Thin film magnetic head and manufacturing method for creating high surface recording density and including a second yoke portion having two layers of which one is etched to form a narrow portion and a sloped flare portion

The invention is directed to improvement of a write element of a thin film magnetic head. In the write element, a first coil and a second coil are provided on a first insulating film formed on one surface of a first magnetic film and surround in a spiral form a back gap portion. A second yoke portion in the upper position comprises a wide portion, a narrow portion and a sloping flare portion. The wide portion has a flat surface and is connected to the first magnetic film by a back gap portion at the rear of the medium-facing surface. The narrow portion forms the second pole portion and the surface of the narrow portion being at a lower position than the surface of the wide portion. The sloping flare portion extends from the narrow portion to the wide portion, gradually increasing in width and its surface sloping upward away from the surface of the narrow portion to the surface of the wide portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin film magnetic head, a magnetic recording device using the same and a method for manufacturing the same, and particularly to improvement of a write element provided in a thin film magnetic head.

2. Discussion of Background

In recent years, the improvement in performance of a thin film magnetic head is demanded with the improvement in surface recording density of a hard disk device. The improvement in performance of a thin film magnetic head must be achieved in two aspects. One aspect is the improvement in performance of a read element, and the other is the improvement in performance of a write element.

The performance of a read element has been remarkably improved by development and practical use of a GMR (giant magnetoresistive) head provided with a spin valve film (SV film) or a ferromagnetic tunnel junction. Recently, this trend is so vigorous as to exceed a surface recording density of 100 Gb/p.

On the other hand, the improvement in performance of a write element has various problems to be solved as described below.

First, since a thin film magnetic head is used as a component of a magnetic recording device in a computer, it is demanded to be excellent in high-frequency characteristic and suitable for a high-speed data transfer. The high-frequency characteristic of a thin film magnetic head is determined by the structure of yokes and coils to form a write element. From such a view point, various prior arts have been proposed up to now.

For example, U.S. Pat. No. 6,043,959 discloses a technique in which a second yoke (upper yoke) is made flat to reduce the mutual inductance of coils and thus improve a high-frequency characteristic. U.S. Pat. No. 6,259,583B1 discloses a structure in which high-permeability and low-anisotropy layers, and non-magnetic layers are alternately stacked to form a second flat yoke.

A flat pole structure as disclosed in the above-mentioned prior arts is defined by photolithography, and a submicron process through a semiconductor process technique on the pole portion is necessary to achieve a narrow-track structure with an enhanced recording density. However, this submicron process is accompanied by the problems as described below.

First, the narrower the structure of a pole portion is made in a track structure, the more the pole portion is liable to cause a magnetic saturation, with degradation in a write ability. Thus a magnetic material with a high saturation magnetic flux density (hereinafter, referred to as an HiBs material) is needed to make the pole portion.

As HiBs materials, there are known FeN, CoFeN, NiFe, CoNiFe and the like. Among them, FeN, CoFeN and the like show a high saturation magnetic flux density of 2.4 T, for example, but they are difficult to form a pattern by plating, and consequently it becomes necessary to form a film of the material by sputtering and subsequently to pattern the film by ion milling. In case of a sputtering film as thick as 0.2 μm or more, accurate control over a track width of 0.2 μm or less, however, is very difficult, concerned with a mask made of photoresist or a mask formed of a magnetic film to form an upper pole.

On the other hand, NiFe, CoNiFe and the like can be easily patterned by plating. And NiFe provides a saturation magnetic flux density of 1.5 T to 1.6 T by increasing Fe in a composition ratio of Fe to Ni. Additionally NiFe is also easy to control the composition ratio.

For a surface recording density of 80 to 100 Gb/p, the track width gets as small as 0.1 to 0.2 μm, demanding a saturation magnetic flux density as high as 2.3 to 2.4 T, and NiFe cannot satisfy the demand. For a plating method, CoNiFe is suitable but CoNiFe is as low as 1.8 T or so in saturation magnetic flux density and cannot satisfy the high saturation magnetic flux density of 2.3 to 2.4 T required for a small track width of 0.1 to 0.2 μm.

Thus it has been usual that on a seed film to be a plating ground film is deposited a sputtering film of CoFe which is 2.4 T in saturation magnetic flux density, and thereon is subsequently deposited a plating film of CoNiFe which is 2.3 T in saturation magnetic flux density, for example.

In case of forming, for example, an upper pole by the above-mentioned technique, it is necessary to use the upper pole as a mask and thus trim the seed film below the upper pole by ion beam or the like in order to achieve a required narrow track width in the upper pole.

However, the seed film is, for example, a sputtering film of CoFe, and thus is very difficult to trimmed by ion beam. Due to this, in case of trimming a lower pole using an upper pole as a mask, the upper pole greatly reduces in film thickness. For example, the upper pole that has been formed as a plating film of 3 to 3.5 μm thick reduces as thin as 1.0 μm. The upper pole having such a thin film thickness causes a magnetic saturation in a write operation, with considerable degradation in an overwrite characteristic.

