JPH04243006A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To suppress warpage of a substate and peeling of a ferromagnetic metal thin film and to improve the production yield. CONSTITUTION:On the upper surface 1a of a substrate 1 comprising ferromagnetic oxide material, there are provided a groove 2 to limit the track width and a strain cutting groove 3 which crosses the track width limiting groove 2. Then a ferromagnetic metal thin film is formed on the surface 1a of the substrate 1, and then the surface 1a of the substrate 1 is joined with another substrate with a gap spacer interposed to form a block. In this manufacturing process of a magnetic head, the film thickness (A) of the ferromagnetic metal thin film on the upper surface 1a and the film thickness (B) of the ferromagnetic metal thin film in the strain cutting groove 3 where the thickness is least are determined to satisfy B/A<=0.5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite magnetic head in which a ferromagnetic metal thin film having a high saturation magnetic flux density is disposed near a gap in a magnetic core.

0002

[Prior Art] In recent years, the density of magnetic tapes used in magnetic recording and reproducing devices such as video tape recorders has been increased, and ferromagnetic metal powders such as Fe, Co, and Ni are used as magnetic powders. Metal tapes with high coercive force are now being used. On the other hand, as a magnetic head for recording on this metal tape, for example, JP-A-58-17
As disclosed in Publication No. 5122 (IPC: G11B 5/22), a magnetic material (for example, permalloy, sendust, amorphous magnetic material) having a higher saturation magnetization than ferrite is used as the magnetic core in the vicinity of the working gap. A composite magnetic head composed of
It has excellent properties such as wear resistance.

A method for manufacturing this type of magnetic head is as follows:
A ferromagnetic oxide substrate made of Mn-Zn ferrite etc.
Inclined groove processing, ferromagnetic metal thin film formation, glass filling, grinding,
A pair of core blocks is produced through processes such as polishing and track width regulating groove processing, and the pair of core blocks are joined via a gap spacer using a conventional glass melting method, and then cut into chips at predetermined positions. This method is adopted.

However, in the case of the above-mentioned manufacturing method, if a ferromagnetic metal thin film is deposited by sputtering or the like after forming an inclined groove on a ferromagnetic oxide substrate, temperature changes during sputtering cause the substrate to Distortion occurs between the substrate and the thin film due to the difference in thermal expansion coefficient, and many cracks occur in the substrate during subsequent mirror polishing and track width regulating groove processing.
Yield decreased. As the area to which the ferromagnetic metal thin film is deposited increases, the strain caused by the difference in thermal expansion coefficients described above also increases. For this reason, the dimensions of the ferromagnetic oxide substrate are limited, making it unsuitable for mass production.

[0005]

[Problems to be Solved by the Invention] The present invention was devised in view of the above-mentioned drawbacks of the conventional examples. The purpose of this invention is to provide an excellent method of manufacturing a magnetic head.

[0006]

[Means for Solving the Problems] The present invention forms track width regulating grooves and strain dividing grooves that intersect with the track width regulating grooves on the upper surface of a substrate made of a ferromagnetic oxide material. A method for manufacturing a magnetic head comprising a step of forming a ferromagnetic metal thin film and then bonding the upper surface of the substrate to another substrate via a gap spacer to form a block, the ferromagnetic metal thin film on the upper surface of the substrate. It is characterized in that the film thickness ratio B/A between the thickness A and the film thickness B of the thinnest portion of the ferromagnetic metal thin film in the strain dividing groove is set to 0.5 or less.

[0007]

[Operation] According to the above manufacturing method, the ferromagnetic metal thin film deposited on the substrate is substantially separated at the thin film thickness part within the strain separation groove, so that the substrate and the ferromagnetic metal thin film are separated. The distortion between them is also divided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a magnetic head according to the present invention will be explained in detail below with reference to the drawings.

First, a substrate (1) of a ferromagnetic oxide such as Mn-Zn ferrite single crystal shown in FIG. Slanted groove (2) whose slope (2a) is inclined at an angle of θ as shown in FIG.
A plurality of shapes are formed using a rotating grindstone or the like.

Next, as shown in FIG. 4, the upper surface (1a)
A plurality of strain dividing grooves (3) each having a rectangular cross section are formed perpendicularly to the inclined groove (2). The strain dividing groove (3) is formed to be deeper than the inclined groove (2).

Next, as shown in FIG. 5, a ferromagnetic metal thin film (4) of Sendust alloy, amorphous alloy, etc. is deposited on the upper surface (1a) of the substrate (1) by sputtering, vapor deposition, or ion plating in a vacuum. Deposited using thin film deposition techniques.

Next, as shown in FIG. 6, the inclined groove (2)
After filling the strain dividing groove (3) with glass (5), the upper surface (1a) of the substrate (1) is ground and polished to remove excess glass and the ferromagnetic metal thin film, and the slope (2a) is )
End face (4a) of the ferromagnetic metal thin film (4) deposited on top
expose.

Next, as shown in FIG. 7, the end surface (4a) of the ferromagnetic metal thin film (4) is cut by approximately 1 to 5 μm into the upper surface of the substrate (1) parallel to the inclined groove (2). A track width regulating groove (6) is formed in the magnetic gap, and the width of the end surface (4a) is made to match the desired track width Tw of the magnetic gap.

