JPH0346107A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To prevent the electrification of magnetic layers by providing a terminal for grounding on the lower magnetic layer. CONSTITUTION:The magnetic head has the lower magnetic layer 2 of a nearly rectangular plane disposed on a substrate 1. A gap for transmitting and receiving signals to and from a recording medium is disposed in the front part between the layer 2 and the upper magnetic layer 6. A coil part 4 is disposed behind the gap between the two magnetic layers as well apart insulating layers 3, 5. Terminal parts 4a, 4b to constitute a juncture between this coil part 4 and an external wiring are disposed behind the coil 4. The part of the intermediate coil winging tends to have the width larger than in the other parts in order to assure the larger number of turns of the coil as far as possible. The part near the rear part disposed with the terminal parts 4a, 4b has a relative margin in disposition. The grounding terminal 8 is disposed between these terminals 4a and 4b and the need for enlarging the lower magnetic layer for the purpose of disposing this grounding terminal 8 is eliminated. The electrification of the magnetic layers 2, 6 is prevented by this grounding terminal 8.

Description

[Detailed Description of the Invention] [Prior Art] In recent years, with the progress of increasing the density of magnetic recording, the recording wavelength and recording track width have been reduced, and the frequency of recording and reproduction signals has also been increasing. Thin-film magnetic heads, which are smaller and have better high-frequency characteristics than conventional magnetic heads using bulk magnetic materials, are increasingly being used.

In a thin film magnetic head, the bottom magnetic layer is on the substrate.

Thin films serving as a coil conductor layer, an insulating layer, a gap layer, and an upper magnetic layer are formed. The thickness of these films is, for example, on the order of .mu.m, and thinner films are required to be made thinner and thinner in order to improve the recording density mentioned above.

[Problems to be Solved by the Invention] When such a thin film head is incorporated into a system and used, a part of the connection terminal leading to the coil may sometimes be grounded. In this case, a problem occurred in that static electricity stored in the medium tends to flow into the coil through the upper or lower magnetic pole, resulting in part of the insulating layer between the coil and the magnetic pole being destroyed.

An object of the present invention is to provide a highly reliable thin-film magnetic head in general, in which each layer is increasingly thinned.

[Means for Solving the Problems] The object of the present invention is to provide at least a lower magnetic layer 2 on a substrate.
This is achieved by a thin film magnetic head comprising a coil conductor layer, an insulating layer, a gap layer and an upper magnetic layer, characterized in that a ground terminal is disposed on the lower magnetic layer. In this case, it is preferable to use a part of the lower magnetic layer as a ground terminal.

The knowledge of the present invention was discovered during an experiment, which is thought to be due to the thinning of one layer of the insulating layer of a thin-film magnetic head, which caused dielectric breakdown of the insulating layer between the upper magnetic film and the coil. Based on that.

In the past, it has been theoretically considered to provide grounding to magnetic heads, but this is partly due to the narrow dimensions of such thin film heads.

Furthermore, even if a part of the magnetic head were charged at one moment, it was thought that the next moment the discharge would take place through some path, so no grounding terminal was placed on the thin-film magnetic head at all. It wasn't.

However, in order to meet the above-mentioned demand for thinner films, the active insulating layer must also be made thinner.2 For example, due to sliding contact with the recording medium, charges on the charged magnetic layer are discharged to the nearest coil conductor layer, etc. However, in this case, it is expected that dielectric breakdown of the insulating layer will occur.

In the present invention, since the ground terminal is provided on the lower magnetic layer, charging of the upper magnetic layer can be prevented by connecting this to a predetermined ground electrode via a lead wire or the like.

Furthermore, the lower magnetic layer must be made larger than the upper magnetic layer in order to provide space for this ground terminal. The ground terminal is formed by etching a part of the insulating layer formed on the bottom magnetic layer.
It is preferable to expose the lower magnetic layer by removing it by cleaning, and to form the layer using a part of the exposed lower magnetic layer.

[Effect] By providing a ground terminal on the lower magnetic layer.

This can be electrically connected to a predetermined ground electrode through a connecting means such as a lead wire, and the 1js charge charged on the magnetic layer can be discharged, thereby suppressing the increase in the potential of the magnetic layer.

[Example] The present invention will be described with reference to the drawings. FIG. 1 is a plan view showing the main structure of a thin film magnetic head according to an embodiment of the present invention, with the substrate 1 removed. Figure 2(a)
, (b) are structural sectional views of the thin film magnetic head taken along the lines AA' and B-8' in FIG. 1, respectively.

