JP3047824B2 - Magnetoresistive thin-film conversion element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a magnetoresistive thin film transducer (hereinafter referred to as "MR type magnetic head element") used as a reproducing head element for a magnetic recording medium such as a hard disk.

[0002]

2. Description of the Related Art An MR type magnetic head element is a read-only magnetic head element for reproducing recorded information by detecting a magnetic field generated from a magnetic pole of a magnetic recording medium using an MR element. For example, a magnetic disk device such as a hard disk device is configured as an inductive / MR composite magnetic head in combination with an inductive magnetic head element for recording.

A conventional MR type magnetic head element generally has a magnetic sensor film (MR element) having a linear shape when viewed from a pole end face. In contrast, the applicant has first
Japanese Patent Application No. 6-340503 or Japanese Patent Application No. 6-3405
No. 04 proposed an MR type magnetic head element in which the shape of the magnetic sensor film viewed from the pole end face was trapezoidal. this is,
The main part has, for example, the structure shown in FIG. 2, and constitutes a lead 16 in which a magnet film 10, an electric conductive film 12, and a magnet film 14 are laminated on a lower gap (not shown).
A lead 18 is formed in the left and right portions 1
6a, 16b, and these left and right leads 16a, 1
6b, MR film 20, spacer 22, SAL
The magnetic sensor film 26 on which the bias film 24 is laminated is disposed over the entire surface of the groove 18 from the upper surfaces of the leads 16a and 16b.

According to such a trapezoidal magnetic sensor film 26, the left and right leads 16a, 16a of the magnetic sensor film 26 are provided.
b (a groove 18)
An active portion (sensitive portion = track width) 26a detects a signal recorded on a track of a magnetic recording medium (magnetic disk). On the other hand, the inclined portions 26b and 26c of the magnetic sensor film 26 formed on the inclined surfaces of the trapezoidal grooves 18 on both the left and right sides of the active portion 26a generate an azimuth angle with respect to the recording signal of the track, so that the reproduction sensitivity is lowered. . Therefore, even if the track is shifted left and right from the active portion 26a, the influence of the magnetic field from the track on the inclined portions 26b and 26c is reduced.
The influence of b and 26c on the magnetization of the active portion 26a is also reduced. Therefore, the left-right symmetry of the off-track characteristic is improved, and the side lobe is also reduced. As a result, tracking servo can be performed even on a narrow track, and high-density recording and reproduction can be realized. Also, crosstalk from adjacent tracks is reduced. Further, since the side lobe can be reduced without increasing the uniaxial anisotropic bias magnetic field, a decrease in the read sensitivity is also prevented.

[0005]

In the MR type magnetic head element 28 having the trapezoidal magnetic sensor film 26, since the magnetic sensor film 26 is bent at a portion 30 where the trapezoid transitions from the bottom surface to the slope, Due to the shape magnetic anisotropic effect, there is a problem that the MR film 20 is easily made multiaxial, and Barkhausen noise is easily generated. This phenomenon occurs particularly as the ratio of the depth (element height) of the magnetic sensor film 26 in the depth direction to the track width (aspect ratio = element height / track width) increases, and between the upper and lower shields sandwiching the magnetic sensor film 26. It became remarkable as the gap thickness became smaller.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce Barkhausen noise in an MR type magnetic head element having a trapezoidal magnetic sensor film.

[0007]

According to the present invention, the left and right end portions of the magnetic sensor film are cut at intermediate positions of the left and right inclined surfaces constituting the substantially trapezoidal groove of the lead. According to this, it is possible to increase the longitudinal bias magnetic field strength at the bent portion where the shape anisotropy effect of the magnetic sensor film occurs, so that Barkhausen noise can be suppressed.

[0008] Further, the lead has a structure in which a permanent bias magnet film for forming a single magnetic domain is arranged in a lower layer and an electric conductive film is arranged in an upper layer, so that the tip of the permanent bias magnet film for forming a single magnetic domain and the magnetic sensor are arranged. The distance from the bent portion of the film is shortened, whereby the longitudinal bias magnetic field strength at the bent portion of the magnetic sensor film is increased, so that Barkhausen noise can be further suppressed. In addition, this allows the single magnetic domain forming permanent bias magnet film to have a relatively small thickness and a relatively small saturation magnetizing force, so that the influence of the longitudinal bias magnetic field on the active portion (sensitive portion) of the magnetic sensor film can be reduced. It can be made small, and it is possible to prevent a large longitudinal bias magnetic field from being applied to the active portion to cause a decrease in sensitivity. In this way, it is possible to suppress Barkhausen noise by applying a strong longitudinal bias magnetic field to the bent portion of the magnetic sensor film while preventing the influence of the longitudinal bias magnetic field on the active portion of the magnetic sensor film.

