JPH01100713A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent peeling or cracking from being generated and to prevent a magnetic characteristic from being deteriorated by constituting a metallic magnetic thin film of a sputter film in which a tensile force remains immediately after sputtering and the sputter film in which compressive stress remains, and arranging the sputter film with the tensile force on a substrate side. CONSTITUTION:The metallic magnetic thin film 4 is constituted of the sputter film 4A in which the tensile force remains immediately after the sputtering and the sputter film 4B in which the compressive force remains, and the sputter film 4A with the tensile force is arranged on the side of the substrates 1A and 1B. Therefore, it is possible to reduce displacement at a boundary part between the substrate whose coefficient of linear expansion is different from that of the metallic magnetic thin film and the metallic magnetic thin film 4 even at the time of rising a temperature such as in a heat treatment time. In other words, even when the temperature of the sputter film 4A with the tensile force adhered on the substrates 1A and 1B whose coefficients of linear expansion are small is increased by performing the heat treatment or filling glass with low m.p., etc., the linear expansion of the sputter film 4A functions in a direction to eliminate the tensile force. In such a way, it is possible to prevent excessive strain between the substrates 1A and 1B and the sputter film 4A with the tensile force from being generated, and to prevent a device from being damaged or deterioration in the magnetic characteristic from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head. More specifically, the present invention relates to a composite magnetic head that combines a substrate made of a ceramic ferromagnetic material or a ceramic nonmagnetic material and a ferromagnetic metal thin film.

(Prior art) As such a magnetic head, conventionally, Japanese Patent Application Laid-Open No. 60-2
No. 23012, a thin film of a ferromagnetic metal, such as Sendust alloy, is formed on a magnetic core made of a ferromagnetic oxide by vacuum thin film forming technology, and is sandwiched between non-magnetic materials to form a gap facing surface (hereinafter referred to as A thin film magnetic head is known in which a magnetic gap is formed between thin films of ferromagnetic metal exposed at a butt joint surface parallel to the magnetic gap.

The ferromagnetic metal thin film, which is important in this magnetic head, is usually formed by depositing a sendust alloy, which has excellent magnetic properties, using a vacuum thin film forming technique such as sputtering.

In addition, as shown in FIG. 5, Cr,
A base material No. 5102 is attached onto the substrate 101, and the substrate 10
In some cases, a metal magnetic thin film is formed by interposing a Cr layer 103 and a 5102 layer 104 between the substrate 101 and the magnetic WA 102 to increase the adhesion between the substrate 101 and the metal magnetic thin film 102. Kaisho 61-3311).

(Problem to be solved by the invention) However, when forming a film by sputtering, the energy of the sputtered particles is much larger than that of vapor deposition, so the increase in adhesive force with the substrate and the internal stress due to the particle implantation effect. This causes various phenomena such as an increase in the amount of carbon, which has a great impact on the strength of the substrate. In particular, since Sendust alloy belongs to a so-called hard and brittle material that is hard and brittle, it has a large amount of internal strain.

In addition, since sputtered films are deposited on ferrite substrates with different coefficients of thermal expansion, if the temperature rises during filling high melting point glass to butt the substrates or during the heat treatment (annealing process), the relationship between the substrate and the film will increase. There is a problem that the amount of Wjg between the two is different, which causes the film to peel off, and cracks to occur in ferrite, glass, etc. Therefore, in manufacturing a composite magnetic head, how to control the internal stress of the sendust film is an essential problem.

For example, when the film stress is tensile, heat treatment (annealing treatment)
Later, the lateral bonding force of the columnar crystals weakened and the magnetic properties deteriorated.
Excessive tensile stress causes the substrate to peel off, while compressive stress results in a dense film with good magnetic properties.
The stress is opposite to that of the substrate and the tensile stress of the glass, which causes cracks and breaks. This tendency becomes obvious when the film thickness becomes 10 μI or more.