And since it is necessary to trim the upper pole to a very small width of 0.1 to 0.2 μm by means of ion milling, ion beams need to be applied at a large angle. Due to this, a part closer to the tip of the upper pole is more trimmed and therefore the upper pole is formed into the shape of a triangle or a trapezoid. Thus the upper pole reduces in volume and the reduction in volume increases a risk of a magnetic saturation.

Next, in case of trimming a pole, a trimming mask is deposited so as to surround an upper yoke portion and cover a coil portion, not to cover the upper yoke portion and the upper pole. The reason is that it has been thought that covering the whole of an upper yoke portion and an upper pole connected thereto causes a side wall at the edge of the mask pattern and the side wall deposited to the pole causes a side write phenomenon, side erase phenomenon or the like.

Further, as the upper yoke portion is not covered with a mask, a flare portion, which increases progressively in width from the upper pole to a wide portion of the upper yoke portion, is trimmed by ion beam, so that the flare point, at which the upper yoke portion begins to increase in width, backs away from the air bearing surface (hereinafter, referred to as ABS). This also reduces the magnetic volume, with degradation in the overwrite characteristic.

Generally, the closer the flare point of a flare portion is to the ABS, the more excellent overwrite characteristic is obtained. The flare point must be made close to the ABS, especially in the case of the small track width of 0.2 μm or less. In the conventional trimming method, the flare point recedes not only for the above-mentioned reason, but also for the following reason.

That is to say, as a trimming mask is deposited so as to surround an upper pole portion and cover a coil portion, not to cover the upper yoke portion and the upper pole, metal particles scattered by trimming the lower pole by ion beams are deposited on the side wall faces of the upper pole. To obtain a prescribed track width, the deposit film must be removed. To remove the deposit film, ion beams must be applied at a large angle of 50 to 75 degrees. This ion beam irradiation at a large angle narrows the upper pole. Furthermore, the pole is narrowed to have a taper angle making the width gradually smaller from the flare point toward the ABS, causing a problem that the track width varies according to individual thin film magnetic heads.

And while a narrow-track structure might be achieved by applying a semiconductor process technique on a flat pole structure to perform a submicron process on a pole portion, the surface of a flare portion expanding in width from the pole portion toward the yoke portion forms the same plane as the surfaces of the pole portion and yoke portion, causing problems that, in a write operation, the magnetic flux leaked from a side of the flare portion might erase a magnetic record on an adjacent track in a magnetic recording medium (side erase phenomenon), give a magnetic record to an adjacent track in a magnetic recording medium (side write phenomenon), or the like. Due to these problems, it is difficult to perform an accurate track control of 0.2 μm or less, and consequently it is impossible to achieve a high surface recording density of 100 Gb/p or more.

Next, it is known that in a thin film magnetic head of this type, the shorter the yoke length YL from the back gap to the pole portion is, the more excellent high-frequency characteristic is obtained. In order to shorten the yoke length, it is necessary to reduce the number of turns of a coil positioned between the back gap and the pole portion or to reduce the width of the coil without reducing the number of turns.

As the number of turns of a coil is determined by a magneto motive force required, however, reducing the number of coil turns to shorten the yoke length YL has a limit.

On the other hand, in case of reducing the width of a coil without reducing the number of coil turns, the electric resistance of the coil increases, so a temperature rise due to heat generation in a write operation increases. When the temperature rise increases, the pole portion thermally expands to cause a thermal protrusion that the pole portion swells on the ABS side. When a thermal protrusion occurs, the part where the thermal protrusion has occurred comes into contact with a magnetic recording medium in write and read operations, causing head crash, damage or destruction of a magnetic record on the magnetic recording medium. Consequently, a thermal protrusion must be strictly avoided. If it is impossible to avoid a thermal protrusion, the floating height of a thin film magnetic head must be increased after all, which makes it impossible to meet a demand for a low floating height for a high recording density.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a thin film magnetic head and a magnetic recording device suitable for a high surface recording density of 100 Gb/p or more.

Another object of the present invention is to provide a thin film magnetic head and a magnetic recording device of a high surface recording density type in which a sufficient over-write characteristic can be achieved in spite of a narrow track width.

A further object of the present invention is to provide a thin film magnetic head and a magnetic recording device of a high surface recording density type in which a pole comprises a material with a high saturation magnetic flux density of 2.2 to 2.4 T (referred to as an HiBs material) and has a track width of 0.1 to 0.2 μm.

A still further object of the present invention is to provide a thin film magnetic head and a magnetic recording device of a high surface recording density type having a high-frequency characteristic improved by shortening the yoke length.

A still further object of the present invention is to provide a thin film magnetic head and a magnetic recording device of a high surface recording density type having a yoke length of 5.5 μm or less.

