JPS63138516A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To shorten a working time in a manufacture process and to improve the yield of products by laminating a yoke previously smoothed by means of nonmagnetic and non electric conductive materials, a ferromagnetic magnetoresistance effect element and a return path in this order. CONSTITUTION:The soft magnetic thin film pattern of the same film thickness as the prescribed track width is formed on the same planar surface of a pair of yokes 2 in a thin film magnetic head. One ferromagnetic magnetoresistance effect MR element 4 and the return path 3 consisting of the soft magnetic thin film pattern magnetically connecting the elements 4 are provided on each end part of the yoke 2 without deteriorating the electrical continuity. A coil part by an upper coil 7 made of the electric conductive thin film is formed on the return path 3. The MR element 4 and the return path 3 are laminated in that order on the plane made of the nonmagnetic and non electric conductive materials through respective insulating films whereby the manufacturing process of the magnetic head is shortened and its yield is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thin film magnetic head manufactured using integrated thin film technology and used in magnetic disk devices, magnetic tape devices, etc.

(Prior Art) In recent years, in the field of magnetic recording, recording densities have been increasing rapidly, and there is a strong demand for thin film magnetic heads that support magnetic recording as well as recording media to be compatible with the above-mentioned higher recording densities.

An example of a thin film magnetic head adapted to such high recording densities, particularly narrow track widths, is a head having a structure as shown in FIG. 2, for example.

That is, Fig. 2(a) l:O'v'TeAl2O3
A pair of yokes 2 made of a soft magnetic thin film are formed on a substrate (not shown) made of monoceramics such as TiC using integrated thin film technology. Here, the yoke 2 is narrowed on its medium facing surface side, and a gap corresponding to a predetermined gap length (GL) is formed.

Furthermore, a return path 3 made of a soft magnetic thin film (for example, a CoZr film) is formed on the other end side of the yoke 2, and has the function of circulating magnetic flux from one yoke to the other yoke. A lower coil (not shown) and an upper coil 7 made of a conductive thin film of Cu, Au, etc. are formed in the return path 3, and constitute an electromagnetic induction type element section for writing information on a recording medium.

Furthermore, the space between the yoke 2 and the return path 3 is filled with a non-magnetic, non-conductive material such as silicon oxide, which is then flattened to form a magnetoresistive element (MR element) 4 made of NiFe alloy or NiCo alloy. , a magnetoresistive element section is disposed between the yoke 2 and the return path 3 and reads out information.

In this way, a thin film magnetic head is formed that combines both electromagnetic induction type and magnetoresistive type elements.

As mentioned above, the lower coil is not shown in order to avoid complication of the figure, but the lower coil is previously formed below the return path 3 and insulated from the return path 3, and the lower coil is insulated from the return path 3. After forming the yoke 2 and the return path 3, etc., the space between the yoke 2 and the return path 3 is filled and flattened with a non-magnetic, non-conductive material such as silicon oxide, and then electrically connected to the upper coil 7. The coils are combined and integrated without impairing continuity to form a coil wound on the return path 3.

Further, in FIG. 2, 6 is a terminal for connecting the MR element 4 or the coil section (lower coil and upper coil 7) to the circuit system, and 5 is an intermediate terminal for making the MR element 4 into a differential configuration. .

FIG. 2(b) is a schematic sectional view taken along the line AA in FIG. 2(a). Here, the gap between the yoke 2 and the return path 3 is filled and planarized with the silicon oxide film 8 as described above, and the MR element 4 is covered with an insulating layer (for example, a silicon oxide film) on each end thereof. membrane (not shown), the yoke 2
and the return path 3, the structure is such that they are stacked and arranged without impairing magnetic continuity.

In the thin film magnetic head shown in FIG. 2 as described above,
The track width Tw is defined by the film thickness of the yoke 2. Therefore, the narrowing of the track width is achieved by reducing the thickness of the soft magnetic thin film forming the cork 2, and there is no necessity to reduce the pattern width of the soft magnetic thin film pattern by etching to realize narrowing of the track width. Essentially, it has the advantage that narrowing the track width is simple and easy.Also, between the yoke 2 and the return path 3, which form the magnetic circuit, there is an M
Since the R element 4 is arranged and the MR element 4 has a differential configuration, there is an advantage that a large reproduction output can be obtained even if the track width is narrowed. Furthermore, since the MR element 4 comes into contact with the recording medium via the yoke 2, contact occurs.