The stress remaining in this sputtered film must be controlled to a minimum through heat treatment after glass filling, but its behavior is close to zero after heat treatment when compressive stress is applied after sputtering, and when tensile stress is applied after sputtering. becomes more tensile stress after heat treatment. This is explained by the difference in thermal expansion coefficient between the film and the substrate, that is, the coefficient of thermal expansion of the substrate is smaller than that of the film, and this difference is currently large. This displacement increases as the thickness of the film increases, and the magnetic properties deteriorate accordingly. Therefore, it would be better to make the film extremely thin, but due to the current structure of the head, a certain film thickness is required, and the above-mentioned displacement cannot be ignored. Therefore, in order to improve the magnetic properties, annealing It is necessary to make sure that compressive stress remains before film formation, and reduce the stress to "0" by annealing. However, if compressive stress remains immediately after film formation, it is necessary to use a film with a smaller coefficient of linear expansion than the film. Since the stress is opposite to that of the substrate, etc., the temperature increase during annealing actually acts in the direction of increasing the displacement, which may lead to film peeling and destruction of the substrate, etc.

In addition, when attaching Cr etc. to the film forming surface in advance, C
The effect is recognized as the underlying layers 103 and 104 of r and 5i02 are thicker, in the range of 300 Å or more and several thousand people.

However, on the other hand, when the underlayer becomes thicker, the magnetic continuity between the substrate 101 and the metal magnetic thin film 102 is lost, the magnetic properties deteriorate, and a pseudo gap is output. Forming ultra-thin layers of ~ several thousand layers is difficult to control and is fraught with manufacturing hassles.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic head that can be easily manufactured without peeling of a metal magnetic thin film or cracking of a substrate, etc., and which exhibits less deterioration of magnetic properties.

(Means for Solving the Problems) In order to achieve the above object, the magnetic head of the present invention comprises a sputtered film in which tensile stress remains and a sputtered film in which compressive stress remains immediately after sputtering a metal magnetic thin film. , a sputtered film with tensile stress is placed on the substrate side.

(Function) Therefore, even if the temperature of a sputtered film with tensile stress that is in close contact with a substrate with a small coefficient of linear expansion is increased by heat treatment or filling with high melting point glass, the linear expansion of the sputtered film will eliminate the tensile stress. Since it acts in the direction of compression, that is, in the direction of compression, the displacement at the boundary between the substrate and the metal magnetic thin film, which have different coefficients of linear expansion, is small and does not cause damage.
That is, as shown in Figure 2, the stress of the entire film of the metal magnetic thin film immediately after sputtering is as follows for a film with only compressive stress (
(indicated by symbol ■) is closer to the tensile stress side (indicated by symbol ■)
So, when annealing is applied to reduce the stress to ``0'' (
(indicated by symbol ■), the film and substrate will not be destroyed or cracked during the temperature rising process due to stress or the like.

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

FIG. 1 (A>, (B) i (C) shows an embodiment of the film structure of the present invention. The metal magnetic thin film 4 has a sputtered film 4A in which tensile stress remains immediately after film formation and a sputtered film 4A in which compressive stress remains. The tensile stress sputtered film 4B is arranged on the substrate 1 side.

The tension sputtered film 4A and the compression sputtered film M4B may be formed to have approximately the same thickness as shown in FIG. 1(A), or
As shown in FIG. 1(B), tensile sputtering M4A and compressive sputtering film 4B are alternately and repeatedly formed to obtain a sputtered film 4 of a predetermined thickness, or as shown in FIG. 1(C). As such, the stress generated between the film and the substrate is slightly alleviated by 1! At the same time, the tensile sputtered film 4A, which is unfavorable for magnetic properties, may be made as thin as possible.

Hereinafter, the manufacturing process of the magnetic head of the present invention will be explained in detail based on the drawings.

First, on the surface of the substrate 1, for example, the gap facing surface 3, a large number of rectangular, ■-shaped or trapezoidal track grooves 13 are formed at a predetermined pitch by grinding, extending in a direction perpendicular to the tape sliding surface 5 (in the transverse direction). Figure 3(a)).

Next, this substrate I is divided into two parts along a plane perpendicular to the above-mentioned transverse direction, that is, a plane parallel to the tape sliding surface 5, and a pair of substrates I are separated.
A and IB are formed [Fig. 3(b)].