A still further object of the present invention is to provide a thin film magnetic head and a magnetic recording device of a high surface recording density type in which the amount of generated heat is reduced by lowering the resistance of coils as keeping the number of coil turns.

A still further object of the present invention is to provide a manufacturing method suitable for manufacturing a thin film magnetic head described above.

In order to achieve the above-mentioned objects, in a thin film magnetic head according to the present invention, a second yoke portion (upper yoke portion) included in a write element comprises a wide portion and a narrow portion. The wide portion has a flat surface and is connected to a first yoke part by a back gap portion that is recessed in the thin film magnetic head from the medium-facing surface. Consequently, a write magnetic circuit going through the first yoke portion, the back gap portion, the second yoke portion and a write gap film is formed.

The coil surrounds in a spiral form the back gap portion on a first insulating film formed on a flat surface of the first yoke portion. Consequently, a magnetic flux is generated by a write current supplied to the coil, and flows through the write magnetic circuit going through the first yoke portion, the back gap portion, the second yoke portion and the write gap film, and leaks out in the vicinity of the gap film, and thus provides a magnetic recording medium with a magnetic record.

The narrow portion of the second yoke portion comprises a second pole portion and an flare portion. The second pole portion has a surface being at a position lower than the surface of the wide portion. The flare portion extends from the second pole portion to the wide portion, gradually increasing in width and its surface sloping upward away from the surface of the second pole portion to the surface of the wide portion.

In this structure, the sloping flare portion produces a three-dimensional difference in level between the surface of the second pole portion and the surface of the second yoke portion. The three-dimensional difference in level provides a large magnetic volume extending to the flare point, so the overwrite characteristic is improved. Accordingly, the present invention makes it possible to provide a thin film magnetic head of a high surface recording density type in which a sufficient overwrite characteristic is achieved in spite of a narrow track width.

Moreover, as the sloping flare portion is close to the ABS and its surface slopes upward away from the surface of the second pole portion to the surface of the wide portion of the second yoke portion, there is no risk that, in a write operation, a magnetic flux leaked from the sloping flare portion might erase a magnetic record provided on an adjacent track in a magnetic recording medium (side erase phenomena) or give a magnetic record to an adjacent track in a magnetic recording medium (side write phenomena).

Accordingly, the present invention makes it possible to provide a thin film magnetic head of a high surface recording density type which has a track width of 0.1 to 0.2 μm and is suitable for a high surface recording density of 100 Gb/p or more.

As a concrete aspect, the surface of the second pole portion and the surface of the sloping flare portion are obtained by etching part of the surface of a third magnetic film deposited on a second magnetic film. Preferably, the second magnetic film is made of a magnetic material containing Co and Fe. More concretely, the second magnetic film is made of CoFe or CoFeN. CoFe or CoFeN is an HiBs material of 2 to 2.4 T in saturation magnetic flux density, which produces a thin film magnetic head of a high surface recording density type having a track width of 0.1 to 0.2 μm.

Concretely, the second magnetic film of CoFe or CoFeN is formed as a sputtering film, which makes it possible to utilize the second magnetic film as a seed film for a plating process to form the third magnetic film on it. The third magnetic film is made of CoNiFe or the like.

As a preferable aspect, the first pole portion has a pole piece adjacent to the gap film, wherein the pole piece is trimmed at both sides in the width direction to have a narrow part having substantially the same width as the second pole portion and each indention formed by the trimming has a bottom increasing in thickness toward the narrow part. This structure makes it possible to avoid magnetic saturation in the pole piece adjacent to the gap film, and consequently improve the overwrite characteristic.

A magnetic film forming the pole piece adjacent to the gap film is made of CoFe, CoFeN, FeAlN, FeN, FeCo or FeZrN. The magnetic film can be formed as a plating film in case of CoFe or CoFeN, and can be formed as a sputtering film in case of FeAlN, FeN, FeCo or FeZrN.

The coil comprises a first coil and a second coil. The first and second coils surround in a spiral form the back gap portion on the surface of a first insulating film formed on one surface of the first yoke portion. One of the first and second coils is fitted into the space between coil turns of the other, insulated from the coil turns of the other by a second insulating film. The first and second coils are connected to each other so as to generate magnetic flux in the same direction.

The second insulating film between the first coil and the second coil can be formed as a very thin Al2O3film of about 0.1 μm in thickness by applying chemical vapor deposition (hereinafter, referred to as CVD) or the like. Therefore, it is possible to maximize the sectional area of the first and second coils between the back gap portion and the first pole portion, and consequently decrease the resistance of the coils and the quantity of generated heat as keeping the number of coil turns. This makes it possible to suppress occurrence of a thermal protrusion in a pole portion, and consequently avoid a head crash and the damage or destruction of a magnetic record on a magnetic recording medium and meet a demand for a low floating height for a high recording density.

