JPH06215331A - Composite thin film magnetic head - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a composite type thin film magnetic head having a structure capable of simultaneously producing two types of reproducing heads on the same substrate by a common process and obtaining a reproducing output sufficient for practical use. . [Structure] Upper yoke 9 and lower yoke 2 in which a gap is formed
To form a closed magnetic path of the signal magnetic field taken in from the gap 8, two gaps (12a, 12b) are formed in the upper yoke 9 along the direction of the signal magnetic field, and the upper yoke 9 is formed in the track width direction (signal magnetic field). (Direction and direction orthogonal)
Is divided into a predetermined number of tracks, and an analog MR element 6b that straddles some of the upper yokes 9 is arranged below the gap 12b in one row of the gaps, and below the gap 12a in the other row. One digital MR element 6a is arranged for each upper yoke 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite type thin film magnetic head used in a magnetic signal reproducing device such as a DCC.

[0002]

2. Description of the Related Art In recent years, with the increase in density of magnetic recording, many magnetoresistive heads (MR heads) are characterized by high reproduction output and constant output regardless of medium speed. It is used. FIG. 7 shows a general yoke type MR head (YMR head). FIG. 7A is a perspective view of the head, and FIG. 7B is a sectional view. A lower yoke 1 made of a magnetic material is formed on a substrate 101 made of a non-magnetic material.
02, an insulating film 103 made of SiO ₂ , Al ₂ O _3, etc., a bias line 104 made of a conductive material, an insulating film 105, an MR
An element 106, an insulating film 107 for forming a magnetic gap 108, and front and rear upper yokes 109a and 109b are formed. A high coercive force film 112 is formed on both ends of the MR element 106, and the lead conductor film 111 is connected to the MR element 106. Further, a passivation film 110 made of an insulating thin film such as SiO ₂ or Al ₂ O ₃ is formed on this. In a general YMR head, the MR element 106 is arranged in the gap between the front and rear upper yokes 109a and 109b in this way to supply a signal magnetic field to the MR element.

By the way, in recent years, a magnetic reproducing apparatus for audio (so-called DCC) capable of reproducing both an analog audio signal and a digital audio signal magnetically recorded has been actively developed. For this purpose, a composite thin film magnetic head having an independent reproducing function by combining an MR head for reproducing an analog signal and an MR head for reproducing a digital signal has been proposed. As an example thereof, there is a combination head (combi head) in which the analog reproducing head chip and the digital reproducing head chip are manufactured on different substrates, and the both are aligned and bonded. However, this composite type thin film magnetic head is difficult to be mass-produced because it requires extremely high accuracy in aligning the gaps between both heads and positioning in the manufacturing process.

As an example of solving this problem, there has been proposed a composite type head in which an analog signal reproducing head and a digital signal reproducing head are formed on the same substrate. A cross-sectional view of this example is shown in FIG. This composite type thin film magnetic head is constructed by stacking two MR heads having the structure shown in FIG. The same parts as those in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted. Since this composite type head is manufactured by stacking two types of reproducing heads on a substrate in order, the manufacturing process is more than twice as long as that of an ordinary thin film magnetic head, and the number and thickness of the thin films laminated on the substrate are increased. Increase significantly. This increases the probability of defective products due to increased substrate deformation, delamination, dust contamination, etc., and the yield of wafer process and assembly process is increased when two types of reproducing heads are separately manufactured on different substrates. Compared to, there was a drawback that it was significantly reduced.

Further, in order to solve this problem, there has been proposed a composite reproducing head in which an analog signal reproducing head and a digital signal reproducing head are arranged on the same substrate in front of and behind the tape sliding surface. A cross-sectional view of this example is shown in FIG. In FIG. 9, an analog signal reproducing head (MR element 1
(6) head) and a part of the yoke of the digital signal reproducing head (head of the MR element 106) are shared so that the conductor layer, MR element, yoke, interlayer insulating film and passivation film are the same film. Are formed at the same time.

[0006]

In the composite thin film magnetic head described above, most of the layers constituting the head are the same thin film,
Since it is possible to form at the same time by the same processing,
The number of manufacturing steps can be significantly reduced. However, since the analog MR element is structurally located at a portion approximately 100 μm away from the tape sliding surface, most of the signal magnetic field introduced from the medium leaks to the substrate side and the signal magnetic field introduced to the MR element is significantly reduced. To do. Therefore, conventional MR
There was a problem that the reproduction output was significantly reduced compared to the head. Especially, the reduction of the reproduction output in the high frequency region was not practically applicable.

In order to solve the above problems, the present invention has a structure capable of simultaneously producing two types of reproducing heads on the same substrate by a common process, and is capable of obtaining a reproducing output sufficient for practical use. The purpose is to provide a head.

[0008]

According to a first aspect of the present invention, there is provided an upper yoke and a lower yoke for forming a closed magnetic path of a signal magnetic field taken in from a gap, and an MR element is provided below a gap formed in the upper yoke. In a thin film magnetic head for detecting the signal magnetic field as a resistance change of the MR element, a plurality of rows of gaps of the upper yoke are provided along the direction of the signal magnetic field, and a plurality of the upper yokes are arranged in the track width direction. The MR element, which is divided into individual pieces and is provided below the gaps in the plurality of rows, is divided into one to a plurality of pieces in each row.