Next, a pair of substrates shown in FIG. 7 are prepared, and a gap spacer such as SiO2 is formed on the upper surface of one or both of the substrates. Next, as shown in FIG. 8, after forming a winding groove (7) and a glass rod insertion groove (8) on the upper surface of one substrate (1'), the pair of substrates (1) and (1') are The end surfaces (4a) (4a) of the magnetic metal thin films (4) (4) are abutted against each other with a gap spacer interposed therebetween, and then the glass rod (9) is inserted into the glass rod insertion groove (8). By heating and increasing the temperature, the inclined groove (2), the strain dividing groove (3), and the track width regulating groove (6) are filled with glass, and the pair of substrates (1) and (1') are glass-bonded to form a core. A block (10) is formed.

[0015] Finally, the core block (10)
The area near the gap between the pair of magnetic core halves made of ferromagnetic oxide is cut by cutting along the dashed-dot line A-A' and the dashed-double line B-B' and rounded the tape sliding surface. A plurality of composite head chips each having a ferromagnetic metal thin film (4) are formed thereon.

In the above-described manufacturing method, when the step of forming the ferromagnetic metal thin film (4) shown in FIG. 11) and place it at the center O of the target (1).
A straight line (13
) and the perpendicular line (14) to the top surface of the substrate (1) (hereinafter referred to as the incident angle) θ is 0°, the film thickness A of the ferromagnetic metal thin film (4) on the top surface of the substrate (1) The film thickness ratio B/A (see FIG. 1) with the film thickness B of the thinnest part of the ferromagnetic metal thin film (4) in the strain dividing groove (3) is 0.8 (Sample No. 1).
). In this case, the warpage of the substrate (1) after film formation is large, resulting in poor yield in post-processing. Further, as shown in FIGS. 11 and 12, the center Q of the substrate (1) is removed from the center O of the rotary table (11), and the strain dividing groove (3) is aligned with the target (12).
), and the film thickness ratio B/A when the substrate (1) is placed parallel to the tangent line (16) of the concentric circle (15) with a predetermined incident angle θ, and the substrate (1 ) (Samples Nos. 2 to 5). Furthermore, as shown in FIGS. 13 and 14, the center Q of the substrate (1) is removed from the center O of the rotary table (11), and the strain dividing groove (3) is aligned with the target (1).
The film thickness ratio B/A and the condition of the substrate (1) were investigated when the substrate (1) was placed so as to be orthogonal to the tangent (16) of the concentric circle (15) centered on the sample No. 2). 6). Note that the center P of the target (12) and the center O of the rotary table (11) are on the same perpendicular line (17). The above results are shown in Table 1.

[0017]

[Table 1]

As can be seen from Table 1, the film thickness ratio B/A is 0.
When it is 5 or less, the warpage of the substrate (1) after film formation is small, and the processing yield in post-processing is very good.

Furthermore, in the above embodiment, the rotary table (1
1), the film was formed with the substrate (1) rotated, but the same effect can be obtained even if the film is formed with the substrate (1) fixed.

Furthermore, when a plurality of targets (12a) (12b) (12c) are used as shown in FIGS. 15 and 16, each target (12a) (12b) (12c)
) is the center (P1) of each target (12a) (12b) (12c) on the concentric circle of the center O of the rotary table (11).
(P2) and (P3) are located, and the strain dividing groove (3) is arranged so as to be parallel to the tangent of the concentric circle of the center O of the rotary table (11). At this time, the strain dividing groove (3) is a concentric circle (1 8
) is parallel to the tangent line (19). Even in this case,
As in the previous embodiment, if the predetermined incident angle θ is present, the film thickness ratio B/A will be 0.5 or less, so the warpage of the substrate (1) will be reduced and the processing yield will be good.

[0021]

Effects of the Invention According to the present invention, by reducing the strain generated between the substrate and the ferromagnetic metal thin film, the warping of the substrate and the peeling of the ferromagnetic metal thin film are suppressed, and the manufacturing yield is improved. A method for manufacturing a head may be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the state of adhesion of a ferromagnetic metal thin film.

FIG. 2 is a perspective view showing a manufacturing method.

FIG. 3 is a perspective view showing a manufacturing method.

FIG. 4 is a perspective view showing a manufacturing method.

FIG. 5 is a perspective view showing a manufacturing method.

FIG. 6 is a perspective view showing a manufacturing method.

FIG. 7 is a perspective view showing a manufacturing method.

FIG. 8 is a perspective view showing a manufacturing method.

FIG. 9 is a top view showing the arrangement of substrates during film formation.

10 is a sectional view taken along line C-C' in FIG. 9;

FIG. 11 is a top view showing the arrangement of substrates during film formation.

FIG. 12 is a sectional view taken along line D-D' in FIG. 11;

FIG. 13 is a top view showing the arrangement of substrates during film formation.

FIG. 14 is a sectional view taken along line E-E' in FIG. 13;

FIG. 15 is a top view showing the arrangement of substrates during film formation.

16 is a sectional view taken along line F-F' in FIG. 15. FIG.

[Explanation of symbols]

1 Board 1a Top surface 2 Track width regulation groove 3 Strain dividing groove 4 Ferromagnetic metal thin film 10 Core block

Claims (1)

[Claims] 1. After forming a track width regulating groove and a strain dividing groove intersecting the track width regulating groove on the upper surface of a substrate made of a ferromagnetic oxide material, a ferromagnetic metal thin film is formed on the upper surface of the substrate. , a method for manufacturing a magnetic head comprising the step of thereafter joining the upper surface of the substrate to another substrate via a gap spacer to form a block, the film thickness A of the ferromagnetic metal thin film on the upper surface of the substrate and the strain dividing groove. The film thickness ratio B/A with the film thickness B of the thinnest part of the ferromagnetic metal thin film within is 0.
．． 5 or less.