JPH0312805A - Magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To prevent distortion to be occurred and to control the wear of exposed glass by bonding and fixing the side parts of ferromagnetic metallic thin films and non-magnetic materials with second glass whose softening point is 500 deg.C and less and filling the first glass of high density in glass filling grooves. CONSTITUTION:Second glass 22 and 22 is filled between first glass 21 and 21, namely, on both sides of ferromagnetic metallic thin films 3 and 3 and the non-magnetic thin films 8 and 8. Then, both first and second magnetic core half bodies 1 and 1' are bonded and fixed by fixing second glass 22 and 22 by melting. Namely, a pair of magnetic core half bodies 1 and 1' are bonded and fixed by second glass 22 and 22 which is filled in the ferromagnetic metallic thin films 3 and 3' and the non-magnetic materials 8 and 8' and whose softening point is 500 deg.C and less, and first glass 21 and 21 whose hardness is larger than second glass 22 and 22 in the glass filling grooves 14 and 14. Thus, the peeling of the ferromagnetic metallic thin films 3 and 3 and the occurrence of a crack in the magnetic core half bodies 1 and 1' can be prevented, and a spacing loss owing to the wear of glass which is exposed to a medium sliding surface can be controlled.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a magnetic head used in magnetic recording and reproducing devices such as VTRs (video tape recorders) and DATs (digital audio recorders), and particularly relates to magnetic heads used in magnetic recording and reproducing devices such as VTRs (video tape recorders) and DATs (digital audio recorders). The present invention relates to a composite magnetic head in which a ferromagnetic metal thin film is deposited near the magnetic gap, and a method for manufacturing the same.

(b) Conventional technology In recent years, in magnetic recording and reproducing devices such as ~'TR and DAT, the recording signal density has been increased, and in response to this high density recording, Fe, Co, Ni, etc. Metal tapes with high coercive force using ferromagnetic metal powders such as ferromagnetic metal powders are now being used. For example, a small VTR called an 8 mm video uses a metal tape having a high coercive force of about Hc=1400 to 1500 oersteds. The reason for this is that the need to increase recording density in order to downsize magnetic recording and reproducing devices has led to a demand for recording media that can shorten the recording wavelength of signals.

On the other hand, if a conventional magnetic head made only of ferrite is used to record on this metal tape, the saturation magnetic flux density of the ferrite is about 5,500 Gauss at most, which causes magnetic saturation phenomenon, so the performance of the metal tape cannot be fully utilized. Can not do it. Therefore, for a magnetic head compatible with this metal tape having high coercive force, in addition to the high-frequency characteristics and abrasion resistance of the magnetic core normally required for a magnetic head, the saturation magnetic flux density near the gap of the magnetic core is high. This is required. As a magnetic head compatible with metal tapes that meets this requirement, Japanese Patent Laid-Open No. 60-22
9210 Publication (G], 185/187) etc., the area near the magnetic gap where the magnetic saturation phenomenon is most likely to occur is made of a metallic magnetic material (e.g. ,
A magnetic head (referred to as a composite magnetic head) made of permalloy, sendust, amorphous magnetic material) has been proposed. This composite magnetic head has excellent characteristics in terms of reliability, magnetic properties, wear resistance, etc. This composite magnetic head has the following features: (a), (b), (c) (
There are various shapes as shown in d). In the figure, (1)
(1') is a pair of first and second magnetic core halves made of ferromagnetic oxide material such as M'n-Zn ferrite; (2) is a magnetic gap; body (1)
A ferromagnetic metal thin film (3) such as Sendust is deposited near the magnetic gap (2) of (1"). (4) is the winding groove, and (5) is the above-mentioned This is glass for bonding the first and second magnetic core halves (1) (1').

Among the magnetic heads shown in FIGS. 11(a), (b), (c), and (d), the first and second magnetic core halves (1) (1') and the ferromagnetic metal thin films (3) (3) The magnetic head shown in FIGS. 11(C) and 11(d), in which the boundary portions (6) and (6) are non-parallel to the track width direction of the magnetic gap (2), has a complicated manufacturing process and is not suitable for mass production. .

The manufacturing process of the magnetic head shown in FIGS. 11(a) and 11(b), in which the boundary portions (6) and (6) and the track width direction of the magnetic gap (2) are parallel, is as shown in FIG. 11(c). Although it is simpler than the magnetic head shown in d), the boundary portion (6) (
6) acts as a pseudo gap, causing a waving phenomenon (hereinafter referred to as pseudo gap phenomenon) in the frequency characteristics of the reproduced output. For this reason, for example, in a VTR, the S/N ratio deteriorates, and the D
AT increases error rate.