According to a second aspect of the present invention, the gaps in the plurality of columns are two columns, a gap for the analog MR element and a gap for the digital MR element. The MR element is arranged below the gap for the plurality of divided upper yokes, and the MR element is arranged below the gap for the digital MR element for each divided upper yoke. It is characterized in that one MR element is arranged.

[0010]

In the composite thin film magnetic head of the present invention, the upper yoke is provided with a plurality of rows of gaps, and the MR element is arranged below each of the plurality of rows of gaps. Since the signal magnetic field taken in from the head gap is shunted to the MR elements in each row when passing through the gaps in each row, the MR elements in each row can detect the signal magnetic field as a resistance change.
Further, the upper yoke is divided into a plurality of pieces in the track width direction, and the MR elements in each column are also divided into a plurality of pieces in accordance with this. This makes it possible to detect signals with different track widths. For example, as shown in claim 2, a column for arranging MR elements across some of the upper yokes to detect analog signals, and a column for arranging MR elements for each upper yoke to detect digital signals. Can be provided.

[0011]

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

[First Embodiment] FIG. 1 is a perspective view showing a structure of a first embodiment of the present invention, FIG. 2 is a sectional view of the same, and FIG. 3 is a plan view of the same. In the composite type thin film magnetic head of this embodiment, a lower yoke 2, an insulating film 3, a bias line 4, an insulating film 5, a digital signal MR element 6a, an analog signal MR element 6b, and a gap 8 are formed on a substrate 1. An insulating film 7, upper yokes 9a, 9b, 9c, and a passivation film 10 are formed for this purpose.

As shown in FIG. 3, the upper yoke 9 is divided into six in the track width direction. Further, two rows of gaps 12a and 12b are formed in the upper yoke 9,
Are divided into three (9a, 9b, 9c). MR elements 6a and 6b are formed below the gaps 12a and 12b, respectively. In this embodiment, the digital MR element 6a is arranged below the gap 12a, and the analog MR element 12b is arranged below the gap 12b. Six digital signal MR elements 6a are separately formed corresponding to the upper yoke 9 divided into six in the track width direction. A high coercive force film 13 is formed on both ends of each MR element 6a (see FIG. 1), and a signal lead wire 11a is connected thereto. That is, a 6-track digital head having a track width defined by the width L1 of the upper yoke divided into 6 is configured. On the other hand, the analog signal MR element 6b is formed over all the upper yokes 9 regardless of the divided state of the upper yokes 9. Therefore, a one-track analog head having a track width defined by the width L2 of the six upper yokes is formed.

Next, a method of manufacturing this composite type thin film magnetic head will be described.

A magnetic thin film of Ni-Fe, FeAlSi (sendust), amorphous metal or the like is plated on a non-magnetic substrate 1 such as alumina or other ceramic or glass by a method such as plating, sputtering, vapor deposition or CVD to a thickness of 1 to 20 μm. After the film is formed, the lower yoke 2 shown in FIG. 2 is processed by a means such as ion milling or wet etching into a shape extended to a position where the lower yoke 2 is joined to the end portion of the upper yoke 9b. Bias line 4 and the insulating layer to become an insulating film 3 Si0 _2, Al ₂ O ₃ or the like sputtered between the lower yoke 2, the deposition is deposited to a thickness of 0.3~5μm by a method such as CVD. Further, Al, Cu, A forming the bias line 4
Conductive thin film such as u, Ag or their alloys is deposited by sputtering, sputtering, CVD, plating, etc.
And is formed into a shape of the bias line 4 by a method such as wet etching or sputter etching using photolithography. After that, the insulating film 5 is made of the same material as that of the insulating film 3 by the same method as 0.3 to 5 μm.
To the thickness of. Further, an MR element 6 made of Ni-Fe or the like is formed thereon, and a high coercive force film 13 for single magnetization of the MR element 6 and a lead wire 11 are further formed on both ends of the MR element 6. . These MR elements 6,
The high coercive force film 13 and the lead wire 11 are formed by photolithography on the shapes of the digital MR element 6a, the analog MR element 6b, the high coercive force film 13 and the lead wires 11a and 11b, and are formed by wet etching, sputter etching, or the like. Process according to the method. After this, the insulating film 3,
After processing 5 into a shape in which a magnetic gap 8 is formed, an insulating film 7 is formed which serves as a magnetic gap between the front magnetic gap 8 and the MR elements 6a and 6b, and the upper yoke 9. Next, a magnetic film forming the upper yoke 9 is formed by the same method as that of the lower yoke 2 to a thickness of 0.1 to 5 μm, and then processed into the shapes of the upper yokes 9a, 9b and 9c. . Then, the passivation film 10 is replaced with the insulating films 3, 5
A magnetic head is completed by forming a film with the same material by the same method.

In the above composite reproducing head, the upper yoke 9a → the MR element for digital 6a → the upper yoke 9c → the MR element for analog 6b → the upper yoke 9b → the lower yoke 2
The closed magnetic circuit of is constructed.