Then, these are cleaned and a thin metal magnetic thin M4 of ferromagnetic metal is formed using vacuum thin film forming technology so that it has a uniform thickness along the ridge line 7 [Fig. 3(c)]. The thin film 4 is formed by sputtering a ferromagnetic metal such as Sendust alloy. Sputtering is
For example, when targeting standard Sendust alloy, approximately 400 people/person at a substrate temperature of 200°C in an argon gas atmosphere
This is done at a rate of min. At this time, the metal magnetic thin film 4
The internal stress of the thin film is monitored during sputtering using a known strain measuring means such as a strain gauge, and the sputtering conditions and the pressure of Ar gas introduced are feedback-controlled so that a predetermined stress remains.

In the sputtering method, it is generally known that the internal stress of the formed film can be controlled by changing the pressure of introduced gas (Ar). When the introduced gas is low, the stress is compressive, and when the gas is high, the stress is tensile. Therefore,
As shown in Figure 1, for example, the introduced gas pressure is 6.0w+TO.
A tensile stress sputtered film 4A was formed as rr, 4,
A sputtered film 4B with a compressive stress of 0 +mTOrr is formed.0Although not shown in the figure, the strain gauge is
It is attached to the back surface of the substrates IA and IB or is formed directly on the back surface. Substrates IA and IB generally exhibit curvature determined by their shape, elastic constant, and the magnitude of stress in the thin film. Therefore, by measuring the substrates IA and IB using a resistance wire strain gauge, the internal stress of the film can be measured. Can be measured. The initial setting compressive stress given to the compressive stress sputtered film 4B is, for example, 4 to 8 (X 109 dyn/j
), and the initial setting tensile stress given to the tensile stress sputtered film 4A is preferably set in the range of, for example, 0 to 4 (X 109 dyn/aJ). Magnetic thin M4 is usually -
It is preferable to form a substantial multilayer film with a film thickness of 5 to 6 μm per layer. Therefore, by sequentially forming a film of a ferromagnetic metal by a sputtering method, By forming films of non-magnetic materials alternately by sputtering method, the crystal grain size of the 422 planes (or 211 planes) of the crystal is 520 to 570 people, while the crystal grain size of the 220 planes of the crystal is 200 to 300 people. At this time, by repeatedly applying initial stress in the order of tensile stress → compressive stress → tensile stress → compressive stress (see Figure 1 (B)), the stress of the entire film can be reduced to the value shown in Figure 2. In addition, as shown in FIG. 1(C), the tensile stress sputtered film 4A may be made considerably thinner than the compressive stress film 4B, and the substrate It is also possible to improve the magnetic properties by minimizing stress relaxation at the boundary between the film and the thin film.In this case, the compressive stress [4B may be a single layer or a multilayer film. .

Next, while monitoring the electrical resistance of the metal magnetic thin WA4, annealing is performed to achieve the stress state shown in Figure 2. Normally, the annealing temperature at this time is 500 to 600.
℃ range.

Next, the track groove 13 is filled with high melting point glass 10 to protect the metal magnetic thin JIW 4 [Glass bonding FIG. 3(d)].

Thereafter, the gap facing surface 3 and the tape sliding contact surface 5 are ground, and the excess glass and metal magnetic thin film 4 is ground to remove the excess glass and metal magnetic thin WA 4 and the connecting portion of the monitor lead wire. The surface should be flat with no roughness.

Grinding is usually done by lapping to give a mirror finish. As a result, a track is formed on the end face of the metal magnetic thin film 4 formed on the thin film forming surface 6.

Thereafter, a recess 8 is ground next to the aforementioned track groove 13 along the groove 13 to eliminate a false gap [third
Figure (e)].

After that, the wire is wound on the gap facing surface 3 of one board IA. 1
112 [FIG. 3(f)], this winding wire 12 regulates the depth dimension 6, and then both substrates 1^, 1B
A spacer (not shown) made of a non-magnetic material such as S i 02 is formed on the surface facing the gap by a sputtering method.

Next, the pair of substrates IA and IB are faced to each other and the metal magnetic thin WA4 pieces are butted against each other, and the recess 8 is filled with low melting point glass 11 and bonded [gap bonding FIG. 3(g)].

After the above-mentioned gap bonding, tape bonding is performed [Fig. 3(h)].

