JPH1145416A - Magnetoresistance effect element and thin film magnetic head equipped with that element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetoresistance effect layer in which the length of a tapered part formed on the end edge part of an opposite side to the surface facing to a magnetic medium on a magnetoresistance effect layer is properly stipulated by setting the conditions of ion milling so that the ratio of the length of the tapered part in the perpendicular direction to the track width direction to the length from the magnetoresistance effect layer to the end edge is a specified value or smaller. SOLUTION: A magnetoresistance effect (MR) layer 13 formed in a shield gap layer is formed as a strip shape in which a ferromagnetic body or a spin- bulb multilayered structure is extended in the track width direction. A tapered part 13a is formed on the end edge of the opposite side to a floating face 18 by ion milling treatment in the case of patterning the MR layer 13. The length L of the tapered part 13a is made so as to be <1/5 of the height hMR of the MR by controlling the conditions of ion milling. Thereby, decrease in an MR reproducing output and increase in the resistance of an MR element can be prevented and further, decrease in the presumed accuracy of the life of the MR element can be also prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive (MR) element for reading information recorded on a magnetic medium such as a magnetic disk and a thin film magnetic head provided with the MR element.

[0002]

2. Description of the Related Art Generally, an MR layer in an MR type thin film magnetic head (hereinafter referred to as an MR head) is formed by laminating a ferromagnetic layer such as NiFe on a lower shield layer, and performing ion milling from a mask such as a patterned resist. It is formed by applying.

[0003]

As described above, when the MR layer is patterned by ion milling, the edge portion on the side opposite to the air bearing surface (ABS) facing the magnetic medium does not end at a right angle but is inclined. End, a tapered portion is formed. If the length L (length in the direction perpendicular to the track width direction) of the tapered portion is increased, the edge of the MR layer opposite to the ABS cannot be accurately defined, and the height h _MR (ABS Length from the edge of the to the opposite edge,
(Hereinafter referred to as MR height) cannot be accurately defined.
Further, even if the MR height h _MR can be specified, if the length L of the tapered portion is larger than this MR height h _MR ,
The reproduction output of the MR head decreases, the resistance as the MR element increases, and the accuracy of estimating the life due to electromigration decreases. In particular, when the recording density increases and the track width decreases,
Accordingly, it is necessary to further reduce the size (in order to keep the aspect ratio of the rectangular shape of the MR layer constant), so that the increase in the length L of the tapered portion becomes a serious problem.

Accordingly, it is an object of the present invention to provide an MR head in which the length of the tapered portion of the MR layer is appropriately defined.

[0005]

According to the present invention, there is provided a magnetic head having a strip-shaped MR layer extending in a track width direction.
In the R element, the length (L) of the taper portion formed at the edge of the MR layer opposite to the surface facing the magnetic medium in the direction perpendicular to the track width direction (L) is defined as the length of the MR layer. An MR element set to about 1/5 or less, preferably about 1/10 or less of the length (h _MR ) from the surface to the edge described above,
An MR head having an R element is provided. The MR element of the present invention may be an MR element utilizing the anisotropic magnetoresistance effect (AMR) or an MR element utilizing the giant magnetoresistance effect (GMR) such as a spin valve. Good.

L (length of tapered portion) of MR layer to be formed /
h _MR (MR height) is about 1/5 or less, preferably about 1
The ion milling conditions are set so as to be / 10 or less. By defining the length of the tapered portion in this manner, M
A decrease in the R reproduction output can be prevented, and an increase in the resistance of the MR element can be prevented. Further, it is possible to prevent the accuracy of estimating the life of the MR element from being lowered.

[0007]

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

FIG. 1 is a sectional view schematically showing a layer structure of an MR head according to an embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes a lower shield layer;
Reference numeral 1 denotes an upper shield layer also serving as a lower magnetic pole layer on the recording head side, 12 denotes a shield gap layer inserted between the lower and upper shield layers 10 and 11, and 13 denotes an MR formed in the shield gap layer. Reference numeral 14 denotes a recording gap layer, 15 denotes an upper magnetic pole layer, 16 denotes a coil provided in an insulating layer 17, and 18 denotes an air bearing surface (ABS) facing the magnetic medium.