Also in the magnetic throat shown in FIGS. 11(a) and (b),
As shown in Japanese Patent Application No. 63-167407, the pseudo gap phenomenon described above can be suppressed by interposing a heat-resistant thin film such as 8102 at the boundary.

However, the magnetic head shown in FIG. 11(b)
, ferromagnetic metal thin films (3) (3) are also deposited on both sides of the magnetic gap abutting surfaces of the second magnetic core half (1'). On both sides, three different materials with different coefficients of thermal expansion are adjacent: the first and second magnetic core halves (1) (1°), ferromagnetic metal thin films (3) (3), and glass (5). Therefore, the ferromagnetic metal thin film (3) (3) and the glass (5)
), the bonding force between the first and second magnetic core halves (1) and (1') is also weaker than that of the magnetic head shown in FIG. 11(a).

Considering all the above points, the magnetic head shown in FIG. 11(a) is the most effective.

Next, a method for manufacturing the magnetic head shown in FIG. 11(a) will be described.

First, as shown in FIG. 12, a 5 μm thick ferromagnetic metal thin III (3
') is deposited by sputtering etc., and a non-magnetic thin film (8') such as Sin having a film thickness of half the gap length is deposited on the upper surface of the ferromagnetic metal thin film (3') by sputtering etc. do. After etching and reverse sputtering with a phosphoric acid solution or the like on the L side of the substrate (7), a heat-resistant thin film such as SiO□ having a film thickness of 10 m or more and 1/10 of the gap length or less is applied to the upper surface. (not shown)
may be formed by sputtering or the like, and then the ferromagnetic metal thin film (3') may be formed.

Next, as shown in FIG. 13, a resist (9) is formed on the top surface of the non-magnetic thin film (8゛) using a photolithography technique.
are formed in a predetermined pattern.

Next, as shown in FIG. 14, the nonmagnetic thin film and the ferromagnetic metal thin film other than the resist (9) formation area are removed by ion beam etching to expose the substrate (7), and a predetermined pattern (gap alignment) is removed. ferromagnetic metal thin film (
3) and the non-magnetic thin film (8) are left.

Next, the upper surface exposed portion of the substrate (7) is placed on the upper surface of the substrate (7) as shown in FIG.
As shown in b), groove processing is performed using a rotary grindstone (1o) (H) to form a glass-filled groove (12) as shown in FIG.

Thereafter, as is well known, a pair of substrates (7) shown in FIG. 15 are prepared, and after forming a winding groove and a glass rod insertion groove in one of the substrates, the two substrates are brought into contact with their gap abutting surfaces. A block is formed by glass bonding in this state, and then the block is subjected to processing such as polishing and cutting to form a plurality of Herad chips.

However, in the above manufacturing method, when the pair of substrates (7) (7) shown in FIG. The ferromagnetic metal thin film (3) and the substrate (7) or the heat-resistant thin film act on the difference in thermal expansion coefficient between the ferromagnetic metal thin film (3) and the underlying substrate (7) or the heat-resistant thin film. Strains such as stress occur at the interface with the ferromagnetic metal thin film (3), and the ferromagnetic metal thin film (3) peels off or cracks occur at the interface.

Furthermore, by performing the above-mentioned glass bonding using a glass with a low melting point, it is possible to suppress distortions such as stress caused by the above-mentioned difference in thermal expansion coefficients, but in general, as shown in Table 1 below, Since the hardness of melting point glass is low, the low melting point glass exposed on the media sliding surface in the completed magnetic head is likely to wear out, and if a magnetic head bonded with this low melting point glass is used for a long time, the magnetic medium will drivability deteriorates.

Table 1 Furthermore, in the above-mentioned manufacturing method, in the steps shown in FIGS. When the ferromagnetic metal thin film (3) passes through a nearby portion, the ferromagnetic metal thin film (3) peels off due to the impact, vibration, etc. Furthermore, this film peeling is particularly noticeable when a heat-resistant thin film is formed on the upper surface of the substrate (7).

Furthermore, it is possible to eliminate the above-mentioned film peeling by forming a groove at a location away from the ferromagnetic metal thin film (3), but as shown in FIG. 17(a), the magnetic gap (
On both sides of 2), the magnetic core halves (1) (1') face each other, and the portions (13) (13) may act as a gap and pick up low frequency signals from adjacent tracks.

For example, in the DAT, the portions (13) (13) pick up the pilot signal for the ATF. Furthermore, if a groove is formed at a location away from the ferromagnetic metal thin film (3), the first
As shown in FIG. 7(b), there is a possibility that the position of the magnetic gap (2) may be shifted from the center.