As one of the first coil and the second coil is fitted into the space between coil turns of the other, insulated from the coil turns of the other by the second insulating film, high wiring density of coil conductors is achieved. This makes it possible to shorten the yoke length YL as keeping the same number of coil turns.

The first coil and the second coil are connected to each other so as to generate magnetic flux in the same direction. As the first coil and the second coil are the same in winding direction, it is possible to generate magnetic flux in the same direction by making a series-connection structure in which the inner end of the first coil is connected to the outer end of the second coil. Alternatively, magnetic flux may be generated in the same direction by connecting the first coil to the second coil in parallel. In this case, the number of coil turns decreases, but decrease in coil resistance is achieved.

The upper surfaces of the first coil and the second coil form the same plane. This structure makes it possible to form a common third insulating film on the upper surfaces of the first and second coils and so, an insulating structure on the upper surfaces of the first and second coils is simplified. And this structure provides a stable base for forming another coil above the first and second coils, so said another coil can be formed as a high-accuracy pattern.

In case of providing another coil on the first and second coils, the upper surfaces of the pole piece and the back gap piece are also made to form the same plane as the upper surfaces of the first and second coils in addition to flattening the upper surfaces of the coils. By doing so, a pole piece and a back gap piece required for providing another coil can be formed as a high-accuracy pattern on the flattened upper surfaces of the first pole piece and back gap piece.

In general, a thin film magnetic head according to the present invention forms a composite thin-magnetic head comprising a read element as well as a write element. The read element comprises a giant magnetoresistance effect element (hereinafter, referred to as a GMR element). The GMR element comprises a spin valve film or a ferromagnetic tunnel junction.

In case of manufacturing a thin film magnetic head as described above, a third magnetic film is formed so as to be uniform in film thickness and then the whole third magnetic film except parts to become a second pole portion and an inclined flare portion is covered with a resist mask.

Next, at least the parts which are to become the second pole portion and the inclined flare portion and are not covered with the resist mask are etched to obtain a track width made narrow.

According to the above-mentioned manufacturing method, it is possible to surely manufacture a thin film magnetic head according to the present invention.

An etching process as described above can include a process of etching said third magnetic film and said gap film under the existence of said resist mask and then exfoliating said resist mask, and thereafter etching said second magnetic film.

As a further other aspect, said etching process can include a process of performing the etching up to the surface of said gap film under the existence of said resist mask and then exfoliating said resist film, and thereafter etching said gap film and said second pole portion.

The present invention further also discloses a magnetic head device having a thin film magnetic head and a head supporting device combined with each other, and a magnetic recording/reproducing apparatus having this magnetic head device and a magnetic recording medium (hard disk) combined with each other.

Other objects, structures and advantages of the present invention are described in more detail with reference to the accompanying drawings. The drawings are only exemplifications.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

1. Thin Film Magnetic Head

Referring toFIGS. 1 to 4, a thin film magnetic head according to the present invention comprises a slider5, a write element2and a read element3. The slider5is, for example, a ceramic structure having a base body15made of Al2O3—TiC or the like with an insulating film16of Al2O3, SiO2or the like provided on the surface thereof (seeFIG. 3). The slider5has a geometrical shape for controlling a floating characteristic in the surface facing a medium. As a representative example of such a geometrical shape, there is shown an example being provided with a first step part51, a second step part52, a third step part53, a fourth step part54and a fifth step part55on a base face50at the ABS side. The base face50becomes a negative pressure generating portion to air flowing in the direction shown by arrow F1, the second step part52and the third step part53form a step-shaped air bearing rising from the first step part51. The surfaces of the second step part52and the third step part53form an ABS. The fourth step part54stands up in the shape of a step from the base face50and the fifth step part55stands up in the shape of a step from the fourth step part54. Electromagnetic converter elements2and3are provided in the fifth step part55.

The electromagnetic converter elements2and3comprise a write element2and a read element3. The write element2and the read element3are provided at the air flowing-out end (trailing edge) side when seeing in the air flowing direction F1.

Referring toFIGS. 3 and 4, the write element2comprises a first yoke portion211, second yoke portions221and222, a gap film24made of alumina or the like, a first pole portion P1, a second pole portion P2, a first coil231and a second coil232.

The first yoke portion211is formed of a first magnetic film. In the illustrated embodiment, as the first yoke portion211is formed of a first magnetic film of one layer, the first yoke portion211has the same meaning as the first magnetic film. For simplification, the following description may sometimes represent the first yoke portion211as the first magnetic film211.

The first magnetic film211is supported by an insulating film34and its surface is made substantially flat. The insulating film34is made of an inorganic insulating material such as Al2O3, SiO2, AlN or DLC.