Next, the tape is sliced diagonally so that the magnetic gap g takes 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)].

After that, it is inspected and installed on a support, and the sliding surface is finished to improve its conformability in the track direction, and then the wire is wound [Fig. 3 (j)].

Note that the present invention is not limited to the magnetic head manufactured by the above-mentioned manufacturing method, but can also be applied to a pair of substrates I on which a sputtered film 4 of ferromagnetic metal is formed on the entire surface of the gap-opposing surfaces, as shown in FIG.
A so-called MIG type magnetic head or a ferromagnetic metal head is produced by inserting a track forming groove 13 into a head block 1 in which A and IB are butt-jointed to form a gap, forming a track, slicing it into a predetermined width, and cutting out a head chip. Needless to say, the present invention can be applied to any magnetic head having a combination of sputtered film 4 and an oxide substrate.

Furthermore, the present invention can also be applied to cases where amorphous metals such as Co-Zr-Nb alloys are used as thin film materials.

(Effects of the Invention) As is clear from the above description, the present invention comprises a metal magnetic thin film consisting of a sputtered film in which tensile stress remains immediately after sputtering and an i < ivy film in which compressive stress remains. Since a sputtered film with tensile stress is placed, there is little displacement at the boundary between the substrate and the metal magnetic thin film, which have different coefficients of linear expansion, even when the temperature rises during heat treatment, preventing the substrate or the metal magnetic thin film from breaking or peeling. In other words, even if the temperature of a sputtered film with tensile stress that is in close contact with a substrate with a small coefficient of linear expansion is increased by heat treatment or filling with high melting point glass, the linear expansion of the sputtered film will not reduce the tensile stress. Since it acts in the direction of canceling the stress, excessive strain does not occur between the substrate and the tensile stress batter film, and no breakage occurs.

In addition, this magnetic head uses a sputtered film with residual tensile stress on the part that comes into close contact with the substrate, so the magnetic properties are slightly degraded, but since it uses the same material as the metal magnetic thin film, the relationship between the metal magnetic thin film and the substrate is Compared to the case where a non-magnetic material is interposed between the two to impair the magnetic flux flow, the magnetic properties do not deteriorate as much.

In addition, since this magnetic head does not include a non-magnetic material, it is magnetically continuous and there is no risk of pseudo gaps occurring, and stress control is possible with the same Sendust alloy, so when a non-magnetic material is used. It is easy to manufacture as it does not require precision in film thickness compared to .

[Brief explanation of the drawing]

FIGS. 1A, 1B, and 1C are enlarged sectional views of a metal magnetic thin film portion showing an embodiment of the magnetic head of the present invention. Figure 2 is a graph showing 1% of the residual stress in the metal magnetic thin film and the argon gas pressure introduced during sputtering, Figure 3 is a processing process diagram showing an example of the manufacturing process of a magnetic head, and Figure 4 is a graph showing 1% of the residual stress in the metal magnetic thin film and the argon gas pressure introduced during sputtering. FIG. 5 is an enlarged sectional view showing a metal magnetic thin film portion of the conventional magnetic head. 4...Metal magnetic thin film, 4A...Sputtered film with residual tensile stress, 4B...
A sputtered film with residual compressive stress. Patent applicant: Sankyo Seiki Seisakusho Co., Ltd. No. 2'vA Figure 5

Claims (4)

[Claims] (1) In a magnetic head in which a gap is formed by abutting a pair of substrates each having a thin film formation surface on which a metal magnetic thin film is formed by sputtering, tensile stress remains in the metal magnetic thin film immediately after sputtering. 1. A magnetic head comprising a sputtered film with residual compressive stress and a sputtered film with residual compressive stress, the sputtered film with tensile stress being disposed on the substrate side. (2) The magnetic head according to claim 1, wherein the tensile stress sputtered film and the compressive stress sputtered film have approximately the same thickness. (3) The magnetic head according to claim 1, wherein the metal magnetic thin film is formed by alternately laminating tensile stress sputtered films and compressive stress sputtered films to a predetermined thickness. . (4) The magnetic head according to claim 1, wherein the metal magnetic thin film is a tensile stress sputtered film that is considerably thinner than a compressive stress sputtered film.