The thin film magnetic head of this embodiment includes a substrate l made of magnetic or non-magnetic material, a lower magnetic layer 2 formed on the substrate l from a magnetic material such as amorphous, sendust, or permalloy, and a lower magnetic layer 2 formed on the lower magnetic layer 2. A first insulating layer 3 made of an insulating material such as 8102, a conductor layer 4 made of a conductive material such as Cu or Cu alloy on this insulating layer 3, and a first insulating layer 3 made of an insulating material such as 810. A second insulating layer 5 made of an insulating material such as, a layer 9 extending from the center of the spiral coil formed thereon, and a second insulating layer 5 made of the same magnetic material as the lower magnetic layer and cooperating with the lower magnetic layer. an upper magnetic layer 6 forming a magnetic path; a gap layer 7 formed between the upper and lower magnetic layers and made of an insulating material; and two external terminals for connecting the conductor layer and external lead wires. 4
a, 4b, and a grounding terminal 8 arranged between these,
It basically consists of the following, and a protective layer is finally provided at required locations as necessary.

The ground terminal 8 is connected to an insulating layer (
3) It is formed by removing a part of (4) into a desired shape by ion milling or the like. Therefore, the lower magnetic layer (2) is exposed on the surface of the grounding terminal.

The external terminals 4a, 4b and the ground terminal 8 are each bonded to an external lead wire, and the other ends of the lead wires are connected to a predetermined external circuit and a ground electrode, respectively. The length of the lower magnetic layer 2 is longer than the length of the upper magnetic layer 6 by approximately the length of the portion where the three terminal portions are arranged. Further, the upper magnetic film and the lower magnetic film have a bridge portion that is magnetically and electrically conductive at the center of the coil.

As shown in FIGS. 1 and 2, the magnetic head according to this embodiment has a lower magnetic layer 2 having a substantially rectangular planar shape disposed on a substrate 1, and this lower magnetic layer 2 and an upper magnetic layer 6. A gap for transmitting and receiving signals to and from the recording medium is disposed at the front between the layers, and a coil section 4 is disposed at the rear between the two magnetic layers with an insulating layer 3.5 in between. Terminal portions 4a and 4b, which serve as connection portions between the coil portion 4 and external wiring, are arranged at the rear of the coil 4. The middle coil winding portion tends to be wider than other portions in order to ensure as many turns as possible in the coil. Therefore, as can be easily seen from the figure, there is relatively more room in the rear area where the terminal portions 4a, 4b are arranged. In this embodiment, the ground terminal 8
Since the ground terminal is placed between the terminals 4a and 4b, there is no need to make the lower magnetic layer large for the arrangement of the ground terminal.

In this example, an insulating layer is not interposed between the upper magnetic layer 6 and the lower magnetic layer 2 and between the lower magnetic layer 2 and the substrate l, but an insulating material is interposed between either of these layers. In such a case, it is preferable to provide a conductive portion for these or to establish conduction through a separate conductive means.

[Effects of the Invention] In the configuration of the present invention, by providing the grounding terminal on the lower magnetic layer, it becomes possible to connect this to a suitable grounding electrode via a lead wire or the like.

It is possible to prevent the magnetic layer from being charged. Preferably, by making the upper magnetic layer and the lower magnetic layer electrically conductive, this effect can be better achieved and a highly reliable thin-film magnetic head can be obtained.

Although the present invention has been described in the case of a single-layer coil, it goes without saying that the same effect can be achieved in a multi-layer coil having two or more layers. Furthermore, it goes without saying that similar effects can be achieved in a multi-channel thin film head in which a large number of heads are lined up.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing the structure of a thin film magnetic head according to an embodiment of the present invention, excluding the substrate. 2(a) and 2(b) are structural sectional views taken along the lines AA' and BB' of the thin film magnetic head shown in FIG. 1, respectively. Explanation of symbols 1...Substrate 2...Lower magnetic layer 3.5
...Insulating layer 4...Conductor layer 4a, 4b...
External terminal 7...Gap layer 6...Top magnetic layer 8...Ground terminal

Claims (1)

[Claims] At least a lower magnetic layer, a coil conductor layer, an insulating layer,
1. A thin film magnetic head comprising a gap layer and an upper magnetic layer, characterized in that a ground terminal is disposed on the lower magnetic layer.