The second yoke portions221and222face the first yoke portion211with an inner gap between the second yoke portions and the inner gap. The second yoke portions221and222have a structure in which a second magnetic film221and a third magnetic film222are stacked. For simplification of the description, the second yoke portions221and222may be sometimes represented as the second magnetic film221and the third magnetic film222.

The first magnetic film211, the second magnetic film221and the third magnetic film222can be made of one or more magnetic materials selected from NiFe, CoFe, CoFeN, CoNiFe, FeN, FeZrN and the like. Each of the first magnetic film211, the second magnetic film221and the third magnetic film222is determined within a range of 0.25 to 3 μm in thickness, for example. Such first magnetic film211, second magnetic film221and third magnetic film222can be formed by a sputtering method, a frame plating method or their combination.

In the illustrated embodiment, it is assumed that the first magnetic film211is made of CoFeN or CoNiFe. The third magnetic film222can be made of CoNiFe, and the second magnetic film221can be made of CoFeN being high in saturation magnetic flux density.

The front end portions of the first magnetic film211, the third magnetic film222and the second magnetic film221form parts of the first pole portion P1and the second pole portion P2opposite each other with a very thin gap film24, and a write operation is performed in the first pole portion P1and the second pole portion P2. The gap film24is made of a non-magnetic metal film or an inorganic insulating film such as alumina.

In the illustrated embodiment, the first pole portion P1has a structure in which a second pole piece212, a third pole piece213and a fourth pole piece214are deposited in this order on a first pole piece formed of an end portion of the first magnetic film211. The second pole piece212, the third pole piece213and the fourth pole piece214are made of an HiBs material such as CoFeN or CoNiFe.

The second pole portion P2has a structure in which a fifth pole piece221formed of an end portion of the second magnetic film221and a sixth pole piece224formed of an end portion of the third magnetic film222are deposited in this order on the gap film24.

Referring toFIG. 4, the end portion of the first magnetic film211, the second pole piece212and the third pole piece213spread in the track width direction of the ABS. However, the fourth pole piece214has the upper end portion narrowed at both sides in the track width direction to produce a narrow track width PW, and the gap film24deposited thereon, the fifth pole piece221formed of the end portion of the second magnetic film221and a sixth pole piece224formed of the end portion of the third magnetic film222have also nearly the same narrow track width PW as the fourth pole piece214. Consequently, the narrow track width PW for high-density recording is obtained.

The third magnetic film222and the second magnetic film221extend to the rear side of the ABS52,53as keeping an inner gap between the first magnetic film211and them, and are connected to the first magnetic film211by back gap pieces216,217and218. Consequently, a thin film magnetic circuit going through the first magnetic film211, the third magnetic film222, the second magnetic film221and the gap film24is completed.

The inner gap is filled up with insulating films254to256and the gap film24, and the second yoke portion comprised of the second magnetic film221and the third magnetic film222is formed on the gap film24.

The second yoke portion comprised of the second magnetic film221and the third magnetic film222comprises a wide portion223, a narrow portion224and a flare portion225. The wide portion223has a flat surface and is connected to the first magnetic film211by the back gap pieces216to218that are recessed in the thin film magnetic head from the ABS52,53. Consequently, a write magnetic circuit going through the first magnetic film211, the back gap pieces216to218, the second magnetic film221, the third magnetic film222and a write gap film24is formed.

The narrow portion224is a part forming the second pole portion P2and its surface is at a position lower than the surface of the wide portion223. The flare portion225extends from the second pole portion P2to the wide portion223, gradually increasing in width and its surface sloping upward away from the surface of the second pole portion P2to the surface of the wide portion223.

Consequently, the sloping flare portion225produces a three-dimensional difference in level ΔH1between the surface of the narrow portion forming the second pole portion P2and the surface of the wide portion223(seeFIG. 3). The three-dimensional difference in level ΔH1provides a large magnetic volume extending to the flare point FP1(seeFIG. 3), so the overwrite characteristic is improved. Accordingly, the present invention makes it possible to provide a thin film magnetic head of a high surface recording density type in which a sufficient overwrite characteristic is achieved in spite of the narrow track width PW.

Moreover, as the sloping flare portion225is close to the ABS52,53and its surface slopes upward away from the surface of the narrow portion224to the surface of the wide portion223, there is no risk that, in a write operation, magnetic flux leaked from the sloping flare portion225might erase a magnetic record provided on an adjacent track in a magnetic recording medium (side erase phenomena) or give a magnetic record to an adjacent track in a magnetic recording medium (side write phenomena).

Accordingly, the present invention makes it possible to provide a thin film magnetic head of a high surface recording density type which has a track width of 0.1 to 0.2 μm and is suitable for a high surface recording density of 100 Gb/p or more.

In the first pole portion P1, the fourth pole piece214adjacent to the gap film24has a film thickness larger than the three-dimensional difference in level ΔH1made by the sloping flare portion225and has a base portion extending in the width direction in both sides. This structure allows the fourth pole piece214to have an increased sectional area in addition to an HiBs characteristic, and the increased sectional area prevents magnetic saturation in the fourth pole piece214. Consequently, an improved overwrite characteristic is obtained.