The MR layer 13 is made of, for example, NiFe or Ni
A ferromagnetic material such as FeCo (in the case of an AMR head) or a spin valve laminated structure (in the case of a GMR head) is formed in a strip shape extending in the track width direction. FIG. 2 is an enlarged view of only the MR layer 13. As is clear from the figure, the tapered portion 13a is formed at the edge of the MR layer 13 opposite to the ABS 18 due to the ion milling process when patterning the MR layer 13.

The tapered portion 13 in the direction of the MR height h _MR
It has been found that the length L of a can be controlled in accordance with ion milling conditions such as the ion beam incident angle and the thickness of a mask such as a resist for ion milling. For this reason, a plurality of MR heads are manufactured by changing the ion milling conditions, the MR element resistance is measured, and the MR height h _MR and the taper length L are measured using a scanning electron microscope (SEM).
Was measured.

FIG. 3 shows the measurement results, in which the horizontal axis represents h _MR / L, and the vertical axis represents the element resistance (ideal shape calculated value) calculated on the assumption that the tapered portion 13a does not have an ideal shape (L = 0). ), The increase rate of the measured element resistance (measured value), that is, (measured value−calculated value of ideal shape) / calculated value of ideal shape.

As apparent from FIG. 1, h _MR / L is about 5
Or more, preferably about 10 or more, that is, the length L of the tapered portion is M
If the R height h _MR is about 1/5 or less, preferably about 1/10 or less, the increase rate of the element resistance becomes 5% or less, which is a level that does not cause a problem as an actual MR head. Incidentally, by setting the ion beam incident angle to about 80 degrees or more, preferably 90 degrees (perpendicular to the plane of the MR layer), and setting the thickness of the mask to about 1.5 μm or less, preferably about 1.0 μm or less. , H _MR / L are about 10. As in the prior art, when the thickness of the mask is about 3.0 μm, h _MR / L is about 3, and in this case, the increase rate of the element resistance is as large as about 25%.

As in the present embodiment, h _MR / L is about 5 or more,
Preferably, the resistance is about 10 or more, so that an increase in resistance of the MR element can be prevented. Further, a decrease in the MR reproduction output can be prevented, and a decrease in the estimation accuracy of the life of the MR element can be prevented.

In the above-described embodiment, the ion milling process is used for patterning the MR layer 13, but other etching processes, for example, reactive ion etching (R
It is also possible to use IE) processing.

The embodiments described above are all illustrative of the present invention and not limiting, and the present invention can be embodied in other various modifications and alterations. Therefore, the scope of the present invention is defined only by the appended claims and their equivalents.

[0017]

As described above in detail, according to the present invention, the length L / MR height h of the tapered portion of the formed MR layer.
_{Since the MR} is set to be about 1/5 or less, preferably about 1/10 or less, a decrease in the MR reproduction output can be prevented, and an increase in the resistance of the MR element can be prevented. Further, it is possible to prevent the accuracy of estimating the life of the MR element from being lowered.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a layer configuration of an MR head according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion of an MR layer in FIG. 1;

FIG. 3 is a diagram showing a relationship between h _MR / L and a measured increase rate of element resistance with respect to a calculated ideal shape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lower shield layer 11 Upper shield layer 12 Shield gap layer 13 MR layer 13a Tapered part 14 Recording gap layer 15 Upper pole layer 16 Coil 17 Insulating layer 18 ABS

Claims (3)

[Claims] 1. A magnetoresistive element including a strip-shaped magnetoresistive layer extending in a track width direction, wherein an end portion of the magnetoresistive layer opposite to a surface facing a magnetic medium is provided. The length (L) of the tapered portion formed in the direction perpendicular to the track width direction to about 1/5 or less of the length (h _MR ) from the surface of the magnetoresistive layer to the edge. A magnetoresistive effect element characterized by being set. 2. A length (L) of a taper portion formed at an end portion of the magnetoresistive layer opposite to a surface facing a magnetic medium in a direction perpendicular to the track width direction. 2. The magnetoresistive element according to claim 1, wherein the length (h _MR ) from said surface of said magnetoresistive layer to said edge is set to about 1/10 or less. 3. A thin film magnetic head comprising the magnetoresistive element according to claim 1.