[0009]

Embodiments of the present invention will be described below. FIG. 1 shows a configuration of a main part of an MR type magnetic head element to which the present invention is applied. MR type magnetic head element 34
Has a lead 36 formed on a lower gap (not shown). The lead 36 is made of a magnetic film 3 made of a hard bias (longitudinal bias) magnetic film such as CoCrPt.
8, a multilayer film formed by laminating an electric conductive film 40 having good electric conductivity such as W, Ta, Nb or the like. The magnet film 38 is magnetized in the longitudinal direction (track width direction). The lead 36 is formed by trapezoidal (inverted trapezoidal) grooves 42 so that the right and left portions 3
6a and 36b.

The magnetic sensor film 50 includes an MR film 44 made of NiFe or the like and a spacer 46 made of Ti or the like.
(MSL: Magnetic Spacer Layer) and a SAL bias film 48 made of a soft magnetic material. The easy axis of the MR film 44 is arranged in the track width direction. The magnetic sensor film 50 is disposed so as to connect the left and right leads 36a and 36b.
0a and 50b are cut at positions in the middle of the left and right inclined surfaces 42a and 42b of the groove 42. As a result, the magnetic sensor film 50 and the leads 36a, 36b are separated from the inclined surfaces 42a,
It is electrically connected at 42b. In the magnetic sensor film 50, the portion (the portion located on the bottom surface in the groove 18) 50c sandwiched between the sharp inner lower ends of the left and right leads 36a and 36b becomes the active portion, and is recorded on the track of the magnetic recording medium. The detected signal is detected. The left and right portions of the active part 50c of the magnetic sensor film 50 constitute inclined parts 50d and 50e.

The magnetic sensor film 50 has both ends 50a, 5a.
0b may be cut at any position on the inclined surfaces 42a and 42b, a conduction state between the lead 36 and the magnetic sensor film 50 can be obtained. Ideally, however, near the boundary between the electric conductive film 40 and the magnet film 38. (Actually, a margin is provided, and as shown in FIG. 1, cutting is performed at a position slightly in the electric conductive film 40 side from the boundary portion).

According to the above configuration, the current flows through the lead 36.
a (or 36b) to lead 3 on inclined surface 42a
6a flows to the magnetic sensor film 50 through the joint surface between the magnetic sensor film 50 and the lead 36 on the inclined surface 42b.
36b through the joint surface between the magnetic sensor film 50 and the magnetic sensor film 50
(Or 36a).

The magnet film 38 applies a bias magnetic field in the longitudinal direction of the magnetic sensor film 50 to reinforce the uniaxial anisotropy of the MR film 44 and prevent multi-axis. Since the magnet film 38 is disposed below the electric conductive film 40 and is located at substantially the same height as the magnetic sensor film 50, the front end portion of the magnet film 38 located at both ends of the track width (the inner lower end portion). The distance between the sharp portion) and the bent portions 52 and 54 where the MR film 44 of the magnetic sensor film 50 causes the shape anisotropic effect is minimized (0.1 μm or less).
Therefore, a magnetic field strong enough to cancel the demagnetizing field of the MR film 44 that causes the shape anisotropic effect can be applied to the bent portions 52 and 54, and the MR film 44 can be prevented from becoming multiaxial and Barkhausen noise can be reduced. Can be suppressed.

When the length of the magnetic sensor film 50 in the left-right direction is long and exists up to the upper surfaces of the leads 36a and 36b (in the case of the conventional structure of FIG. 2), the magnetic sensor film 50 and the magnet The magnetic field is weakened at the bent portions 52 and 54 of the magnetic sensor film 50 because the film 38 is magnetically coupled with a large area, whereas the left and right ends 50a and 50b of the magnetic sensor film 50 are Since it is cut in the middle of the inclined surfaces 42a, 42b, the bent portions 52,
At 54, the magnetic field strength by the magnet film 38 increases. For this reason, the bias magnetic field for canceling the demagnetizing field of the MR film 44 which causes the shape anisotropic effect can be increased at the bent portions 52 and 54, and the multi-axis of the MR film 44 can be further prevented, and Barkhausen noise is generated. Can be suppressed more effectively.

The magnetic sensor film 50 is connected to the lead portion 36.
If the magnetic sensor film 50 is present on the upper surfaces of the a and 36b, the track profile may be deteriorated due to the fluctuation of the anisotropic magnetic field. However, in the structure shown in FIG. This does not occur and the track profile can be kept good.

FIGS. 3 to 6 show the steps of manufacturing an inductive / MR composite magnetic head having the MR type magnetic head element 34 shown in FIG.
A description will be given with reference to the process chart of FIG. (1) An insulating film (alumina Al ₂ O) formed on a substrate (a wafer made of a ceramic material such as Al ₂ O ₃ —TiC, which is cut later to form a slider of a magnetic head) 52 ₃ etc.) Lower shield 56 on 54
And a lower gap 58 is formed. The lower shield 56 is
Permalloy (NiFe), Sendust (FeAlSi)
And the like are deposited by sputtering, vapor deposition or plating. The lower gap 58 is formed by depositing an insulating material such as alumina at 500 to 3000 angstroms.

(2) CoCr on the lower gap 58
A magnet film 38 such as Pt and an electric conductive film 40 such as W, Ta, and Nb are laminated by sputtering, vapor deposition, plating, or the like. As an example, CoCrPt is 50
A film of Ta is formed to a thickness of 1000 to 3000 angstroms as the electrically conductive film 60 at 0 to 2000 angstroms.

(3) Magnet film 38 and electric conductive film 40
Are etched all at once and cut into an inverted trapezoidal shape. The specific method is shown in FIG. First, (i) a resist 60 for cutting, for example, A
A novolak-based positive resist such as Z400K is formed by spin coating to a thickness of about 2 μm (three times or more the total thickness of the magnet film 38 and the electric conductive film 40). Next, (ii) the resist 60 is exposed and developed to a predetermined size to cut the groove 62 perpendicular to the wafer. (iii) When the wafer is placed on a hot plate and left at 200 ° C. for 30 minutes, the resist 60 reflows (melts), and the wall surface 60 a in the groove 62 is formed.
60b is tilted to about 40 °. (Iv) Irradiation with an ion beam 64 of argon or the like from a direction perpendicular to the wafer and plasma etching. As a result, the resist 60 is dug, and the inclined surfaces 60a and 60b recede in the horizontal direction. As the inclined surfaces 60a and 60b recede, the electric conductive film 40 is dug into an inverted trapezoid, and (v) the magnet film 38 is dug into an inverted trapezoid. Engraving is magnetic film 38
When the bottom surface of the lower gap 58 is reached (that is, when the upper surface of the lower gap 58 is exposed), the milling ends. In addition, the ion beam 6
By irradiating 4 with a slight inclination with respect to the vertical direction, the roughness of the milling surface can be prevented. (Vi)
Finally, when the resist 60 is removed, the leads 36a and 36b in which the inverted trapezoidal grooves 42 are cut are completed. The inclination angle θ of the inclined surfaces 42a, 42b of the completed leads 36a, 36b is expressed by the following equation.

Θ = tan ⁻¹ [(milling speed of lead materials 38, 40 / milling speed of resist 60) · tan α] In this equation, α is the initial inclined surfaces 60a, 60 of the resist 60.
When α = 40 ° at the inclination angle b (see FIG. 7 (iii)), the magnetic film 38 is made of CoCrPt, and the electric conductive film 40 is made of Ta.
Then, the inclination angle θ is about 20 °. The track width (the distance between the tips of the leads 36a and 36b) is controlled by the initial thickness of the lead members 38 and 40, the initial inclination angle α of the resist 60, and the initial width of the groove 62.

(4) When the trapezoidal groove 42 is formed,
An MR film 44 as a magnetic sensor film 50 on the entire surface of the wafer
(NiFe or the like), a spacer 46 (Ti or the like), and a SAL bias film 48 (a soft magnetic film such as CoZrM (Nb, Mo or the like)). (5) A resist is formed in the shape of the magnetic sensor film pattern to be formed on the magnetic sensor film 50, and unnecessary portions of the magnetic sensor film 50 are removed by milling.
0 is cut into a rectangular planar shape. As a result, the left and right end portions 50a and 50b of the magnetic sensor film 50 are inclined 42
a and 42b are cut in the middle.

(6) On the entire surface, insulation between the upper shield and the magnetic sensor film 50 and the upper shield and the leads 36a, 36
An upper insulating layer 68 is formed by forming an inorganic insulating film such as alumina for a shield gap with b. At this time,
If the left and right ends 50a and 50b of the magnetic sensor film 50 are located on the upper surfaces of the leads 36a and 36b (the conventional structure shown in FIG. 2), the steps at the left and right ends 50a and 50b are filled. It is necessary to form the upper gap 68 thick, but in this case, since the left and right end portions 50a and 50b are formed on the inclined surfaces 42a and 42b, the upper gap 68 can be formed as thin as necessary. , The effective gap length g can be shortened.

(7) Soft magnetic film (NiFe, FeAlS)
i) is deposited by plating, vapor deposition, sputtering or the like to form the upper shield 70. The upper shield 70 also serves as a lower core of the write head. (8) In order to eliminate irregularities on the surface of the upper shield / lower core 70, the upper shield / lower core 70 is mechanically polished with a lap or the like.
Flatten the surface.

(9) A write gap 72 (alumina or the like) for writing is formed on the upper shield / lower core 70. (10) The coil 74 and the insulating layer 76 are formed. (11) The upper core 78 is formed so as to straddle the coil 74 and the insulating layer 76 to form a write head (inductive magnetic head element). And finally, it is completed by covering with a protective film.

[0024]

As described above, according to the present invention, in an MR type magnetic head element having a trapezoidal magnetic sensor film, it is possible to prevent the magnetic sensor film from becoming multiaxial and to generate Barkhausen noise. It is possible to obtain a stable signal output.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional structure.

FIG. 3 is a perspective view showing an example of a manufacturing process of an inductive / MR composite magnetic head having the MR magnetic head element of FIG. 1;

FIG. 4 is a process drawing showing a continuation of FIG. 3;

FIG. 5 is a process drawing showing a continuation of FIG. 4;

FIG. 6 is a process drawing showing a continuation of FIG. 5;

FIG. 7 is a process chart showing details of step (3) in FIG. 3;

[Explanation of symbols]

34 MR type magnetic head element (magnetoresistive thin film conversion element) 36a, 36b Lead 38 Magnet film (permanent bias magnet film for forming a single magnetic domain) 40 Electrical conductive film 42 Trapezoidal groove 42a, 42b Inclined surface 50 Magnetic sensor film 50a, 50b Left and right end portions of magnetic sensor film 56 Lower shield 58 Lower gap 68 Upper gap 70 Upper shield

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 5/39

Claims (3)

(57) [Claims] 1. A lower shield, a lower gap constituting an insulating film formed on the lower shield, and a substantially trapezoidal groove formed on the lower gap and reaching the lower gap. A magnetic sensor film having an MR film formed along the groove so as to electrically connect the left and right leads; and an insulating film formed on the magnetic sensor film. An upper gap, and an upper shield formed on the upper gap, wherein the left and right ends of the magnetic sensor film are formed of left and right inclined surfaces forming a substantially trapezoidal cross section of the lead. A magnetoresistive thin-film conversion element that is cut at an intermediate position. 2. The magnetic device according to claim 1, wherein the lead is formed of a laminate in which an electric conductive film is laminated on a permanent magnetic bias film for forming a single magnetic domain with respect to the magnetic sensor film located at the bottom of the groove. Resistive thin-film conversion element. 3. A lower gap constituting an insulating film is formed on the lower shield, a lead material is formed on the lower gap, and the lead film is cut to obtain a substantially trapezoidal shape reaching the lower gap. A magnetic sensor film having an MR film is formed along the groove so as to electrically connect the left and right divided leads. The left and right end portions of the sensor film are cut at intermediate positions of the left and right inclined surfaces constituting the substantially trapezoidal groove of the lead, and the lead of the lead exposed on the magnetic sensor film and outside the magnetic sensor film is cut. A method for manufacturing a magnetoresistive thin-film conversion element comprising: forming an upper gap forming an insulating film thereon; and forming an upper shield on the upper gap.