As a concrete aspect, the surface of the narrow portion224and the surface of the sloping flare portion225are obtained by etching part of the surface of the third magnetic film222deposited on the second magnetic film221. Preferably, the second magnetic film221is made of a magnetic material containing Co and Fe. More concretely, the second magnetic film221is made of CoFe or CoFeN. CoFe or CoFeN is an HiBs material of 2.2 to 2.4 T in saturation magnetic flux density, which produces a thin film magnetic head of a high surface recording density type having a track width of 0.1 to 0.2 μm.

Concretely, the second magnetic film221of CoFe or CoFeN is formed of a sputtering film, which makes it possible to utilize the second magnetic film221as a seed film for a plating process to form the third magnetic film222on it. The third magnetic film222is made of CoNiFe or the like.

Next, referring toFIG. 6together withFIGS. 3 to 5, the first and second coils231and232surround the back gap pieces216to218. The first coil231is in a spiral shape and is formed on the surface of an insulating film251formed on a flat surface of the first magnetic film211, and the pattern of the first coil231is wound in a flat form around an axis perpendicular to the surface of the insulating film251. The first coil231is made of a conductive metal material such as Cu (copper). The insulating film251is made of an inorganic insulating material such as Al2O3, SiO2, AlN or DLC.

The second coil232is also in a spiral shape and is fitted into the space between coil turns of the first coil231, insulated from the coil turns by an insulating film252, and the pattern of the second coil232is wound in a flat form around the axis. The second coil232is also made of a conductive metal material such as Cu (copper). The insulating film252is made of an inorganic insulating material such as Al2O3, SiO2, AlN or DLC.

The periphery of the first coil231and the second coil232is filled up with an insulating film253(seeFIG. 3). The insulating film253is also made of an inorganic insulating material such as Al2O3, SiO2, AlN or DLC.

The insulating film252between the first coil231and the second coil232can be formed as a very thin Al2O3film of about 0.1 μm in thickness by applying a CVD process or the like. Therefore, it is possible to maximize the first coil231and the second coil232in sectional area, and consequently decrease the coil resistance and the quantity of generated heat as keeping the number of coil turns. This makes it possible to suppress occurrence of a thermal protrusion in the pole portions P1, P2during a write operation, and consequently avoid a head crash, damage and destruction of a magnetic record on a magnetic recording medium and meet a demand for a low floating height for a high recording density.

As the second coil232is fitted into the space between coil turns of the first coil231, insulated from the coil turns by the insulating film252, high wiring density of coil conductors is achieved. This makes it possible to shorten the yoke length YL (seeFIG. 3) as keeping the same number of coil turns and so, the high-frequency characteristic is improved.

The first coil231and the second coil232are connected to each other so as to generate magnetic flux in the same direction. As the first coil231and the second coil232have the same winding direction, it is possible to generate the magnetic flux in the same direction by making a series-connection structure in which the inner end281of the first coil231and the outer end283of the second coil232are connected to each other by a connecting conductor282. The outer end286of the first coil231is connected to a terminal284by a connecting conductor285, led outside by a lead conductor291and connected to a takeout electrode. The inner end287of the second coil232is connected to a terminal289by a connecting conductor288, led outside by a lead conductor292and connected to a takeout electrode.

Unlike the structure shown inFIG. 6, magnetic flux may be generated in the same direction by connecting the first coil231and the second coil232in parallel with each other. In the case, the number of coil turns decreases, but decrease in the coil resistance is achieved.

Moreover, the second coil232is separated from the second pole piece212and the back gap piece216by the insulating film252which can be formed as a very thin film of about 0.1 μm in thickness by applying CVD or the like. This makes it possible to promote shortening of the yoke length YL.

The upper surfaces of the first coil231and the second coil232form the same plane. This structure makes it possible to form a common insulating film254on the upper surfaces of the first coil231and the second coil232and so, an insulating structure on the upper surfaces of the first coil231and the second coil232is simplified. And this structure makes it possible to form a flat and stable base face on the first coil231and the second coil232and thereafter form a high-accuracy pattern.

In this case, the first coil231is a plating film and is formed on an insulating film251deposited on one surface of the first magnetic film211. The second coil232is also a plating film and is formed on an insulating film252in the space between coil turns of the first coil231. The insulating film252is formed on the bottom face and both side faces of the space.

A protective film258covers the whole write element2. The protective film258is made of an inorganic material such as Al2O3or SiO2.

In the vicinity of the read element3, there are provided a first shield film31, an insulating film32and a second shield film33. The first shield film31and the second shield film33are made of NiFe or the like. The first shield film31is formed on an insulating film16made of Al2O3, SiO2or the like. The insulating film16is formed on the surface of a base body15made of Al2O3—TiC or the like.

