JPS6376105A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To contrive to reduce variations in head characteristics of head chips on a wafer by making the member to be flattened thicker in the front connection part than in the other parts and using the face of that member being made thin with a gentle slope toward the rear connection part as the bottom face of the lower core. CONSTITUTION:In forming the member 2 to be made flat and applying photo resist to the member 2 by rotation, the film thickness of the resist differs from a length of a base groove 4, a front connection width and width of a rear connection part 6. The difference is utilized to form the member 2 to be made flat so that the thickness is made thicker at the front connection part and thin with a gentle slope in the rear connection direction. That is, in applying the resist by rotation to the member 2, the depth of the resist groove approaches depending on the depth of the base groove 4, groove length and width to a prescribed value. Thus, the variance in the shape of the lower core 3 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head in which a lower core is embedded in a groove of a substrate, in which the bottom surface of the lower core is flattened.

[Conventional technology]

One of the shape factors that determines the head characteristics of a thin film magnetic head is the distance between the upper core and the lower core. If this interval is narrow, magnetic flux leakage between the upper and lower cores will increase, and recording and reproducing efficiency will deteriorate. As a countermeasure to this problem, measures are taken to increase the non-magnetic development between the cores in order to widen the gap between the upper and lower cores. However, if the above measures are taken on the same substrate surface, patterning of the upper core must be performed with large steps.

For this reason, it was not possible to achieve the ideal form of patterning with a low level difference during high-precision patterning, and there was a problem that the ideal of head failure and the ideal of patterning were contradictory. In order to improve In addition to reducing the level difference, the distance between the upper and lower cores has been increased. An example of a thin film magnetic head of this type is the one described in Japanese Patent Application Laid-Open No. 57-189321.

However, in the conventional example described above, if the surface roughness of the non-magnetic substrate or the roughness of the groove bottom of the recess is large, the lower core forming surface must be flattened, but at this time, the lower core thickness may fluctuate. , which leads to variations in recording and reproducing efficiency,
This point was not considered.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, it is necessary to flatten the lower core forming surface, which causes the lower core thickness to fluctuate, resulting in variations in recording/reproducing efficiency and head sliding properties.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thin film magnetic helium rad system that reduces variations in lower core thickness, particularly at the front connection.

[Means for solving problems]

The above purpose is to reduce the thickness of the resist film by forming an anthoptic ffl material in a substrate groove formed on a non-magnetic substrate or the like in order to reduce the unevenness t on the core forming surface, and then spin-coating a photoresist as a flattening material. Differences in film thickness occur due to the relationship between substrate groove depth, substrate groove length, front connection part width, and rear connection part width, and by using this difference, the thickness of the material to be planarized is thicker at the front connection part, and the thickness of the material to be planarized is thicker at the front connection part, and the thickness of the material to be planarized is thicker at the front connection part, and the thickness of the material to be planarized is thicker at the front connection part, and the thickness of the material to be planarized is thicker at the front connection part. This is achieved by making it thinner with a gentle slope in the direction.

[Effect]

Photoresist as a planarizing material) E When spin coating is performed, the resist groove depth approaches a constant value depending on the substrate groove depth, groove length, and groove width, so it is possible to reduce variations in the shape of the lower core.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (α) is a plan view of the lower core on the thin film magnetic head substrate according to the present invention, and FIG. 3 is a lower core, 4 is a substrate groove, 5 is a magnetic gap portion, 6 is a rear connection portion, and 7 is a lower core forming surface.

In the figure, a lower core 3 is attached to a ceramic non-magnetic substrate 1.
The substrate groove 4 is shaped so that the 70-pin connecting portions of the A and B2 hent chips face each other and are connected.

Front connection part length t is approximately 500 μm 1 Core total length is approximately 11000 μm 1 Front core groove width Fw is approximately 30 μm 1
The rear groove width Rw is approximately 280 μm, and the substrate groove depth tR is approximately 20 μm.

A sputtered Cr film with a thickness of 10 .mu.m was used as the material 2 to be planarized in the substrate groove 4 (bottom surface unevenness: about 3 .mu.m P-P) formed on the substrate 1 by ion etching. After spin-coating a photoresist on the Cr surface to a thickness of approximately 3.5 μm on a flat surface, Cr was etched using an ion etching method.
The above resist surface 3 was transferred onto the surface to form a lower core forming surface 7 (bottom surface roughness: approximately 0.5 μm p-p). As a result, the front connection part:) 7 Thickness ty is approximately 15 μm, +)
The core thickness tR of the connecting portion is approximately 20 μm, which is a preferable shape from the viewpoint of the magnetic flux throttling effect. Note that Tw is the magnetic gap width.