[Second Embodiment] FIG. 4 shows the structure of a second embodiment of the present invention. FIG. 4 is a plan view of the head chip of the thin film magnetic head. The composite thin film magnetic head of the second embodiment differs from the composite thin film magnetic head of the first embodiment in that the arrangement of the digital MR element and the analog MR element is reversed. In the example, the analog MR element 16b is arranged on the front side close to the gap 8 and the digital MR element 1 is arranged on the side far from the gap 8.
6a is arranged. That is, on the side closer to the gap 8,
An analog head having a track width defined by the width L2 of the six upper yokes is configured, and a 6-track digital track having a track width defined by the width L1 of the upper yoke divided into six parts is formed on the side far from the gap 8. The head is constructed. In this composite type thin film magnetic head, a closed magnetic circuit is formed of the upper yoke 9a → the analog MR element 16b → the upper yoke 9c → the digital MR element 16a → the upper yoke 9b → the lower yoke 2.

[Third Embodiment] In the first embodiment, the bias line 4 is connected to each of the MR elements 6a, 6b, 16a, 16b.
However, the bias line may be commonly used in each MR element. For example, FIG. 5 is a diagram showing a cross-sectional structure of the head chip when the third embodiment is applied to the first embodiment.
It is commonly used in the lower layers of the R elements 6a and 6b.

[Fourth Embodiment] FIG. 6 shows the structure of a fourth embodiment of the present invention. FIG. 6A is a plan view of a head chip of the thin film magnetic head, and FIG. 6B is an external view of the thin film magnetic head. In the composite type thin film magnetic head of this embodiment, the upper yoke 29 divided into nine pieces is arranged on the left and right with respect to the center of the head chip. And one upper yoke 29
MR element 26a for digital whose track width is regulated by
Are provided for each of the upper yokes 29 to provide heads of 9 tracks on the left and right sides, and two analog MR elements 26b whose track widths are restricted by the four upper yokes 29 are provided on the left and right sides of each of the two tracks. The head. That is, since the track width can be designed so as to conform to the DCC standard, the present invention can be applied to a fixed head dedicated to DCC reproduction. As shown in FIG. 6, 18 upper yokes 29 are arranged on the tape sliding surface.

In this embodiment, the gap formed in the upper yoke is set in two rows and the analog MR element and the digital MR element are arranged. However, the gap formed in the upper yoke is two rows. The MR element provided below the gap may be either analog or digital.

[0021]

According to the composite thin film magnetic head of the present invention, several types of heads (generally for analog and digital) having different track widths can be formed on the same substrate. That is, several types of MR elements are arranged in the pair of upper and lower yokes. With this configuration, the main part of the YMR head can be formed at the same time, and the yoke, bias line, high coercive force film, etc. can be shared.
The number of steps and the number of thin film layers can be significantly reduced as compared with the conventional composite thin film magnetic head. Therefore, there is a great effect on the improvement of yield and reliability.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of a head substrate portion of a composite type thin film magnetic head according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of the same composite type thin film magnetic head.

FIG. 3 is a plan view of an essential part of the same composite type thin film magnetic head.

FIG. 4 is a plan view of an essential part of a composite type thin film magnetic head according to a second embodiment of the invention.

FIG. 5 is a cross-sectional view of an essential part of a composite type thin film magnetic head according to a third embodiment of the present invention.

FIG. 6A is a plan view of a main part of a composite type thin film magnetic head according to a fourth embodiment of the invention, and FIG. 6B is an external view of the thin film magnetic head.

FIG. 7A is a perspective view of a head substrate portion of a conventional composite thin film magnetic head, and FIG. 7B is a cross-sectional view of a main portion of the thin film magnetic head.

FIG. 8 is a sectional view of another conventional composite type thin film magnetic head.

FIG. 9 is a sectional view of another conventional composite thin film magnetic head.

[Explanation of symbols]

2 Lower yoke 6a, 16a, 26a Digital MR element 6b, 16b, 26b Analog MR element 8 Gap 9a, 9b, 9C, 29a, 29b, 29c Upper yoke 12a, 12b Gap

Claims (2)

[Claims] 1. A magnetoresistive element (hereinafter referred to as "M") provided with an upper yoke and a lower yoke that form a closed magnetic path of a signal magnetic field taken in from a gap, and below the gap formed in the upper yoke.
R element ". ) Is arranged to make the signal magnetic field MR
In a thin film magnetic head for detecting as a resistance change of an element, the gap of the upper yoke is provided in a plurality of rows along the direction of the signal magnetic field, the upper yoke is divided into a plurality in the track width direction, and the gap of the plurality of rows is provided. MR below
A composite thin-film magnetic head characterized in that the element is divided into one or more in each row. 2. A plurality of rows of gaps are two rows, a gap for an analog MR element and a gap for a digital MR element, and below the gap for the analog MR element. The MR element is arranged over some of the divided upper yokes, and one MR element is arranged for each divided upper yoke below the gap for the digital MR element. The composite type thin film magnetic head according to claim 1.