(c) Problems to be Solved by the Invention The present invention has been made in view of the drawbacks of the above-mentioned conventional examples.
A magnetic head that prevents distortion caused by a difference in coefficient of thermal expansion between a magnetic core half and a ferromagnetic metal thin film, and suppresses abrasion of glass exposed on a surface in contact with a medium, and its manufacture. The purpose is to provide a method.

(d) Means for Solving the Problems The magnetic head of the present invention has a softening point of 5, in which a pair of magnetic core halves are filled with a ferromagnetic metal thin film and a non-magnetic material on the sides.
A second glass having a temperature of 00° C. or lower is used to bond and fix the glass, and a first glass having a harder hardness than the second glass is filled in the glass filling groove that regulates the thin film forming surface of the pair of magnetic core halves. It is characterized by

Further, in the method for manufacturing a magnetic head of the present invention, a glass-filled groove is formed on the upper surface of a pair of substrates made of a ferromagnetic oxide material to regulate the width of the thin film forming surface, and a highly hard glass groove is formed in the glass-filled groove. 1, a ferromagnetic metal thin film is formed on the thin film formation surface, and then the ferromagnetic metal thin films on the pair of substrates are brought into contact with each other via a nonmagnetic material that forms a magnetic gap. The step of joining and fixing the pair of substrates by melting and solidifying a second glass having a softening point of 500° C. or less is filled into a gap in which the first glasses of the substrates face each other. Features.

(E) Effect According to the magnetic head having the above structure, the first magnetic head is heated at 600° C. or lower, at which almost no strain occurs between the magnetic core half and the ferromagnetic metal thin film due to the difference in coefficient of thermal expansion between the two. ,
It is possible to join the second magnetic core halves together, and most of the glass exposed on the medium sliding contact surface is made of the high hardness first glass filled in the glass filling groove. Therefore, abrasion of the glass exposed at the medium sliding contact surface is suppressed.

Furthermore, according to the above manufacturing method, the first glass having high hardness is filled before the ferromagnetic metal thin film is deposited.
This heat during filling has no effect on the ferromagnetic metal thin film, and the bond between the magnetic core halves and the pair of substrates 1 is made by melting the second glass, which has a low melting point of 500°C or less. Since this is done by solidification, the pair of substrates are bonded and fixed at a low temperature of 600° C. or lower, where almost no strain occurs between the substrate and the ferromagnetic metal thin film.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the external appearance of the magnetic head of this embodiment, and FIG. 2 is a view showing the tape sliding surface of the magnetic head.

In the figure, (1) and (1') are a pair of first and second magnetic core halves made of ferromagnetic oxide such as Mn-Zn ferrite; Body (1) (1'
) S10! on each thin film formation surface (15) (15)! A ferromagnetic metal thin film (3) (3) such as Sendust is deposited on the ferromagnetic metal thin film (3) (3) through a heat-resistant thin film (not shown) such as A non-magnetic thin film (8) (8) such as 8102 having a film thickness of 172 is deposited. The ferromagnetic metal thin films (3) (3) 2 are attached to the thin film forming surfaces (15) (15) without intervening a heat-resistant thin film.
It may also be formed directly on top. The thin film forming surface (15) (1
5) Glass filling grooves (14) (14) (
14) (14) has the first glass (21) (21) (2
1) (21') is filled. The first and second magnetic core halves (1) (1') are the non-magnetic thin films (8) (8).
The non-magnetic thin film (8
)(s) becomes the magnetic gap (2) with the desired gap length. The first glass (21) of the first magnetic core half (1)
) (21) and the first glass (21) (21) of the second magnetic core half (1°), that is, the ferromagnetic metal thin film (3) (3) and the nonmagnetic thin film ( 8) Both sides of (8) are filled with second glass (22) (22),
The first and second magnetic core halves (1, 1') are bonded and fixed together by melting and assimilating the second glasses (22, 22). The first magnetic core half of the second magnetic core half (1')
A winding groove (4) and a glass rod insertion groove (20) are formed on the surface facing the magnetic core half (1). Said first,
The composition and physical properties of the second glasses (21) and (22) are as shown in Tables 2 and 3 below.

Next, a method of manufacturing the magnetic head of the above embodiment will be explained.

First, as shown in FIG. 3, track width regulating grooves (14) with a depth of 10,071 m are formed on the upper surface of a substrate (7) made of a ferromagnetic oxide material such as Mn-Zn single crystal ferrite, and A thin film forming surface (15) having a width a (for example, 26 μm) slightly larger than the track width of is formed. Note that the upper part of the track width regulating groove (14) is located on both sides (14).
a) (14a) is perpendicular to the upper surface of the substrate (7), and the lower part has a V-shaped cross section.

