JPS61192010A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To form track grooves with high accuracy and to attain high accuracy for the track width prescribed by both adjacent tracks, by forming a spare groove at the center of the position where the track grooves are formed concurrently with formation of these track grooves and therefore reducing the cutting resistance in a primary processing mode. CONSTITUTION:The gap forming films 3 and 4 are provided on gap butting faces 1a and 2a of wafers 1 and 2 respectively. Then a winding groove 5 and a glass filling groove 6 are formed on the face 1a in the direction orthogonal to a reference surface 1b. The reference planes 1b and 2b of both wafers 1 and 2 are set on the same level for formation of track grooves 7 and 8. In this process, the spare grooves 17 are cut with a cutting blade with a fixed pitch and the 2/5-3/5 depth compared with both grooves 7 and 8. Then the 1st grooves A are formed successively at a fixed pitch and with prescribed depth at a single side of each groove 17, i.e., toward the planes 1b and 2b. Furthermore the 2nd grooves B are formed successively at the other side of each groove 17 with desired track width (t) secured to the groove A. Thus track grooves 7 and 8 are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic head used in a magnetic recording/reproducing device such as a video tape recorder.

[Conventional technology]

In general, a method for manufacturing this type of magnetic head is disclosed in, for example, Japanese Patent Application Laid-Open No. 168918/1982. A pair of ferrite wafers (1).

+21 respective gap abutting surfaces (Ia), (2B
) are formed by mirror polishing the reference surfaces (lb) and (2b), and then the gap abutment surfaces (Ia),
(2B) is mirror polished. Furthermore, as shown in FIG. 4, a gap forming film (3) made of a non-magnetic film such as silicon dioxide is formed on the abutting surfaces (In) and (2a) of both wafers (1) and (2), respectively.

(4) is applied to both wafers (1) by vapor deposition, sputtering, etc.
, (21) are attached and formed so as to have a desired gap length when butted.

Next, as shown in FIG. 5, a winding groove (5) and a glass filling groove (6 ) is ground and formed, and further, as shown in Figure 6, both sea urchins/% (1)
1 (2) on each butting surface (Ia) and (2a),
A plurality of track width defining track grooves (7) in a direction perpendicular to the winding groove (5) and the glass filling groove (6), that is, in a direction parallel to the respective reference planes (Ib) and (2b).
, (8) is formed. This track groove (7), (
Processing in 8) is performed sequentially at a constant pitch p from a position a certain distance l away from the reference planes (Ib) and (2b), with both reference planes (Ib) and (2b>) aligned on the same plane. A desired track width is also formed between the matching track grooves (7) and (8).

Then, as shown in FIG. 7, both wafers (1)-, (2)
) are joined with the respective butt surfaces (Ia) and (2a) of the respective reference surfaces (It)') and (2b) aligned on the same plane, and then each of the glass filling grooves (6) is A rod-shaped welding glass material (9) is inserted and heated while applying pressure, that is, while pressing the two wafers (1) and (2) together, melting the glass material (9) and forming both wafers (1).
, (2+) to form the block body Gα. At this time, the melted glass material (9) is inserted into the glass filling groove (6
) as well as track grooves (7) facing each other,
(8) also flows into and is filled. Also, both wafers (1)
, (2), a gap of a predetermined width is formed between the abutting surfaces (Ia) and (2a) by both gap forming films (3/, (4)).

Then, the Glock bodies obtained as described above are cut at the cutting plane αη shown by the dashed line in the figure to form a chip block (2), and as shown in FIG. (2) The tape contacting surface is rounded to form a predetermined depth length.

Furthermore, as shown in FIG. 9, a gap abutment surface (11),
With respect to (2a), tape contact defining grooves (to) are sequentially formed at a predetermined azimuth angle so as to have a desired tape contact width m, and the chip block @ is sliced along this groove α1. Then, a magnetic head chip α as shown in FIG. 11 is formed.

Incidentally, in this type of magnetic head, the accuracy of the track width is directly related to the recording density, and as the track width becomes narrower, an accuracy of about 2 .mu.m is required.

