JPH01211312A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To eliminate the variation of a track width until the gap depth becomes zero by using a rectangular groove for deciding the track width and another rectangular groove for deciding the gap depth '0' and causing the intersecting two sides of two through holes to intersect at their straight line parts. CONSTITUTION:The gap depth gd and track width Tw of a magnetic gap section are respectively regulated by means of two etching grooves 71 and 72 provided on an insulating film 4. Moreover, the magnetic gap section is formed of a through hole 7 which is formed through the insulating film 4 by intersecting the 1st rectangular groove 72, whose width W1 is wider than the track width Tw and length in the longitudinal direction of the magnetic path is gd, and the 2nd rectangular groove 72, whose width is the track width Tw and length l2 in the longitudinal direction of the magnetic path is longer than the gd, at right angles in the area where the ridge lines of the grooves are straight lines. Therefore, the magnetic gap section becomes rectangular in shape and the variation of the track width as the gap depth becomes shallower can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a type of thin film magnetic head that slides over a recording medium, and particularly relates to highly accurate track width control. [Prior Art] VTR In systems where the head runs in contact with a recording medium such as the above, there is a serious issue of ensuring wear life, and one way to apply a thin film magnetic head is to develop one with a large gap depth. To this end, in order to guide the magnetic flux to the tip of the gap, the core thickness must be increased so that the magnetic core does not become saturated on the way.According to the study results of the present inventors, it is necessary to increase the gap depth to ensure wear life. 10 to 15 .mu.m is required, and therefore the upper and lower magnetic cores need to have a thickness of about 20 .mu.m.

However, it is not easy to form such a thick N film by high-precision patterning, and in a thin film magnetic head, there is a part in the patterning part where the magnetic film formed on the slope part is processed. Because there is a large difference in the etching speed of the magnetic film between the top and flat parts, so-called wet etching cannot be used, and a dry etching process called ion milling is used, but this method has drawbacks such as lack of selectivity. The mask material used during processing needs to be as thick as the magnetic film.

It is extremely difficult to etch a film as thick as 20 μm with high precision. In other words, the track width accuracy is poor. Therefore, as a conventionally proposed method, for example, as described in JP-A No. 61-255514, a through hole is provided in the head gap forming part of the coil insulating layer, and the trunk width is controlled by the width of this through hole. There is something to do.

[Green Problem 1 to be Solved by the Invention] According to the above-mentioned conventional technology, the target for highly accurate patterning is changed from a 20 μm magnetic film to an approximately 10 μm insulating film, and the film thickness can be halved and the etching precision can be improved. goes up.

However, in this technique, no consideration is given to the track width accuracy in the gap depth direction, and there is a problem in that the trunk width becomes narrower as the gap depth approaches zero (the position where the life ends).

The situation is shown in FIG. (a) is a perspective view, and (b) shows a plan view of a through hole provided in an insulating layer. W
The track width 1gd is the gap depth.

The corners of the through hole are rounded, and the track width decreases near zero gap depth. Therefore, when considering compatibility, performance stability, etc., the gap depth that can actually be used is gd'. In other words, when ensuring the running life, the head performance had to be used at a level lower than its original performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film magnetic head whose cap depth gd is -1 which can be used in actual use as it is, that is, the track width does not change in the gap depth direction.

[Means to solve the problem]

The above object is to eliminate at least two rectangular grooves whose width in the track width direction is equal to the track width and a rectangular groove whose width is larger than the track width, which are provided in the coil insulating film so that the ridge lines of the grooves are perpendicular to each other in the linear region. This is achieved by using the through hole of the coil insulating film formed at the overlapping portion of the two grooves as the gap forming surface.

[Effect]

The track width is determined by one rectangular groove and the zero gap depth is determined by another rectangular groove. Moreover, the two sides where the two through-holes intersect are orthogonal to each other at the straight edge. As a result of the above, there is no change in track width until the gap depth is zero.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1 and FIG. 2 1ζ. FIG. 1(a) is a perspective view of a thin film magnetic head of the present invention, and FIG. 1(b) is a cross-sectional view thereof. , 2 is a perspective view of the gap forming part before the formation of the upper core, in which 1 is the substrate, 2 is the lower magnetic core, 3 is the gap material, 4 is the insulating film of the coil conductor, and 5 is the coil conductor (one turn only). ), 6 is the upper magnetic core, 71.72 is the first . Second etched groove.

7 is the first. A through hole made by etching grooves $2 is the head gap forming surface, and 8 is a through hole for connecting the lower magnetic core 2 and the upper magnetic core 6.

