JPH0668430A - Magneto-resistance effect type read converter - Google Patents

Abstract

PURPOSE:To obtain a magneto-resistance effect type read converter capable of accurately regulating the effective width of an MR element without deteriorating the characteristic of the MR element and adaptive for the realization of a narrow track and high recording density. CONSTITUTION:This converter is provided with the MR element 1, a switching bias layer 2 provided on the MR element in which the film thickness of the first part coming in contact with the active area 5 of the MR element functioning for the detection of a magnetic field is formed thinner than that of the second part of the switching bias layer 2 coming into contact with the passive area at both sides of the active area 5 and in the film thickness less than a prescribed value decided in advance, and a pair of separated conductors 3 whose edge parts are arranged on the second part of the switching bias layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive read converter, and more particularly to a magnetoresistive read converter using a ferromagnetic thin film.

[0002]

2. Description of the Related Art A magnetoresistive read transducer, that is, an MR transducer or a sensor (hereinafter represented by an MR transducer) can read an information signal recorded on a magnetic recording medium at a high recording density. Conventionally known as a magnetic transducer. MR transducers use the fact that the resistance of an MR element made of a material exhibiting a magnetoresistive effect changes as a function of the amount and direction of magnetic flux to detect magnetic field signals.

Various MR elements have been developed and these have met the requirements set in the past. However,
In the situation where the recording track width is becoming narrower and the linear recording density along the track is becoming higher due to the higher recording density, the conventional technology is suitable for a narrow track width and a high recording density. Forming MR transducers has become difficult.

Japanese Patent Laid-Open No. 57-198528 discloses an M type in which an MR element is separated from a bias layer by an insulating layer.
An R head is disclosed. In this case, the track width is determined by the distance between the pair of conductor patterns provided for detecting the signal of the head.

A conventional MR converter will be described with reference to FIGS. 3 and 4. FIG. 3 is a plan view of a typical MR converter in which the effective width of the MR element, that is, the active region is defined by the distance between a pair of conductors, and FIG. 4 is a sectional view taken along line AA.

The MR converter has an MR element 1 formed on a suitable substrate (not shown). An antiferromagnetic layer (hereinafter referred to as an exchange bias layer) 2 utilizing an antiferromagnetic exchange coupling force for applying a bias magnetic field for improving the magnetoresistive conversion efficiency is provided on the MR element 1. The MR converter also includes a non-magnetic layer, which is omitted here. The active region 5 of the MR element 1 is a region not covered with the conductor 3. The active area 5 functions to produce an output signal in response to the magnetic field. Since the passive region 4 of the MR element 1 covered with the conductor 3 is electrically short-circuited by the conductor 3, it is useless from the viewpoint of the magnetoresistive effect. In the case of this MR converter, the width accuracy of the active region 5,
That is, the precision of the effective width of the MR converter depends on the placement precision of the conductor 3. The method of forming the conductor 3 is as follows.
After attaching a conductor so as to cover the entire MR element 1,
As shown in FIGS. 3 and 4, the conductor 3 in this portion is removed by etching so as to leave only a portion having a width corresponding to the active region 5. As a method of etching the conductor, for example, in the case of the MR converter shown in FIGS. 3 and 4, chemical etching is performed.

[0007]

In the above-mentioned conventional magnetoresistive read transducer, the conductor 3 attached to the active region is removed by chemical etching. Since the etching pattern accuracy of chemical etching is generally inferior to that of dry etching, the conventional magnetoresistive effect reading converter in which the conductor spacing is defined by chemical etching is not suitable for narrower tracks and higher recording densities. There is a problem that it is difficult. That is,
As the track width becomes narrower, it becomes difficult to accurately arrange the pair of conductor patterns at a predetermined interval, and thus it becomes difficult to accurately define the effective width of the MR element.

As a method for solving this problem, it is conceivable to process the conductor by dry etching, but since dry etching generally has low selectivity, the active region of the MR element is etched during etching of the conductor. The conversion efficiency is likely to deteriorate. Therefore, a method of ending the etching of the conductor before the active region was etched was tried, but the conductor remained on the active region, resulting in a decrease in MR conversion efficiency.

An object of the present invention is to determine the effective width of the MR element as M
It is an object of the present invention to provide a magnetoresistive effect read converter which can be accurately specified without deteriorating R element characteristics and can be adapted to narrower tracks and higher recording density.

[0010]

A magnetoresistive effect read converter according to the present invention comprises a magnetoresistive effect element and an antiferromagnetic element for providing an exchange coupling bias for improving the magnetoresistive conversion efficiency provided on the magnetoresistive effect element. The film thickness of the layer and the first portion of the antiferromagnetic layer for applying the exchange coupling bias for improving the magnetoresistive conversion efficiency, which is in contact with the first portion which is the active region of the magnetoresistive effect element to act for detecting the magnetic field, It is thinner than the film thickness of the second portion of the exchange-coupling bias applying antiferromagnetic layer for improving the magnetoresistance conversion efficiency, which is in contact with the second portions which are the passive regions on both sides of the first portion of the magnetoresistive effect element. A pair of separated conductive layers having a film thickness equal to or less than a predetermined fixed value and having an edge portion arranged on the second portion of the exchange-coupling bias applying antiferromagnetic layer for improving the magnetoresistance conversion efficiency. Is composed of having a body and .