There is also the advantage that noise generation in the MR element 4 due to sliding is suppressed.

(Problems to be Solved by the Invention) However, the thin film magnetic head shown in FIG. 2 has serious drawbacks as described below.

That is, as described above, the lower coil is formed from a conductive thin film such as Cu or Au prior to the process of forming the yoke 2 or the return path 3. After that, after forming an insulating layer such as silicon oxide on the lower coil, the yoke 2 and the return
Path 3 is formed. Furthermore, the space between the yoke 2 and the return path 3 is filled with a non-magnetic, insulating material such as silicon oxide, and is flattened, and an MR element 4 made of NiFe alloy or the like is placed between the yoke 2 and the return path.・Pass 3
It has a structure in which one of each is placed between.

By going through such a manufacturing process, the lower coil is completely covered with the insulating layer 1, for example, silicon oxide. At this time, the thickness of the insulating layer formed on the lower coil (1)
is at least the sum of the thickness (tl) of the interlayer insulating layer between the lower coil and return path 3 and the thickness (t2) of the insulating layer required to embed and flatten the yoke 2 and return path 3. It is. Here, tl is usually about 0.5 pm, while t2 is the yoke 2 or return path 3.
This is also equal to the predetermined track width, for example, in the case of a thin film magnetic head with a track width of 2 pm, t2
becomes 2pm. Therefore, the Jli thickness t of the insulating layer formed on the lower coil is as thick as at least 2.5 pm. Furthermore, since the film thickness t3 of the insulating layer between the upper coil 7 and the return path 3 is added to this, the film thickness of the insulating layer on the lower coil becomes larger.

The lower coil in the above state will be electrically connected to the upper coil 7 in the subsequent thin film magnetic head manufacturing process, and will become a series of coil parts that provide the thin film magnetic head with a write operation on a recording medium.

FIG. 3(a) shows a schematic cross-sectional view of the coil portion in such a state. Incidentally, this sectional view corresponds to the plane BB in FIG. 2(a). Here, unnecessary silicon oxide films deposited on the lower coil 9 (thicknesses of t1 and t
2. After removing the three-layer silicon oxide film t3 by ion etching or the like, an upper coil 7 is formed and connected to the lower coil 9, forming a series of coils surrounding the return path 3.

However, the connection process between the lower coil and upper coil 7 is
As mentioned above, etching is performed by removing the insulating layer to a thickness of at least 2.5 pm to expose a part of the lower coil, and then connecting the upper coil 7, which reduces workability and yield. This has caused an extremely serious problem in the manufacturing process of thin-film magnetic heads.

In other words, the etching process of the insulating layer is usually performed using a dry etching method, but the etching rate is at most 200 to 500 angstroms per minute (silicon oxide) under conditions that do not damage the photoresist pattern. ), and it took as much as 50 to 120 minutes to machine an insulating layer with a thickness of 2.5 pm.

In addition, at the same time as the yoke was flattened, the lower coil was also embedded in the insulating layer, and the lower coil had a pattern with a width of 5 to 10 pm.
Because they are minute, formed at intervals of 3 to 5 pm, alignment errors occur during exposure of the photoresist pattern for etching the insulating layer, which is necessary for connecting the upper coil 7, etc., resulting in a significant decrease in yield. .

Further, as shown in FIG. 3(b), a thick layer of photoresist 10 for forming the upper coil 7 is deposited in the recess formed by removing the insulating layer made of the silicon oxide film 8 on the lower coil 9. , the film thickness P1 of the photoresist 10 at the recessed portion is extremely large compared to the predetermined film thickness Pφ.

For this reason, when exposing the 7-oto-resist pattern of the upper coil 7, there was a problem in that part of the 7-oto-resist 10 remained in the above-mentioned recess.

This means that when the upper coil 7 is formed using the copper plating method, which is currently a common coil forming method for thin-film magnetic heads, the plating film will not be deposited at the connection part with the lower coil. Electrical continuity between the coil and the upper coil 7 is disrupted, resulting in a decrease in yield.

It is an object of the present invention to eliminate the various drawbacks of the conventional thin film magnetic head as described above, and to provide a thin film magnetic head with high recording density and high workability and yield in the manufacturing process. .