The read element3is provided inside the insulating film32between the first shield film31and the second shield film33. The end face of the read element3comes out at the ABS52,53. The read element3comprises a giant magneto-resistance effect element (GMR element). The GMR element can be formed of a spin valve film or a ferromagnetic tunnel junction element.

Next, another embodiment of a thin film magnetic head according to the present invention is described with reference toFIGS. 7 and 8. InFIGS. 7 and 8, the same components as those shown inFIGS. 1 to 6are given the same reference symbols. A thin film magnetic head of the illustrated embodiment has the same basic structure as the thin film magnetic head shown inFIGS. 1 to 6.

One of differences between a thin film magnetic head shown inFIGS. 7and8and the thin film magnetic head illustrated and described inFIGS. 1 to 6is that in the thin film magnetic film shown inFIGS. 7 and 8, conductive layers282to285are deposited on the inner end281of the first coil231and a connecting conductor for connecting the first coil231to the second coil232is formed. The conductive layers282to285are respectively formed and patterned by the same processes as those of a third pole piece213, a fourth pole piece214, a second magnetic film221and a third magnetic film222.

Consequently, the thin film magnetic head shown inFIGS. 7 and 8has an advantage that a process of forming a connecting conductor for connecting the first coil231to the second coil232is simplified in addition to the advantages of the thin film magnetic head shown inFIGS. 1 to 6.

Still another embodiment of a thin film magnetic head according to the present invention is described with reference toFIG. 9. InFIG. 9, the same components as those shown inFIGS. 1 to 6are given the same reference symbols. A thin film magnetic head of the illustrated embodiment has the same basic structure as the thin film magnetic head shown inFIGS. 1 to 6.

One of differences between a thin film magnetic film shown inFIG. 9and the thin film magnetic head illustrated and described inFIGS. 1 to 6is that in the thin film magnetic head shown inFIG. 9, conductive layers282to284are deposited on the inner end281of the first coil231and a connecting conductor for connecting the first coil231to the second coil232is formed. The conductive layers282to284are respectively formed and patterned by the same processes as those of the third pole piece213, the second magnetic film221and the third magnetic film222.

The thin film magnetic head shown inFIG. 9has an advantage that a process of forming a connecting conductor for connecting the first coil231to the second coil232is simplified in addition to the advantages of the thin film magnetic head shown inFIGS. 1 to 6.

Another difference is that the head ofFIG. 9has only the first coil231, the space between coil turns of the first coil231being filled with the insulating film252, the insulating film252being covered with an insulating film254.

2. Method for Manufacturing a Thin Film Magnetic Head

Embodiment 1 related to a manufacturing method is a process of manufacturing a thin film magnetic head of a first aspect having a first coil231and a second coil232(FIGS. 1 to 6). It is notified in advance that processes illustrated inFIGS. 11 to 44are performed on a wafer.

First, referring toFIG. 10, on an insulating film16deposited on a base body15there are formed a first shield film31, a read element3, an insulating film32, a second shield film33, an insulating film34and a first magnetic film211by means of publicly known processes. After that, an insulating film251is formed on the flat surface of the first magnetic film211, the insulating film251having an area slightly larger than an area necessary for forming a coil, and then a seed film260is formed on the surface of the insulating film251. The seed film260is formed so as to cover the surface of the insulating film251and the surface of the first magnetic film211. The seed film260is made of a material suitable for a Cu-plating ground and is formed 50 nm to 80 nm thick by a Cu-CVD process.

Next, a photoresist film RS1is formed on the seed film260by applying a spin coating method or the like and then is exposed through a mask MSK having a coil pattern and developed. Consequently, a resist frame FR1having a specified pattern is formed as shown inFIG. 11. The photoresist film RS1may be either positive photoresist or negative photoresist. In the embodiment, the case of using positive photoresist is described as an example.

Next, a selective Cu-plating process is performed so that a first coil231is grown to be 3 to 3.5 μm thick on the seed film260inside the coil forming pattern S1.FIG. 12shows a state in which the above-mentioned selective Cu-plating process has been performed.

Next, as shown inFIG. 13, the resist frame FR1is removed by means of chemical etching or the like. After that, a photolithography process for forming a pole piece and a back gap piece is performed so that a resist frame for forming the pole piece and the back gap piece is formed.

Next, a selective plating process is performed so that the pole piece and the back gap piece are grown on the first magnetic film211. After that, the resist frame is removed by means of chemical etching or the like. Consequently, as shown inFIG. 14, the pole piece212and the back gap piece216are formed with a space between them on one surface of the first magnetic film211.

Next, as shown inFIG. 15, a photoresist film RS2covering the first coil231, the pole piece212and the back gap piece216is formed. After that, a photolithography process is performed on the photoresist film RS2so that a resist cover FR2covering the first coil231and its periphery is formed as shownFIG. 16. In addition, an insulating film253covering the whole resist cover FR2is deposited thereon. The insulating film253is formed 4 to 5 μm thick.