[0011]

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

FIG. 1 is a sectional view showing an embodiment of the magnetoresistive reading converter of the present invention, and FIG. 2 is a sectional view of this embodiment before a conductor is provided.

The feature of this embodiment is that the edge of the conductor 3 is provided so as to be in contact with the exchange bias layer 2. Therefore, the active area 5 of the MR element is defined by the exchange bias layer spacing, not the conductor 3 spacing. During the detection of the magnetic field, when a current is supplied to the conductor 3, only a change in resistance of the active region 5 in response to the magnetic field causes a change in current.

The exchange bias layer 2 is, for example, FeM.
An antiferromagnetic material such as n was used. As a method of defining the exchange bias layer interval, first, a ferromagnetic soft magnetic thin film such as NiFe is deposited by a vapor deposition method to a thickness of about 400 angstroms while a magnetic field is being applied, and the exchange bias layer is sputtered so as to cover the entire MR element 1 formed. To a thickness of about 500 Å. The sputtering conditions are Ar gas pressure: 5 mm torr and RF power: 600 W.

Next, as shown in FIG. 2, only the portion of the active region 5 of the MR element 1 having a predetermined width is removed by etching. The exchange bias layer 2 in the region to be removed at this time is not completely etched but is etched so as to leave the exchange bias layer at a maximum of about 100 Å so that the MR element active region 5 is not etched.

As the etching method, ion etching using Ar gas, which is widely used as the current etching method for the exchange bias layer 2, was used, and the etching amount was controlled by the etching rate and the etching time. Etching conditions are Ar gas pressure: ⁴ × 10 ⁻⁴
Torr and acceleration voltage: 500V. In the case of this method, etching can be performed with higher accuracy than chemical etching, and the width defining accuracy of the active region 5 of the MR converter is improved.

FIG. 5 shows the dependence of the bias magnetic field H _B due to exchange coupling on the thickness of the exchange bias layer. From FIG. 5, when the thickness of the exchange bias layer is 100 Å or less, the bias magnetic field is hardly applied, which is substantially the same as the case where the exchange bias layer 2 is not provided. Based on this result, it was found that the MR conversion efficiency when the exchange bias layer 2 is etched to leave about 100 angstroms as described above is no different from that when the exchange bias layer is completely removed. .

After forming the exchange bias layer 2, the conductor 3 is attached so as to cover the exchange bias layer 2 and the entire MR element 1 so that the edges of the conductor 3 are formed on the exchange bias layer 2. To do. As the conductor 3, for example, Au or the like is deposited by a vapor deposition method to a thickness of about 2500 Å. At this time, the etching of the conductor 3 no longer defines the active region of the MR element.
Conventional chemical etching methods are sufficient. Conductor 3
When Au is used as the material, it can be easily etched with an aqueous solution of iodine and potassium iodide.

[0019]

As described above, the magnetoresistive effect read converter of the present invention uses the conventional manufacturing method.
The width of the active region of the R element can be markedly easily and accurately defined without deteriorating the characteristics of the MR element, and has an effect that it can be adapted to a narrow track and a high recording density.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a magnetoresistive effect read converter of the present invention.

FIG. 2 is a cross-sectional view of this example before a conductor is provided.

FIG. 3 is a plan view showing a conventional magnetoresistive effect read transducer.

FIG. 4 is a cross-sectional view showing a conventional magnetoresistive effect read transducer.

FIG. 5 is a characteristic diagram showing the dependence of the exchange bias magnetic field H _{B on} the exchange bias layer thickness.

[Explanation of symbols]

 1 MR element 2 Exchange bias layer 3 Conductor 4 Passive region 5 Active region

Claims (1)

[Claims] 1. A magnetoresistive effect element, an anti-ferromagnetic layer for applying an exchange coupling bias for improving magnetoresistive conversion efficiency, which is provided on the magnetoresistive effect element, and an active part of the magnetoresistive effect element, which acts for detecting a magnetic field. The film thickness of the first portion of the exchange coupling bias applying antiferromagnetic layer for improving the magnetoresistive conversion efficiency that is in contact with the first portion, which is a region, is the passive region on both sides of the first portion of the magnetoresistive effect element. Which is thinner than the thickness of the second portion of the exchange-coupling bias applying antiferromagnetic layer for improving the magnetoresistive conversion efficiency which is in contact with the second portion of A magnetoresistive effect read converter comprising: a pair of separated conductors whose edges are arranged on a second portion of an exchange coupling bias applying antiferromagnetic layer for improving magnetoresistance conversion efficiency. .