JPS5916123A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To lower the density of lead wires to convert a thin film magnetic head to high density, by using a shield part of a magnetoresistance thin film as a common wiring. CONSTITUTION:A lead wire 8b connected to the center part of a magnetoresistance element 1 is connected to a shield thin film 5 through a hole 10 provided in a nonmagnetic insulator layer 4, and the shield thin film 5 is taken out as a common lead wire to the outside. By this constitution, three lead wires required for one track in the conventional constitution are reduced two, and track pitches are made close when the wire width and intervals of wires are the same as conventional track pitch. When track pitches are the same as conventional one, intervals of wires are made wider, and therefore, short-circuits between wires due to dust at a production time of a head are reduced to improve the yield.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin film magnetic head, and particularly to a magnetoresistive thin film magnetic head (hereinafter referred to as a magnetoresistive head) capable of high track density reproduction.

Thin-film magnetic heads have come to be used as a means for recording and reproducing PCM music signals on magnetic tapes and the like because they enable higher track density. In particular, as a reproducing head, a magnetoresistive head that utilizes the magnetoresistive effect of a ferromagnetic thin film is used because the reproducing output does not depend on the speed of the recording medium. This magnetoresistive head has a simple structure and has the advantage of being easy to increase track density. However, the signal line section has a longer route than the head element section, so it is difficult to increase the track density. It is thought that there are a number of factors that limit the track density, and countermeasures have been taken to counter this, such as using two layers of wiring with an insulating film interposed therebetween.

FIG. 1 shows the structure of a conventionally used magnetoresistive head. The figure (-) is a front view, and the figure (b) is a side view. In the figure, 1 is a ferromagnetic thin film such as Ni-Fe,
It has anisotropy in the longitudinal direction, and when there is no signal, Ti
Due to the magnetic field created by the currents 7a and 7b flowing through the conductive thin film 2 for bias application, the direction of magnetization is directed at approximately 45 degrees to the direction of the current. 3,
Reference numeral 5 denotes a shield made of a ferromagnetic material to improve the wavelength characteristics of the reproduction voltage. (not shown). The signal detection current is applied to lead wires 6a and 5Q made of a thin gold film or the like with the same polarity, and flows out from the grounded lead wire 6b.

When a signal magnetic field is applied from the outside, the angle θ between the magnetization of the ferromagnetic thin film 1 and the current changes, and the specific resistance of the ferromagnetic thin film 1 changes as shown by ρ=ρO+ΔρmaxCO52θ, and the signal magnetic field changes. can detect changes in ρ. is the specific resistance when no magnetic field is applied.

The reason why current flows in opposite directions from the lead wires 6a and 6c is to cancel out second harmonic distortion caused by the square characteristic of magnetic resistance change. However, each track requires three lead wires, for example, the track pitch is 100 μm.
m, if track width is 80 μm, lead wire width 2Q
It becomes necessary to perform extremely high-density wiring with a pitch of 10 .mu.m2, and the track density is more limited by the wiring portion than by the head portion. Note that 4 is a nonmagnetic insulating layer, and 9 is a support substrate.

The present invention aims to reduce the density of lead wires by using the shield portion of the magnetoresistive thin film as a common wiring, thereby making it possible to increase the density and increase the yield when manufacturing thin film heads. .

Embodiments of the present invention will be described using the drawings.

Embodiment 1 FIG. 2(a) is a front view of a thin film magnetic head of the present invention, and FIG. 2(b) is a side view. The lead wire 8b connected to the center of the magnetoresistive element 1 is connected to the shield thin film 5 (not shown in FIG. 2(a)) through a hole 10 made in the nonmagnetic insulating layer 4, as shown in the figure. The shield thin film 5 is used as a common lead wire and is taken out to the outside.

Note that 3 is a shield plate and 9 is a support substrate.

According to this structure, the number of lead wires required per track is two instead of the conventional three, and the track pitch can be reduced with the same line and line spacing as in the past. Also,
If the track pitch is the same as in the past, the line spacing can be widened, so short circuits between lines due to dents during head manufacturing can be reduced, and yield can be improved.

Embodiment 2 FIG. 3(a) is a front view of another embodiment of the thin film magnetic head of the present invention, and FIG. 3(b) is a side view. Magnetoresistive element ・
The lead wire 10b connected to one end of the substrate 1 passes through a hole made in the non-magnetic insulating layer 4 as shown in the figure.
It is connected to a shield film 11 formed on 2, and taken out to the outside using the shield film 11 as a common lead wire.

In the head of this shape, there are two lead wires for each track, and compared to the head of Example 1, the number of wires is smaller and it is easier to increase the density. However, as shown in this example, the shielding film is If it is used as one helix of the lead wire, there will be one lead wire for each track, making it possible to achieve even higher density.

As shown in the embodiments above, according to the present invention, the number of lead wires can be reduced by using the shield film as a part of the wiring, so that when the track pitch is shortened, adjacent lead wires become close to each other. Problems such as insulation defects caused by this can be greatly reduced. There is still no problem of poor insulation between lines, and there is less increase in the number of steps compared to the case where the wiring is in two layers.

[Brief explanation of drawings]

FIG. 1(a) is a front view showing a conventional example of a thin film magnetic head;
FIG. 2(b) is a sectional view of the same, and FIG. 2(a) is the first embodiment of the present invention.
3(-) is a front view of the thin film magnetic head of the embodiment shown in FIG. 2, and FIG. 3(b) is a sectional view thereof. . 1... Magnetoresistive element element, 4... Nonmagnetic insulator layer, 5... Shield thin film, 8.8a
, sb, 8c. 10.10a, 10b, 10cm---Lead wire, 1
1... Shield thin film. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure (4) Δa Figure 2 ((1) Mu

Claims (1)

[Claims] A ferromagnetic shield member is installed on both sides of a ferromagnetic thin film having a magnetoresistive effect via a non-magnetic insulating material, and one of the signal detection terminals is connected to at least one of the shield members. Features a thin film magnetic head.