Next, a plate glass made of a first glass having a softening point of 540° C. is pressed onto the upper surface of the substrate (7) and heated to 560° C. in vacuum to form the track width regulating groove (1).
4) The first glass (21) was filled inside. At this time, glass is also deposited on the thin film forming surface (15). Thereafter, as shown in FIG. 4, the upper surface of the substrate (7) is polished to a mirror surface until the thin film forming surface (15) is exposed. It should be noted that since the track width regulating groove (14) has both upper side surfaces (14a>(14a) perpendicular to the upper surface of the substrate (7), the thin film forming surface (15) ) width a
can be kept constant.

Next, the thin film formation surface (15) of the substrate (7) and the upper surface of the filled first glass (21) are chemically etched with a phosphoric acid solution or the like to remove the process-affected layer due to polishing; After removing impurities by reverse sputtering, the thin film forming surface (15) and the first glass (21)
A heat-resistant thin film (not shown) such as Sin is deposited thereon by sputtering or the like. The thickness of the heat-resistant thin film is 1 nm or more and 1/10 or less of the gap length.

Next, as shown in FIG. 5, the heat-resistant thin film (not shown) is
A 5 μm thick ferromagnetic metal thin film (3') such as Sendust is formed on the top by sputtering etc., and a 5i0 film having a film thickness of 1/2 of the gap length is formed on the ferromagnetic metal thin film (3').
A non-magnetic thin film (8') such as No. 2 is deposited by sputtering or the like. Note that the thin film forming surface (15) of the substrate (7) and the first glass (21
) directly on the ferromagnetic metal thin film (3°) and non-magnetic thin film (8°
') may be formed by adhesion. Next, as shown in FIG. 6, the non-magnetic thin film (8') is
A resist (17) is formed on the upper surface of the portion deposited on the thin film forming surface (15) by photolithography. (17) is the winding groove forming portion (18) and the glass rod insertion groove forming portion (19) of the substrate (7).
) is not formed. In this example, the width is 22 μm.
resist using a photomask with a pattern of)
(17) was formed. Since the thin film forming surface (15) has a width a of 26 μm, it is easy to align a pattern with a width of 22 μm. Further, even if there is a deviation of 1.2 μm, there is almost no problem.

Next, as shown in FIG. 7, the non-magnetic thin film and the ferromagnetic metal thin film other than the region where the resist (17) is formed are removed by ion beam etching to expose the substrate (7). The ferromagnetic metal thin film (3) and non-magnetic thin film (8) of the mating part) are left. The width of the bottom surface (3a) of the ferromagnetic metal thin film (3) is approximately equal to the width a of the thin film forming surface (15), as shown in FIG. By selecting the incident angle during ion beam etching, the inclination angle of the side surface (3b) of the ferromagnetic metal thin film (3) was adjusted, and the width of the bottom surface (3a) was set to a predetermined value.

Next, prepare a pair of substrates (7) (7') shown in FIG.
The winding groove forming part (18) and the glass rod insertion groove forming part (19) of one substrate (7゛) are grooved to form a winding groove (4).
and a glass rod insertion groove (20) are formed, and the gap abutting portions of the pair of substrates (7) (7') are brought into contact with each other as shown in FIG.

Next, the glass rod insertion groove (20) has a softening point of 455.
By heating to 490°C with a glass rod (not shown) made of a second glass inserted therein, the glass rod is melted, and then cooled to melt the pair of glass rods as shown in FIG. Between the first glasses (21) (21) of the substrates (7) (7'), that is, the ferromagnetic metal thin film (3)
(3) and the nonmagnetic thin films (8) (8) are filled with a second glass (22), and the pair of substrates (7) (7°) are bonded and fixed together.

Finally, the joined body shown in FIG. 10 is cut along the broken line A-A' to form a plurality of core blocks, and the end surface of the core block on the medium sliding surface side is subjected to R needle processing. , the core block is cut along broken line B-B' to form a plurality of magnetic heads of this embodiment shown in FIG.

In the above-described magnetic head, the pair of first and second magnetic core halves (1) (1') are made of melted second glass (22) (22) having a low melting point of 455°C. Since the bond is formed by solidification, the heating temperature required for this bond is 490°C.
The temperature after pruning is sufficient, and the first and second magnetic core halves (1) (1
') and the ferromagnetic metal thin film (3) (3) due to the difference in their thermal expansion coefficients can be suppressed.

