to improve the adhesion. For this reason, pinholes and the like do not occur when the oxide glass is filled on the metal thin film. Therefore, chipping (chipping) does not occur even when used as a head. Moreover, it is possible to prevent the internal stress from being generated in the metal thin film due to the metal layer absorbing the deviation caused by the difference in the linear expansion coefficient between the oxide glass and the metal thin film.

[Brief description of drawings]

1 is an enlarged sectional view of a metal thin film and a protective film portion of a magnetic head of the present invention, FIG. 2 is a perspective view showing an embodiment of the magnetic head of the present invention, and FIGS. 3 (a) to 3 (j) are FIG. 4 is an enlarged sectional view showing a metal thin film portion of a conventional magnetic head, showing a processing flow chart showing the method of manufacturing the same magnetic head. 1A, 1B ... Substrate, 2 ... Protective film, 21 ... Oxide film, 22 ... Metal film, 23 ... Metal oxide layer, 4 ... Metal thin film, 6 ... Thin film formation surface / track groove side Wall, 10 …… oxidized glass, 13 …… track groove.

Claims (4)

(57) [Claims] 1. A magnetic head comprising a ferromagnetic metal thin film formed on a substrate so as to be covered with an oxide glass, and a thermal head formed on the metal thin film between the metal thin film and the oxide glass. A stable and high hardness oxide or nitride film is formed on the surface of the metal film, and a metal film having good spreadability and good adhesion to glass in the oxidized state is formed on the surface of the metal film. A magnetic head characterized in that a protective film obtained by oxidizing is provided. 2. The magnetic head according to claim 1, wherein the oxide is SiO ₂ . 3. The magnetic head according to claim 1, wherein the oxide is Ta ₂ O ₅ . 4. The magnetic head according to any one of claims 1 to 3, wherein the metal film is Cr.