(Means for Solving the Problem) A pair of yokes made of a soft magnetic thin film pattern formed on the same plane and having a film thickness equal to a predetermined track width;
A ferromagnetic magnetoresistive element arranged at each end of the yoke without impairing magnetic continuity, and a soft magnetic thin film pattern that magnetically couples the ferromagnetic magnetoresistive elements to each other. A thin-film magnetic head is provided with a return path, and the return path is formed with a coil portion consisting of both upper and lower fills using a conductive thin film. A thin film magnetic head is obtained which has a structure in which the yoke, the ferromagnetic magnetoresistive element and the return path are laminated in this order, thereby solving the conventional problems.

(Function) By employing the above-described structure, the present invention has made it possible to provide a thin film magnetic head that has improved the conventional problems. That is,
A ferromagnetic magnetoresistive element and a return path are arranged in this order at the end of the yoke, which has been flattened with a non-magnetic, non-conductive material, without compromising magnetic continuity.
By adopting a laminated structure, the lower part of the insulating layer required to embed and flatten the yoke, which occupies most of the insulating layer formed on the lower coil formed at the bottom of the return path, is Since no deposition occurs on the coil, the thickness of the insulating layer on the lower coil is significantly reduced.

Therefore, the time required for the step of removing the insulating layer for connecting the lower coil and the upper coil is drastically reduced. According to the present invention, for example, in the case of a thin film magnetic head with a track width of 2 μm, which is the same as the conventional head described above, the thickness of the insulating layer on the lower coil is approximately 0.5 μm.
pm, and the time required for the insulating layer removal process is reduced to approximately 115, 10 to 25 minutes, compared to the conventional method.

At the same time, the depth of the recess formed by removing the insulating layer on the lower coil is also shallower, to about 115 mm compared to the conventional method, so the accumulation of the photoresist for forming the upper coil in the recess is suppressed, and the recess is reduced. This also solves the problem of photoresist remaining.

Furthermore, since the lower coil does not undergo the yoke flattening process due to its structure, it is not necessarily embedded in the insulating layer, and the occurrence of alignment errors in the insulating layer removal process is also suppressed, significantly improving the yield.

(Example) FIG. 1(a) is a schematic diagram showing an embodiment of the present invention.

In FIG. 1(a), a 2 pm CoZr (Zr: 10at, %) film is formed on a substrate (not shown) made of ceramics such as Al2O3-TiC by the spatch method, and a pair of Yoke 2 was formed. Here, the medium facing surface side of the yoke 2 was narrowed down and patterned to provide a gap corresponding to a predetermined gap length (GL). In this example, GL=0.4p
It is m. Note that the track width is equal to the film thickness of the yoke 2,
In this example, it is 2 pm.

Thereafter, a silicon oxide film with a thickness of about 2 pm was formed by sputtering, and the yoke 2 was buried and planarized using an etch-back method. In this planarization process, after forming a silicon oxide film, a novolak-based 7-OtoResist is spin-coated to a thickness of about 2.5 pm.
Heat treatment was performed with C for 1 hour to absorb the step difference in the yoke 2 and make it flat, and ion etching was performed in an Ar gas atmosphere. The conditions for ion etching are: Ar gas pressure 2×10' Torr, acceleration voltage: 500 Volt, and incident angle: θ=45°.

Next, a film of N1Fe (Fe: 18at, %) alloy is formed by vapor deposition, and a ferromagnetic magnetoresistive (MR) element 4 is formed on the end of the yoke 2 opposite to the gap side using photolithography. , and were unevenly laminated and arranged so as not to impair magnetic continuity. Note that the film thickness of the MR element 4 is 400 angstroms. Furthermore, prior to the deposition of the NiFe alloy, a silicon oxide film (not shown) is formed to electrically insulate the yoke 2 and the MR element 4.

A film having a thickness of 0.2 pm) was formed using a sputtering method.

After that, silicon oxide film again (not shown, film thickness 0.2 pm)
was formed by sputtering, and then a lower coil (not shown) made of Cu was formed by through-hole plating using a photoresist pattern.

The thickness of the Cu plating film was 2 pm.

Thereafter, a silicon oxide film (not shown, 0.5 pm thick) was sputtered to electrically insulate the lower coil and the return path 3.