As mentioned above, this track width is also determined by the gap abutting surface (Ha) of both ferrite tows (1) and f21.
, (2a) track grooves (7), (8) formed in
Conventionally, track grooves (7) and (8) have been processed using a machine such as dicing in order to perform highly accurate track width processing.

In other words, the track groove machining in the conventional manufacturing method is
As shown in Fig. 12, Huerai Toeba (1),
(2+ gap abutment surfaces (Ia), (2a) are cut into a first groove (AI) parallel to the reference plane (+13), (21)) by a cutting blade α4 called a dicing blade;
(A2), (A3), . . . are sequentially cut at a constant pitch p, and then the first grooves (A2), (AI) are cut.

. . . The second grooves (Bl), (B2), .

[Problem that the invention seeks to solve]

However, when the track grooves are formed by the conventional manufacturing method, there is a large variation in the track widths obtained. This is the first groove (AI).

(A2), (A3), Double-edged surface (X) of cutting blade a1 during 7Ml cutting.

(y) performs cutting equally, cutting surface (Ax), (
Ay), but the second groove ('Bl), (B2),
When cutting ..., one blade surface (X) of the cutting edge α$ obtains the cutting surface (Bx) by cutting only the tip,
The other blade surface ke) is cut over its entire surface to obtain the cutting surface (By), so the other blade surface 0) of the cutting blade α1 is
It is presumed that the frequency of use of the blade surface (y) is high, the wear on the blade surface (y) progresses with respect to one of the blade surfaces (X), and that this is not constant, which directly causes variations in the track width.

Therefore, in order to eliminate the difference in wear between the two edges (X), CY) of the cutting blade α$, the abutting surfaces (la), (
2a), a preliminary groove αG is formed in advance at a constant pitch p, and then a first groove (AI)' is formed.

(A2)', ... and the second groove (B+)', (B
2)', . . . may be sequentially cut.

However, in this way, the double-edged surface (X) of the cutting blade Q5, (
Even if the difference in wear at
), there is no uneven wear in (y).

Note that the cutting edge angle of the cutting blade αQ used for track groove machining is set to approximately 45 degrees in consideration of the problem of track width control and the characteristics of the manufactured magnetic head. When machining, first perform cutting using a cutting blade that is easy to perform cutting (low cutting resistance), that is, a cutting blade with a small cutting edge angle, and then complete the track groove using a cutting blade for main processing. is possible. However, in this case, since two types of cutting blades are used, it is difficult to replace them, and moreover, it is difficult to position the cutting blades, which is disadvantageous.

[Means for solving problems]

In view of the above, the inventors of the present invention analyzed various causes of variations in track width and found that the cutting resistance of the cutting blade for forming track grooves against the wafer has a large influence on this variation. This invention was achieved by confirming that when a preliminary groove is formed before the main processing of the groove, the depth of this preliminary groove greatly affects the cutting force during the main processing and the resulting variation in track width. According to the present invention, in the step of forming track grooves in the method of manufacturing a magnetic head, a preliminary groove is formed at the center of the track groove forming position of the wafer to a depth of 215 to 3/5 of the depth of the track groove. It is characterized by including a process.

[For production]

Therefore, according to the magnetic head manufacturing method described above,
In the step of forming track grooves, first, a preliminary groove is formed at the center of the track groove formation position on each gap abutting surface of a pair of wafers, with a depth of V5 to 3/5 of the depth of the track groove. Then, by performing the main processing on both sides of the preliminary groove, the cutting resistance during the main processing becomes smaller, and accordingly, it becomes possible to minimize variations in track width.

〔Example〕

Next, the present invention will be explained in detail with reference to FIGS. 1 and 2 showing one embodiment thereof.

First, FIG. 2 shows a track groove (7) with a depth of 200 μm.

In the forming process (8), a preliminary groove is formed before the main processing, and the depth of the preliminary groove is varied to perform the main processing of the track groove. be. As is clear from the figure, if a preliminary groove having a depth of 215 to 3/5 of the depth of the track groove to be formed is formed in advance, the track grooves (7) and (8) can be formed by the main processing. ), the track width t
It can be seen that the accuracy is within ±2 μm.

Here, if the machining depth of the preliminary groove is too shallow, the cutting resistance during main machining will increase, the track width accuracy will decrease, and
If the machining depth of the preliminary groove is too deep, cutting fluctuations that occur during the preliminary machining will directly affect the main machining, and stable main machining will not be performed, resulting in a decrease in track width accuracy.

Next, the manufacturing method of the example will be explained.

As explained in FIGS. 3 to 5 of the prior art, the mirror-polished gap abutment surfaces (la) of the pair of ferrite wafers (1) and (2).

A gap forming film +3/ (4) is formed on (2a), and a winding groove (5
) and a glass-filled groove (6) are formed.

Next, the respective reference planes (tb) of both wafers (1) and (21).

(2b) are aligned on the same plane, and a plurality of rows of track grooves (7) parallel to the reference plane (lb) and (2b) as shown in FIG.

(8) In this forming step,
First, as shown by the two-dot chain line in FIG. 1, the depths of the track grooves (7) and (8) are set at the center of the track groove forming position.

For example, 215~3/5 (80tt) for 200μm
Preliminary grooves 0η with a depth of (m−120 μm) are formed at a constant pitch p using cutting blades α4. Thereafter, as shown by the dashed line in the figure, a first groove (A) with a predetermined depth of 200 μm is formed on the negative side of the preliminary groove θ'7), that is, on the reference surface (lb) and (2b). A second groove (B) with a predetermined depth of 200 μm is formed on the other side of the preliminary groove α with a desired track width t left between it and the first groove (A).
) are sequentially formed, and as in FIG. 6, track grooves (7),
(8) is obtained.

Here, if the preliminary groove α force deviates from the center of the track groove forming position, the stability of the cutting blade αG deteriorates during subsequent main processing, and the desired track width cannot be obtained.

Thereafter, the magnetic head chip Q4) as shown in FIGS. 10 and 11 is completed through the steps explained in FIGS. 7 to 9 of the prior art.

〔Effect of the invention〕

As described above, according to the magnetic head manufacturing method of the present invention, in the track groove forming step, a preliminary groove is formed at the center of the track groove forming position with a depth of V5 to 3/5 of the track groove depth. Since the process includes the steps, the cutting resistance during the main machining of the track grooves is reduced, the track grooves can be machined with high precision, and the track width defined by the adjacent track grooves can be obtained with high precision. It is something.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the magnetic head expansion method of the present invention, FIG. 1 is a front view of the main part showing the track groove forming process, and FIG. 2 is a diagram showing the depth of the preliminary groove. Characteristic diagrams of track width accuracy after track groove formation, Figures 3 to 1
Figure 1 shows the manufacturing process in a general magnetic head manufacturing method, Figures 3 to 10 are perspective views, Figure 11 is a plan view of a magnetic head chip, and Figures 12 and 13 are conventional methods. FIG. 3 is a partial front view showing a track groove forming step in the method of manufacturing the magnetic head of FIG. (1), (21-...ferrite wafer, (ta)
, (2a) - Gap butting surface, +3) , (4
)... Gap forming film, (5)... Winding groove, (6
)...Glass filling groove, (7), (8)...Track groove, (9)...Glass material, (2)...Chip block, α knob...Magnetic head chip, n.・Preliminary groove.

Claims (1)

[Claims] (1) A step of forming a winding groove and a glass filling groove on one of the gap abutting surfaces of a pair of wafers made of a magnetic material having mirror-polished gap abutting surfaces, and gap abutting of each of the two wafers. a step of forming a plurality of track grooves for defining track width in a direction intersecting each of the grooves on the surface, joining both the gap abutting surfaces via a gap forming film, and inserting a glass material into the glass filling groove; and a step of slicing the chip block to form a magnetic head chip; and a step of slicing the chip block to form a magnetic head chip. A method for manufacturing a magnetic head, comprising the step of forming a preliminary groove at a depth of 2/5 to 3/5 of the depth of the track groove at the center of the formation position.