According to the above embodiment, the gap depth! The variation in core thickness within qd- is reduced, resulting in a head with stable recording/reproducing efficiency and good head sliding properties, and the number of chip divisions is reduced by arranging the rad chip to face -2. In addition, it is possible to shorten head manufacturing time and increase the number of head chips on the same Unibar. In addition, a signal is applied to one of the signal coils connected in a wafer state,
By detecting the output from the other signal coil, it is possible to determine whether the head characteristics are good or bad.

Figure 2 is a characteristic diagram when photoresist is spin-coated, and there is a relationship between the resist groove depth and substrate groove width of the substrate groove.
As the groove width increases, the resist groove depth increases, and when a certain groove length L (width W) is reached, the resist groove depth tl is saturated near the substrate groove depth to. However, even when the substrate groove length is longer than L, the resist groove depth tl does not match the substrate groove depth to in places where the substrate groove width is narrower than W, and the resist groove depth corresponds to the substrate groove width W. I get saturated with it.

For example, even under the same condition that the groove depth to is approximately 20 μm, if the front connection portion groove width is 30 μm, the rear connection portion groove width is approximately 280 μm, and both groove lengths are 250 μm or more, the front resist groove depth is The depth of the rear resist groove is about 13 μm, and the depth is saturated at about 20 μm.

The groove length between the groove width W and the groove depth to is approximately 12t.
By setting the resist groove depth tl within the groove to be 0 to 15to or more, the resist groove depth tl in the groove is saturated at a value corresponding to the groove width W, and fluctuations are reduced.

By making the lower core shape and dimensions as shown in Figure 1 (α), the front connection part length L is equal to the length and width of the substrate groove in Figure 2).
The required groove length is approximately 250μ from the relationship between
Since it is sufficiently longer than m, the cross-sectional shape of the lower core of the front connection part shown in FIG. The upper core 11 is a protective film 0 The figure shows a magnetic gap part 5 and a rear connection part 6 on the lower core 3.
After forming the insulating material 9, the signal coil 8, the upper core 10
This is a head chip in which a protective film 112 and a protective film 112 are sequentially formed and patterned.

The cross-sectional shape of the lower core B is the shape when the material 2 to be flattened formed on the non-magnetic substrate is flattened with a flattening material, that is, the thickness of the material 2 to be flattened in the rear connection part 6 is a gentle slope. The thickness of the material 2 to be flattened changes in the direction of the front connection part (magnetic gap part 5), and the thickness of the material 2 to be flattened is thicker in the front connection part than the part where the fill 8 is formed, and the thickness of the material to be flattened is thicker in the front connection part and the part where the coil 8 is formed. The surface where the thickness of the material to be flattened 2 becomes thinner in the direction of the forming portion of the fill 8 with a gentle slope between the two surfaces becomes the bottom surface of the lower core.

4(α) and (b) are other embodiments according to the present invention? A plan view and a cross-sectional view showing the front connection part substrate groove length t.
After forming a substrate groove of approximately 300 μm, which is 15tR of the front connection substrate groove depth tH (approximately 20 μrrL), the core forming surface 7 was flattened in the same manner as in the above embodiment, and when the lower core 32 was formed, magnetic A hent tip was obtained in which the thickness of the lower core at the portion where the gap portion 5 was formed was stable.

〔Effect of the invention〕

As explained above, according to the present invention, in a lower core embedded thin film magnetic head, it is possible to reduce the variation P of the lower core thickness at the magnetic gap portion, and therefore it is possible to reduce the variation in head characteristics between hentochonbs on a wafer. We can solve the problems of the above conventional technology and provide a thin film magnetic head with new and excellent functions.

[Brief explanation of the drawing]

Figure 1 (cL) is a plan view of the lower core on the thin film magnetic head substrate, Figure 1 (b) is a cross-sectional view of the same, Figure 2 is a characteristic diagram when photoresist is spin coated, and Figure 5 is a cross section of the head. figure,
FIG. 4 (α) and ('') are a plan view and a cross-sectional view showing another embodiment 2. 0 1... Head substrate, 2... Material to be flattened, 3
... lower core, 4 ... substrate groove, 5 ... magnetic gap section, 6 ... rear connection section, 7 ... lower core forming surface. Figure 1 Figure 2 Figure 0 /ρθ 200 300 ヂ0
0 groove grilled pattern mu (f”) Figure 3 Otokozu

Claims (1)

[Claims] 1. A material to be planarized is formed in a groove portion patterned on a non-magnetic substrate or a non-magnetic thin film formed on the substrate, and the surface of the material to be planarized is flattened with the planarizing material at the front and rear connection portions. In a thin-film magnetic head having a lower core forming surface including: A thin film magnetic head characterized in that it is configured such that the bottom surface of the lower core is the bottom surface of the lower core.