In FIG. 1, the thin film magnetic head has a signal coil 5 disposed within a magnetic circuit formed by a lower magnetic core 2 and an upper magnetic core 6 embedded in a substrate 1 via a gap material 3. The gap portion has a cap depth gd and a track width Tw defined by two etched grooves 71 and 72 provided in the coil insulating film 4, respectively. In this example, the magnetic core thickness 2.6 is 20 μm, and the coil insulating film 4
is 12 μm, and the depth of the first and second etching grooves is 6 each.
It was set as μm.

This magnetic gap portion will be explained in detail with reference to Figure Wc2.0 The magnetic gap portion has a rectangular first etching m71 whose width (W) is wider than the track width (Tw) and whose length in the magnetic path direction is gd, and the width The rectangular second etched grooves 72, which are longer than the track width (Tw) and the length in the magnetic path direction (it) ps, gd, are formed so as to be perpendicular to each other in areas where the groove ridge lines are straight lines. , a through hole 7 formed through the coil insulating layer 4I.Therefore, the magnetic gap portion is rectangular, and the track width does not change depending on the gap depth.

Next, we will briefly explain the manufacturing method of this head.

(1) After forming S for the lower magnetic core on the substrate using a dicing saw or ion milling,
- 20 μm of magnetic film such as 8i system is formed by sputtering,
Polishing (making the lower magnetic core 2 embedded in the substrate).

(2) As a cap material, Ano! An insulating film such as 0.03 or a metal film such as Cr is formed to a thickness of about 0.3 μm by sputtering.

(3) Using Cr of about soo X as an adhesive layer, Cu
is steamed to a thickness of 5 fim and patterned by ion milling to form a coil conductor 58 (however, if a metal film is used as the gap material, the coil conductor 5 is formed after passing through an insulating film such as SiO!)0 (4) SiO+5iOz etc. with a thickness of 12 μm that can be easily selectively etched as a gap material
In addition to insulating the coil conductor 5, the upper and lower cores are spaced apart from each other.

(5) The first etched groove 71 is made to a depth of 6 μm by ion milling, reactive ion etching, etc., and then the second etched groove 72 is formed at a position perpendicular to the first etched groove, and at the intersection of both grooves. Form a through hole 7 in the coil insulating film 40 (6) Etch the coil insulating film 4 of the core connection portion 8 (note that these may be formed at the same time when forming the first and second etching grooves)0 (7) ) After forming a magnetic film with a thickness of 20 μm, it is patterned into a core shape by ion milling.

By making it as described above, it is possible to solve the change in track width near zero gap depth. Through acceptance like this
Being able to eliminate the radius at the corner of the coil also has the effect of improving head efficiency by reducing the magnetic path, or increasing the coil winding space and lowering the resistance of the coil, thereby improving performance.

Furthermore, since the second etching groove that determines the track width is etched to be thinner than the conventional coil insulating film (6 μm in this embodiment), there is also the effect of improving the track width accuracy. In the above embodiment, the first. Regarding the order of the second etching, if the order is changed and the second etching grooves that determine the track width are formed first, the track width will be determined by patterning on the flat portion, and the accuracy of the rough track width will be improved.

The above explanation is for the case of a single-layer coil, and the through-hole forming process is increased by one step compared to the conventional method. However, when applying the present invention to a thin-film magnetic head having a two-layer coil, the process is more than the conventional one. It can be made without increasing the number of steps. The manufacturing method in that case will be explained with reference to FIGS. 3(a) to (i).

(a) Make the lower magnetic core 28 embedded in the substrate.

(b) Form the gap material.

(e) First insulating layer 4 for insulation from the coil conductor
1 (can be omitted if it is not a metal film gap).

(d) After forming the first coil conductor 51 of the multi-turn coil, it is insulated with the second insulating layer 42.

(e) Connection part between the first coil conductor and the second coil conductor (
The second insulating layer 42 (not shown) is removed by etching.

At this time, a first through hole 7a and a core connecting portion 8a corresponding to the first etching e71 (FIG. 2) are formed at the same time. Also, resist Jl! , and at the same time flatten the irregularities of the coil using a flattening method called an etch-back method.

(f) Forming a second coil conductor 528.

(2)) Similarly to the second insulating layer M42 forming the fifth insulating layer 43, it is planarized by an etch-back method, a bias sputtering method, or the like.

(h) A second groove corresponding to the Ka2 etching groove 72 (Fig. 2).
A through hole 7b is opened to form a through hole 7 formed in the coil insulating film which will serve as a gap forming surface. At the same time, the third insulating layer 43 of the core connection portion 8bUJ is also removed.