Furthermore, most of the glass exposed on the medium sliding contact surface of the magnetic head described above is used to control the width of the thin film forming surfaces (15) (15) of the first and second magnetic core halves (1) (1'). The glass filling grooves (14) (14) (14) (14) are filled with a first glass (21) (21) having a harder hardness than the second glass (22) (22). 1rij
Spacing loss during recording and reproduction due to wear of the recording medium sliding surface can be suppressed.

Further, in the method for manufacturing the magnetic head described above, a glass filling groove (14) defining the forming surface (15) of the thin film type 9 is formed, and the glass filling groove (14) is filled with the first glass (21). After that, a ferromagnetic metal thin film (3') and a non-magnetic thin film (8
′), the peeling of the ferromagnetic metal thin film (3′) or the heat-resistant thin film due to the groove processing is prevented. In particular, when a heat-resistant thin film for preventing pseudo gaps is formed, the effect is great. Furthermore, when forming the ferromagnetic metal thin film (3) and non-magnetic thin film (8) of the gap abutting part by ion beam etching, the width a and the width a of the thin film forming part (3) can be adjusted by adjusting the incident angle of the ion beam. The width of the bottom surface (3a) of the ferromagnetic metal thin film (3) can be easily matched with the width of the bottom surface (3a) of the ferromagnetic metal thin film (3). There is no risk of picking up low frequency signals from the truck. or,
The position of the magnetic gap (2) will no longer shift from the center.

(G) Effects of the Invention According to the present invention, by suppressing the strain between the magnetic core half and the ferromagnetic metal thin film, peeling of the ferromagnetic metal thin film and generation of cracks in the magnetic core half can be prevented. Furthermore, it is possible to provide a magnetic head and a method for manufacturing the same that prevent deterioration of recording and reproducing characteristics by suppressing spacing loss due to abrasion of the glass exposed on the sliding contact surface of the medium.

[Brief explanation of drawings]

1 to 10 relate to the present invention; FIG. 1 is a perspective view showing the external appearance of the magnetic head, FIG. 2 is a view showing the tape sliding surface of the magnetic head, FIGS. Figure 5, Figure 6, Figure 7
8, 9, and 10 are diagrams showing a method of manufacturing a magnetic head, respectively. FIG. 11 is a perspective view showing the external appearance of the magnetic head, FIGS. 12, 13, 14, 15, and 16 are views showing conventional methods of manufacturing a magnetic head, and FIG. 17 is a conventional method. FIG. 3 is a diagram showing the tape sliding contact surface of the magnetic head of FIG. (1) (1°)...first and second magnetic core halves, (2)
...Magnetic gap, (3)...Ferromagnetic metal thin film, (7
)...Substrate, (8)...Nonmagnetic thin film, (14)...
・Glass filling groove, (15)...Thin film forming surface, (21)
...First glass, (22 pieces...Second glass. 2 ] 2 Fig. 1 14 Fig. 2 n gin ψ JP-A-3 12805 (10)

Claims (2)

[Claims] (1) A pair of magnetic core halves made of a ferromagnetic oxide material have a thin film forming surface whose width is regulated by a glass-filled groove, and the ferromagnetic metal thin films formed on the thin film forming surface are separated from each other. In a magnetic head in which a magnetic gap extending parallel to the thin film formation surface is formed by abutting each other through a magnetic material, the pair of magnetic core halves are connected to each other by the ferromagnetic metal thin film and the non-ferromagnetic metal thin film. Bonded and fixed with a second glass having a softening point of 500°C or less filled in the side of the magnetic material,
A magnetic head characterized in that the glass filling groove is filled with a first glass having a harder hardness than the second glass. (2) A ferromagnetic metal thin film is deposited near the magnetic gap between a pair of magnetic core halves made of a ferromagnetic oxide material, and the boundary between the magnetic core halves and the ferromagnetic metal thin film tracks the magnetic gap. In a method for manufacturing a magnetic head that is parallel to the width direction, a glass-filled groove is formed on the upper surface of a pair of substrates made of a ferromagnetic oxide material to regulate the width of the thin film forming surface, and a highly hardened material is placed in the glass-filled groove. After filling the first glass, a ferromagnetic metal thin film is formed on the thin film formation surface, and then the ferromagnetic metal thin films on the pair of substrates are brought into contact with each other via a nonmagnetic material that forms a magnetic gap, and the The method includes the step of joining and fixing the pair of substrates by melting and solidifying a second glass having a softening point of 500° C. or less to fill the gap between the first glasses of the pair of substrates facing each other. A method for manufacturing a magnetic head characterized by: