JPH1011717A - Magnetoresistive effect head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetoresistive effect head in which an undesirable electric short circuiting in the periphery of the electric connection part between an electrode conductor and a shielding layer is precluded and the shielding layer serves also as one part of the electrode. SOLUTION: Since the electric short circuiting between an upper part shielding layer 28 and an electrode conductor 26a in the periphery of a first through hole 31 is prevented and it is never present to impair an electrode conductor 26b at the time of forming a second through hole 41 by forming the first through hole 31 and the second through hole 41 by a lift-off method or the like respectively in a stage laminating a first insulating layer 24 and in a stage laminating a second insulating layer 27, a magnetoresistive effect type head in which reliability at the time of operating of the head is good and yield at the time of manufacturing of the head is maintained can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus, and more particularly to a magnetic head utilizing a magnetoresistance effect used in a magnetic disk drive.

[0002]

[Prior art]

(01) In the field of magnetic recording, there is a demand for miniaturization of devices and improvement in areal recording density. For this reason, a conventional recording / reproducing inductive magnetic head cannot provide a sufficient reproducing output, and as a reproducing head, a magnetoresistive head capable of obtaining a high reproducing output irrespective of the relative speed between the head and the medium ( Hereinafter, it is abbreviated as MR head).

(02) An MR head is a transducer that converts a magnetic signal on a recording medium into an electric signal using a physical phenomenon in which the electric resistance of a magnetoresistive layer changes according to the direction of magnetization. In order to read recorded data from a recording medium having a high surface recording density, the magnetoresistive sensor portion of the MR head needs to be disposed between two magnetic shield layers. For example, U.S. Pat. No. 4,693,806 discloses an MR head including a shielded magnetoresistive sensor section.

(03) A signal detection electrode conductor is electrically connected to both ends of the magnetoresistive sensor portion, and the magnetoresistive sensor portion and the signal detection electrode conductor are located between a pair of insulating layers. Are arranged as follows. Further, the pair of insulating layers is disposed so as to be between the pair of shield layers.

(04) The gap between the shield layers, that is, the sum of the thickness of the pair of insulating layers and the thickness of the magnetoresistive sensor portion is called a gap. By reducing the gap, the resolution as an MR head increases. It is necessary to increase the resolution of the MR head according to the recording density of the recording medium. A magnetoresistive sensor unit used in a magnetic disk device or the like has a laminated structure, and it is difficult to easily reduce the thickness of the magnetoresistive sensor unit. Therefore, in order to increase the resolution, a method of reducing the gap by reducing the thickness of the pair of insulating layers is generally used. However, as the thickness of the insulating layer is reduced, the possibility that an electrical short circuit occurs between the signal detection electrode conductor and the shield due to pinholes or the like generated during the manufacturing process increases.

(05) Conventionally, in order to avoid an electrical short circuit caused by a pinhole generated in the insulating layer, the thickness of the insulating layer has been conventionally sufficiently increased. But as mentioned above
As the resolution required for the MR head increases, the thickness of the insulating layer must necessarily be reduced. Here, even when the thickness of the insulating layer is reduced, an MR head manufacturing technique for preventing an electrical short circuit between the electrode conductor and the shield is required.

(06) As one method for preventing an electrical short circuit between an electrode conductor and a shield even when the thickness of an insulating layer is reduced, a method described in Japanese Patent Application Laid-Open No. 07-065330 is used. According to this, it is possible to minimize the occurrence of an electric short circuit between the electrode conductor and the shield by using the conventional insulating layer. In JP-A-07-065330, one of the pair of electrode conductors is electrically short-circuited with one of the pair of shield layers, and the other of the pair of electrode conductors is connected to the other of the pair of shield layers. Electrical short-circuit between the two electrode conductors and the shield is made as close as possible to the connection between the magnetic recording sensor unit and the electrode conductor, and the two short-circuit intervals are formed. It states how to make it as short as possible. In this method, the shield layer functions as an electrode conductor for signal detection. When the shield layers are viewed as electrode conductors for signal detection, a pair of shield layers are separated by two insulating layers, so that the possibility of an electrical short between the shield layers is significantly reduced.

(07) Conventionally, as a manufacturing process of an MR head for electrically shorting an electrode conductor and a shield described in, for example, JP-A-07-065330, a lower shield layer is generally used. After forming the first insulating layer in order, as a through hole forming step for electrically short-circuiting one of the pair of electrode conductors to one of the pair of shield layers, 1) a desired photolithographic technique The steps of creating a pattern, 2) forming a through hole by chemical etching or physical etching, and 3) removing the pattern are performed. After this through-hole forming step, an electrode conductor layer is formed and, if necessary, patterning is performed. A similar through-hole forming step is performed in a manufacturing process of an MR head for electrically short-circuiting the other of the pair of electrode conductors with the other of the pair of shield layers.

(08) There is a problem of coverage in forming a through hole by chemical etching or physical etching. FIG. 1 is a diagram showing an MR head viewed from a direction perpendicular to the surface of a magnetic recording medium in order to explain a problem of coverage.
The figure enlarges an electrically short-circuited portion between the lower shield layer 11 and the electrode conductor 13, and a through hole 16 is formed on the first insulating layer 12 by chemical etching or physical etching so that the lower shield layer appears on the surface. After that, it is shown that the electrode conductor 13, the second insulating layer 14, and the upper shield layer 15 are sequentially formed. In the regions A and A ', the thickness of the second insulating layer 14 is smaller than that in the regions B and B', and this is called coverage. Due to the influence of the coverage, the withstand voltage between the upper shield layer and the electrode conductor is lower in the regions A and A 'than in the regions B and B'. Also, the protrusions C and C 'of the electrode conductor and the protrusions D and D' of the upper shield layer.
In such a case, discharge is likely to occur, leading to a decrease in the yield during the head manufacturing process and a decrease in the reliability of the head.

(09) Another problem is that in forming a through hole by etching, the thickness of the electrode conductor at the through hole becomes thin due to the difference in the etching rate between the insulating layer and the electrode conductor layer. In such a case, the electrode conductor in the through hole portion is lost by etching, and the electrical connection between the electrode conductor and the shield layer may be incomplete.

(10)

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to electrically short-circuit an electrode conductor and a magnetic shield layer, which can improve the yield during the head manufacturing process and ensure the reliability during the operation of the head. To provide an MR head having a structure using a magnetic shield layer as an electrode.

(11)

[0014]

According to the MR head of the present invention,
By manufacturing through-holes through the insulating layer to electrically short-circuit the electrode conductors and the magnetic shield layer by the lift-off method, it is possible to suppress the reduction in film thickness due to coverage and etching during the head manufacturing process and manufacture the head. The yield at the time can be improved, and the reliability at the time of head operation can be ensured. Further, by using the lift-off method, an etching step for forming a through hole in a head manufacturing step can be omitted, and the number of steps can be reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(01) FIG. 2 is a sectional view of a first embodiment of a read / write separated magnetic head according to the present invention, as viewed from a direction perpendicular to the recording medium surface. An MR head 20 is used as a reproducing head. The magnetoresistive head 20 includes, for example, a substrate 21, a base insulating layer 22, a lower shield layer 23, a first insulating layer 24, a magnetoresistive element 25, an electrode conductor 26a electrically connected to the lower shield layer 23, Electrode conductor 26b electrically connected to shield layer 28, second insulating layer 27, and upper shield layer 2
Consists of eight. The recording head uses a magnetic induction type head 29, and the upper shield layer 28 forms a part of the magnetic core of the magnetic induction type head 29.

(02) The substrate 21 is used as a slider body for supporting the element. A lower shield layer 23 is formed on a substrate 21 and separated by an insulating base layer 22. A first insulating layer 24 is laminated on the lower shield layer 23. At this time, a first through hole 31 for electrically connecting the lower shield layer 23 and the electrode conductor 26a is simultaneously formed. After the formation of the magnetoresistive element 25, a hard magnetic material functioning as a hard bias layer and a signal current are applied to both ends of the magnetoresistive element 25.
The electrode conductors 26a and 26b are formed as a laminate with a material having a small specific resistance to flow through. Next, a second insulating layer 27 is laminated to a required thickness, and an upper shield layer 28 is formed on the second insulating layer 27.
Is formed. When the second insulating layer 27 is laminated, a second through hole 41 for electrically connecting the upper shield layer 28 and the electrode conductor 26b is formed at the same time. In the above,
Although the first through hole 31 is on the side of the electrode conductor 26a and the second through hole 41 is on the side of the electrode conductor 26b, the second through hole 41 is formed on the side of the electrode conductor 26a.
The first through hole 31 may be formed on the side of 6b.

(03) As the substrate 21 serving as the slider body,
For example, an alumina titanium carbide sintered body commonly used in the art is used. For example, alumina is used as the material of the base insulating layer 22, and a thin film having a thickness of several tens of μm is formed by a sputtering method or the like. For example, Co
Using an NbZr amorphous alloy or the like, a thin film is formed to a thickness of about 2 μm by a sputtering method or the like. For the first insulating layer 24 and the second insulating layer 27, a thin film is formed by sputtering, for example, of a material having improved withstand voltage by adding SiO ₂ or the like to alumina to have a thickness of 50 to 150 nm. The upper shield layer 28 is formed as a thin film having a thickness of several μm using, for example, a NiFeN alloy as a material by a sputtering method or the like.

(04) The structure of the magnetoresistive element 25 is not restricted, and the following example is given as one of the structures of the magnetoresistive element 25. As the magnetoresistive layer, for example, a NiFe alloy having a thickness of several nm is used. A nonmagnetic metal separation layer is laminated on the magnetoresistive layer. For example, Ta having a thickness of several nm is used. As a soft magnetic metal layer for applying a lateral bias to the magnetoresistive layer on the separation layer, for example, NiFe having a thickness of several nm is used.
A material obtained by adding Cr, Rh, Nb, ZrO ₂ or the like to an alloy is used. Further, in order to prevent deterioration of the film in the head manufacturing process, a second protective layer having a thickness of several nm is formed on the soft magnetic metal layer.
May be formed. Each layer constituting the magnetoresistive element 25 is continuously laminated in a desired order by a sputtering method.

(05) The following example is given as one of the structures of the electrode conductors 26a and 26b. For example, a CoCrPt alloy having a thickness of several nm is used as a hard bias layer, and a crystalline metal layer, for example, Au, Cu, or the like having a thickness of several nm is laminated on the hard bias layer as a material having a low specific resistance. The layers constituting the electrode conductors 26a and 26b are successively laminated in a desired order by a sputtering method.

FIG. 3 is an enlarged view of the electrical connection portion 30 between the electrode conductor 26a and the lower shield layer 23 in the first through hole 31 of the magnetoresistive head 20 according to the present invention. First
At the edge of the through hole 31, the electrode conductor 26 of the first insulating layer 24
The surface contacting a and the surface contacting the lower shield layer 23 of the first insulating layer 24 intersect at an angle of 10 ° to 3 °, and the first through hole 3
One outline 32 is formed.

(04) The angle α between the first surface 33 of the first insulating layer and the second surface 34 of the first insulating layer, which shares a surface with the surface of the lower shield layer 23, is 10 ° ≦ α ≦ 30 by the lift-off technique.゜ becomes possible. As a result, a decrease in the thickness of the second insulating layer 29 at the step portion 35 of the first through hole can be minimized, and the problem of coverage is solved, leading to an improvement in yield.

(05) Further, the formation of the through-holes using the lift-off technique described above is also effective in that it does not affect the underlying layer in the area where the through-holes are formed. This is because, in the method of forming a through hole by patterning after forming an insulating layer and forming a through hole by etching, the thickness of the electrode conductor may be reduced due to a difference in etching rate between the insulating layer and the electrode conductor. Generally, the magnetic head is 5 inches φ
Although it is mass-produced on a substrate of about the same size, the thickness of the electrode conductor layer on this substrate is not uniform due to the characteristics of a film forming apparatus for forming the electrode conductor layer. For this reason, in a certain region on the substrate, even if the etching time is just right, the other region on the substrate may be too long or too short, and the yield of the thin film head is greatly reduced.

(06) The difference in the etching rate is particularly significant because the base in the second through hole 41 is an electrode conductor. FIG. 4 is an enlarged view of the vicinity of the second through hole 41, and shows an electrical connection portion 40 between the electrode conductor 26b and the upper shield layer 28. The effectiveness of the lift-off technique at the second through hole 41 is as follows. In the case where the second through hole 41 is formed by a conventional etching technique, the worst case is that the second through hole 41 is formed in the second through hole 41 due to the difference in etching rate due to the difference between the material of the second insulating layer 27 and the material of the electrode conductor 26b. The exposed electrode conductor 26b is etched. But,
The formation of the second through-hole 41 using the lift-off technique does not affect the electrode conductor 26b exposed in the second through-hole 41, and does not lower the yield of the thin film head.

(07) Referring to FIG. 5, the formation of a through-hole by the lift-off technique used in the present invention will be described. substrate
After forming the base insulating layer 22 on 21, the lower shield layer 23 is laminated. Lift-off pattern 51 for first through hole 31
Is formed by a photolithographic technique. First insulating layer
Stack 24. The lift-off pattern 51 for the first through hole 31 is removed. At this stage, the first insulating layer 24 and the first through hole 31 are formed. The magnetoresistive element 25 and the electrode conductor 26 are formed, and the electrode conductor 26a is electrically connected to the lower shield layer 23 through the first through hole 31.
Next, a lift-off pattern 52 for the second through hole 41 is formed by photolithography. Second insulating layer 27
Are stacked, and the lift-off pattern 52 for the second through hole 41 is removed. At this stage, the second insulating layer 27 and the second through hole 41 are formed. Finally, the upper shield layer 28
Are laminated, and the electrode conductor 26b is electrically connected to the upper shield layer 28 through the second through hole 41.

(08) In the present invention, the lower shield layer 23 and the upper shield layer 28 also serve as electrode terminals of the MR head. Terminals for electrically connecting to an electric circuit for signal detection are formed at optimum locations by a conventional technique by adjusting the shapes of the lower shield layer 23 and the upper shield layer 28.

(09) In the second embodiment according to the principle of the present invention, the electrode conductors electrically connected to the upper shield layer and the lower shield layer of the first embodiment are described below.
MR that minimizes the surface area of the electrode conductor facing the shield layer
Providing head. A second embodiment according to the principle of the present invention will be described with reference to FIG. FIG. 6 shows the shape of the electrode conductor 61 conventionally used for the MR head and the second shape according to the principle of the present invention.
A comparison with the shape of the electrode conductor 62 used in the example is shown. In a second embodiment according to the principles of the present invention, the electrode conductor 62 is
As shown in the figure, the long side 63 of the electrode conductor is in contact with the air bearing surface (ABS) of the head.

(10) From the principle of the present invention, it is sufficient that the electrode conductor 62 has a function for electrically connecting the magnetoresistive element 25 and the shield layer also serving as an electrode. On the other hand, a properly selected size is necessary for the hard bias layer laminated as a lower layer of the electrode conductor 62 to function, and a region for electrically connecting the electrode conductor 62 and the shield layer is required. Also need a properly selected size. Therefore, in the MR head according to the principle of the present invention, the above conditions are necessary and sufficient depending on the shape of the electrode conductor 62. The connection between the upper shield layer and the lower shield layer and the electrode conductor 28 is performed through a through hole 62 formed by a lift-off technique. According to the second embodiment in accordance with the principle of the present invention, there is provided a read / write separated magnetic head having, as a read head, an MR head having an excellent yield during a head manufacturing process and excellent withstand voltage performance during head operation.

(11) In the third embodiment according to the principle of the present invention, in the first embodiment or the second embodiment according to the principle of the present invention, an amorphous ferromagnetic layer is used as a shield layer. Provided is a magnetoresistive head having a laminated structure with a crystalline metal layer. The amorphous ferromagnetic layer provides the underlying surface roughness necessary for the magnetoresistive element 25 to operate effectively, and the crystalline metal layer is effective for radiating heat generated during the operation of the magnetoresistive element 25. is there. Further, when the shield layer is used as a part of the electrode, the low specific resistance of the crystalline metal layer also serves to suppress the heat generated by the signal current.

(11) As a material for the amorphous magnetic layer, for example, Co
NbZr amorphous is desirable, and as a material of the crystalline metal layer, for example, NiFe is desirable. As a laminated structure of the shield layer, a crystalline metal layer is laminated on the amorphous magnetic layer to form a basic structure, and the basic structure is laminated as a unit to a desired film thickness. For example, after forming CoNbZr amorphous 1.5 μm as an amorphous magnetic layer, NiFe as a crystalline metal layer
This one basic structure is used as a shield layer by laminating 0 .mu.m.

(12) In the third embodiment according to the principle of the present invention, the electrical connection between the shield layer and the electrode conductor is made between the crystalline metal layer which is a part of the shield layer and the electrode conductor. As described above, a laminated structure of the amorphous ferromagnetic layer and the crystalline metal layer constituting the shield layer is selected. Since the electrical connection with the electrode conductor is made between the crystalline metal layer and the crystalline metal layer, it is possible to suppress the generation of heat during the operation of the magnetoresistive head.

(13) The present invention provides an anisotropic magnetoresistance effect (AM
The present invention can be applied not only to an MR head using R) but also to a spin-valve MR head using a giant magnetoresistance effect (GMR).

[0032]

【The invention's effect】

1. By using the through-hole of the present invention, the MR head using the shield layer as an electrode by improving the yield during manufacturing and electrically shorting the electrode conductor and the shield layer, which have secured the reliability during operation, by using the shield layer as an electrode can get.

2. By using the through hole of the present invention and the electrode conductor having the shape of the present invention, one of the pair of shield layers electrically short-circuited with one of the pair of electrode conductors becomes the other of the pair of electrode conductors. And an MR head which does not cause an electrical short circuit is obtained.

3. The use of the shield layer having a laminated structure of the through hole and the amorphous magnetic film and the crystalline metal film according to the present invention improves the production yield,
MR that ensures reliability during operation and generates less heat during operation
The head is obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged view of the vicinity of a through hole formed by a conventional manufacturing method for explaining the features of the present invention.

FIG. 2 is a diagram of a recording / reproducing separation type head using an MR head as a reproducing head, as viewed from a direction perpendicular to a recording medium surface in a first embodiment.

FIG. 3 is an enlarged view around a first through hole formed by a method according to the present invention.

FIG. 4 is an enlarged view around a second through hole formed by a method according to the present invention.

FIG. 5 is an explanatory view of a manufacturing method for forming a through hole according to the present invention.

FIG. 6 is a comparison diagram of a shape of an electrode conductor used in a conventional MR head and a shape of an electrode conductor used in a second embodiment of a read / write separation type head using the MR head as a read head. .

[Explanation of symbols]

10… Electrical connection between electrode conductor and lower shield layer in conventional MR head, 11, 23… Lower shield layer, 12, 24
... first insulating layer, 13 ... electrode conductor, 14, 27 ... second insulating layer, 15, 28 ... upper shield layer, 16 ... conventional through hole, 20 ... MR head of the first embodiment, 21 ... substrate, 22: base insulating layer, 25: magnetoresistive element, 26a: electrode conductor connected to lower shield layer, 26b: electrode conductor connected to upper shield layer, 29: magnetic induction type head, 30: electrode conductor and lower Electrical connection portion with the shield layer, 31: first through hole, 32: contour of the first through hole, 33: first surface of the first insulating layer sharing a surface with the surface of the lower shield layer, 34 ...
The second surface of the first insulating layer, 35: a step portion of the first through hole, 40: an electrical connection portion between the electrode conductor and the upper shield layer, 41: a second through hole, 50: a through hole formed by a lift-off method Forming method, 51: Lift-off pattern for first through hole, 52: Lift-off pattern for second through hole, 60: Shape of conventional electrode conductor and shape of electrode conductor of the present invention, 61: Used for conventional MR head The electrode conductor that has been used, 62... The electrode conductor used in the second embodiment, 63... The long side of the electrode conductor used in the second embodiment.

Claims (4)

[Claims] 1. A lower magnetic shield layer of a ferromagnetic material, a first insulating layer of an electrically insulating material formed on the lower magnetic shield layer, and a magnetoresistive layer formed on the first insulating layer And a magnetoresistive sensor comprising a pair of electrode conductors formed at both ends of the magnetoresistive layer for passing a signal detection current through the magnetoresistive layer, and an electric sensor formed on the magnetoresistive sensor. A second insulating layer of insulating material;
In a read / write combined head using a magnetoresistive head formed in the order of a ferromagnetic material upper shield layer formed on an insulating layer as a read head, one of the pair of electrode conductors is provided on the first insulating layer. A second through hole electrically connected to the lower magnetic shield layer by the formed first through hole and the other of the pair of electrode conductors formed in the second insulating layer.
The first insulating layer is electrically connected to the upper magnetic shield layer by a through hole, wherein the magnetic shield layer is a part of an electric circuit through which the signal detection current flows. A first insulating layer facing the magnetic shield layer and a second surface of the first insulating layer facing the pair of electrode conductors, the first insulating layer being defined by a contour of a first through hole; The first surface of the layer intersects the second surface of the first insulating layer, and the inclination of the second surface of the first insulating layer at the contour of the first through hole is the first surface of the first insulating layer. And the second insulating layer has a first insulating surface facing the pair of electrode conductors and a second insulating layer facing the upper magnetic shield layer. And a second surface of the second insulating layer with a contour of a second through hole. One surface intersects the second surface of the second insulating layer, and the inclination of the second surface of the second insulating layer at the contour of the second through hole is relative to the first surface of the second insulating layer. 2. An angle of 10 to 30 [deg.].
The combined recording / reproducing head according to the above. 2. The pair of electrode conductors, wherein the pair of electrode conductors has a portion electrically connected to both ends of a magnetoresistive layer and a portion electrically connected to the magnetic shield layer. Each length is from the connection portion of the magnetoresistive layer to the connection portion of the magnetic shield layer, and the pair of electrode conductors has a structure also serving as a magnetic domain control layer, and the surface area of the pair of electrode conductors is 2. The recording / reproducing composite head according to claim 1, wherein the recording / reproducing composite head has a size enough to function as a control layer. 3. The shield layer has a laminated structure of an amorphous ferromagnetic layer and a crystalline metal layer, and the surface electrically connected to the electrode conductor is the crystalline metal layer. 3. The combined recording / reproducing head according to claim 1 or claim 2. 4. The method according to claim 1, wherein both the first and second through holes are formed by a lift-off method.