This second through hole can be formed at the same time as planarization by optimizing the resist thickness in the etch-back method described in 1999.

(1) Even when the upper magnetic core 6 has a two-layer coil of 0 or more, if the first through hole defines the track @, as described above, patterning can be performed in a place without a step. Therefore, the track width accuracy is improved.

In this way, in the case of a two-layer coil, the first. Rather than continuously etching the second groove, the formation of the coil insulating film and the groove formation are repeated. Moreover, the groove formation can be performed simultaneously with other processes, so the number of processes does not increase (the total gear lug depth Highly accurate track width control is possible over the entire range.

Next, another embodiment will be explained with reference to FIG. This figure shows the sliding surface, and the same parts as in Figure 3 are shown with the same symbols. This embodiment is applied to a structure in which the lower magnetic core 2 is formed to the track width dimension and is embedded with an insulating material 9. The insulating film, which is thinner than the conventional one, is etched to align the through holes in the lower core. Therefore, alignment accuracy can be significantly improved compared to conventional methods. That is, the track deviation between the upper core and the lower core can be made smaller than before, and the track width can be controlled with high precision. In addition, the second through hole 7b is formed so that its end is located in the tapered portion of the first through hole 7a, thereby reducing magnetic flux leakage at the upper and lower core ends.
It also has the effect of improving performance. At this time, if the taper angle of the second through hole is too large, the tapered end in the magnetic path direction is fc, as in the embodiment of FIG. By forming the tapered portions of the second through holes to be separated, deterioration of the magnetic film characteristics can be suppressed. That is, according to the first embodiment, the ω through-hole taper angle in the trunk width direction can be made larger than the taper angle in the magnetic path length direction. As is clear from the reference numerals in FIG. 4, this example is manufactured by the manufacturing method explained in FIG. As mentioned above, even if the first groove and the second groove are formed continuously after the last coil insulating layer is formed, the taper angle in the track width direction is larger than the αnotaver angle in the magnetic path direction. You can do it.

The present invention has been described above using examples, but the first point is the main point of the invention. It goes without saying that there are many possible variations on the structure of the head outside the fish body, where one through hole is created using two grooves as shown in @2. Also, the shape of the through hole itself is determined by the two grooves.9. [Effects of the Invention] According to the present invention, a groove formed by a through hole may be added to make the etching process easier by adding a groove that is larger than the through hole. has a rectangular shape, making it possible to create a thin film magnetic head with a track width of - at any point in the gap depth direction. Since the track width can be determined using a thinner film than before, the track width accuracy itself can be improved.

[Brief explanation of the drawing]

1(a) and 2) are a perspective view and a sectional view of a thin film magnetic head showing an embodiment of the present invention, and FIG. 2 is an enlarged view of the gap forming part before forming the upper core of the thin film magnetic head of FIG. 1. Perspective view,! 3(a) to 3(i) are process sectional views explaining the manufacturing method of the thin film magnetic head of the present invention, the fourth factor is a front view showing the sliding surface of the thin film magnetic head showing another embodiment, and the fifth factor is Figure (a
) and (b) are a perspective view of a conventional thin film magnetic head and a plan view of a gap forming part. 1... Board 2... Lower magnetic core 3...
-Gap material 4...Coil insulating film 41, 42.
45.--Respectively 1st. Second. $5 Coil insulating layer 5...Coil conductor 6...Upper magnetic core 7...
・Through hole 71...first etching groove 72・
・・Second Etching Groove Agent Patent Attorney Masao Ogawa 13 Ro33 Concave J3 + Figure Era times (α)

Claims (1)

[Claims] 1. A lower magnetic core, a gap material, a coil conductor, on a substrate,
In a thin film magnetic head formed by laminating a coil insulating film and an upper magnetic core, the coil insulating film is formed such that the ridgelines of each groove are substantially perpendicular to each other in a substantially straight region, and the width in the track width direction is equal to the track width. A thin film magnetic head characterized in that a gap forming surface is a through hole in a coil insulating film formed by an overlapping portion of at least two grooves, a first rectangular groove and a second rectangular groove whose width is larger than the track width. 2. A thin film magnetic head in which the lower magnetic core has a track width dimension at least on the gap forming surface,
The position of the through hole in the coil insulating film formed by the at least two grooves substantially coincides with the surface of the lower magnetic core, and
2. The thin film magnetic head according to claim 1, wherein the tapered lower end of the second groove in the track width direction is located at the tapered portion of the first groove.