After that, CoZr (Zr: 10at, %
) The film was sputtered and a return path 3 was formed using known photolithography. Here, return
The paths 3 are laminated and arranged so as to slightly overlap each end of the MRX element 4 so that magnetic continuity with the MR element 4 is not impaired.

Next, a 0.5 pm silicon oxide film (not shown) was formed by sputtering, and the unnecessary silicon oxide film on the lower coil was removed by ion etching. , an upper coil 7 made of Cu was formed so as to maintain electrical continuity with the lower coil.

Finally, a terminal 6 made of a conductive thin film connects the MR element 4 and the coil section (lower coil and upper coil 7) to the circuit system;
Intermediate terminals 5 were formed to produce a thin film magnetic head. still,
Specifically, the terminal 6 and the intermediate terminal 5 were formed of a Cu thin film pattern with a film thickness of 2 pm.

FIG. 1(b) is a schematic cross-sectional view taken along the line A-A in FIG. 1(a), in which the MR element 4 and The structure is such that the return paths 3 are stacked and arranged in this order with a silicon oxide film (not shown) interposed therebetween without impairing magnetic continuity.

In the thin film magnetic head according to the present invention, the manufacturing process, particularly the process of removing the unnecessary insulating layer (silicon oxide film in this example) on the lower coil, takes about 115 hours compared to the conventional thin film magnetic head. , and the yield was significantly improved.

Note that the performance of the thin film magnetic head of this example as a magnetic head, that is, the ability to write and read information to a magnetic recording medium, is completely comparable to that of a conventional thin film magnetic head, and the thin film magnetic head of this example has no inferiority to that of a conventional thin film magnetic head. It was confirmed that it has excellent performance as a magnetic head.

(Effects of the Invention) As described above, in the thin film magnetic head according to the present invention, it is possible to form the lower coil after burying the yoke 2 with the silicon oxide film 8 and flattening it. The thickness of the deposited insulating layer (silicon oxide film in this example) is drastically reduced.

Therefore, the working time for the process of removing unnecessary insulating layers on the lower coil is significantly shortened. Moreover, unlike yoke 2, the lower coil does not necessarily have to be embedded in an insulating layer.
The occurrence of alignment errors during photoresist pattern formation in this step is suppressed, and the yield is improved.

Furthermore, the depth of the recess created by removing the insulating layer is about 20% shallower than the conventional one, so the 7-photoresist for the upper coil 7 is prevented from accumulating in this recess, and the 7-photoresist pattern for the upper coil 7 can be exposed. At this time, the photoresist pattern does not remain in the above-mentioned recesses, and the yield is improved in this process as well.

As described above, in the thin film magnetic head according to the present invention, the working time of the manufacturing process is shortened and the yield is significantly improved, and it can be said that the present invention has great industrial value.

In the above description, only a silicon oxide film was mentioned as the insulating layer, but it goes without saying that other insulating materials such as an aluminum oxide film may be used.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are schematic diagrams showing an embodiment of a thin film magnetic head according to the present invention, and FIGS. 2(a) and (b) are schematic diagrams showing a conventional thin film magnetic head. . Figure 3 (a
) and (b) are schematic sectional views for explaining the problems of the conventional head. In the figure, 2...Yoke, 3...Return path, 4...
・MR element, 5... intermediate terminal, 6... terminal,
7... Upper coil, 8.0. Silicon oxide film, 9
...Lower coil, 10...Photoresist

Claims (2)

[Claims] (1) A pair of yokes made of a soft magnetic thin film pattern formed on the same plane with a film thickness equal to a predetermined track width, and a pair of yokes arranged at each end of the yokes without impairing magnetic continuity. Each of them includes one ferromagnetic magnetoresistive element and a return path made of a soft magnetic thin film pattern that magnetically couples the ferromagnetic magnetoresistive elements to each other, and furthermore, the return path is provided with a conductive thin film. In the thin-film magnetic head in which the coil portion used is formed, a ferromagnetic magnetoresistive element and a return path are arranged in this order on a plane consisting of a non-magnetic, non-conductive material and the yoke, respectively, via an insulating film. 1. A thin film magnetic head characterized by having a structure in which layers are laminated. (2) The thin film magnetic head according to claim 1, wherein each of the ferromagnetic magnetoresistive elements disposed at each end of the yoke has a differential configuration.