Next, the insulating film253and the resist cover FR2are polished by chemical mechanical polishing (hereinafter, referred to as CMP) to be flattened. Alumina-based slurry is used in the CMP.FIG. 17shows a state in which the CMP process has been performed.

Next, the resist cover FR2is removed and after that, an insulating film252is deposited on the surfaces and side faces of the insulating films251and253, the first coil231, the second pole piece212and the back gap piece216. Concretely, the insulating film252is formed about 0.1 μm in thickness by an Al2O3-CVD process.

Furthermore, a seed film261is deposited 0.05 to 0.1 μm thick on the surface of the insulating film252by a Cu-CVD process.

Next, as shown inFIG. 18, a plating film232to be a second coil is formed, for example, 5 μm thick on the seed film261. The plating film232comprises Cu as its main constituent.

Next, as shown inFIG. 19, the plating film232is polished to be flattened by CMP. Alumina-based slurry is used in the CMP. Consequently, the second coil232of a flat spiral pattern is obtained, insulated from the first coil231by the insulating film252. In CMP, the surfaces of the pole piece212, the back gap piece216and the insulating film253are also polished so as to form the same plane as the surfaces of the first coil231and the second coil232.

Next, an insulating film254covering the surfaces of the first coil231and the second coil232is deposited thereon. The insulating film254is made of Al2O3to be 0.2 μm thick, for example.

Next, a photolithography process is performed on one surface where the insulating film254has been formed, so that a resist frame for forming a connecting conductor282for connecting the inner end281of the first coil231with the outer end283of the second coil232(seeFIG. 6) and a resist frame for forming a third pole piece213and a back gap piece217(seeFIG. 7) are formed. According to the patterns defined by the resist frames thus obtained, a frame plating method is performed. Consequently, as shown inFIG. 20, the connecting conductor282, the third pole piece213and the back gap piece217are formed. The connecting conductor282, the third pole piece213and the back gap piece217each are plating films of CoFe or CoNiFe and are 1 to 2 μm thick, for example.

Next, an insulating film255of Al2O3is deposited on the surface where the connecting conductor282, the third pole piece213and the back gap piece217have been formed, the insulating film255being 2 to 3 μm thick, for example. After that, the surfaces of the insulating film255, the third pole piece213, the back gap piece217and the connecting conductor282are polished by CMP. This CMP is performed so that the pole piece213and the back gap piece217become 0.2 to 0.6 μm thick.FIG. 21shows a state in which the CMP has been performed.

Next, as shown inFIG. 22, a magnetic film214to be a fourth pole piece214(seeFIG. 3) is formed by sputtering on the polished surfaces of the insulating film255, the third pole piece213and the back gap piece217, the magnetic film214being 0.5 to 1 μm thick, for example. The magnetic film214can be made of CoFeN (2.4 T), FeAlN, FeN, FeCo or FeZrN. In this embodiment, the magnetic film214is made of CoFeN (2.4 T). Moreover, a pattern-plating film250of NiFe, CoNiFe or the like is formed by a frame-plating method on the surface of the magnetic film214. The pattern-plating films250are formed right above the back gap pieces216and217and right above the third pole piece213.

Next, as shown inFIG. 23, the magnetic film214is etched by ion beam using the pattern-plating film250as a mask. After that, an insulating film256of alumina or the like is deposited 2 to 3 μm thick by sputtering and then, the insulating film256is polished and flattened by CMP to such a position that the pattern-plating film250is removed.FIG. 24shows a state in which this CMP process has been performed.

Next, as shown inFIG. 25, a gap film24is formed 0.06 to 0.1 μm thick on the flattened surface thus obtained by CMP. The gap film24is made of a non-magnetic metal material such as Ru, for example, and can be formed by sputtering or the like. After that, a second magnetic film221is formed on the surface of the gap film24and the flattened surface. The second magnetic film221is made of an HiBs material. Concretely, CoFe and CoFeN are particularly suitable among HiBs materials such as FeAlN, FeN, CoFe, CoFeN, FeZrN and the like. The second magnetic film221is formed, for example, 0.3 to 0.6 μm thick and is to be used as a seed film in the subsequent plating process for forming a third magnetic film.

After that, the third magnetic film222is formed by a frame-plating method using the second magnetic film221as a seed film. The third magnetic film222is made of NiFe (composition ratio, 55:45), CoNiFe (composition ratio, about 67:15:18, 1.9 T to 2.1 T), CoFe (composition ratio, 40:60, 2.3 T) or the like. The third magnetic film222is 3.5 to 4.0 μm thick. The third magnetic film222is formed so as to have a wide portion223and a narrow portion224as shown inFIG. 26. The wide portion223forms the second yoke portion and the narrow portion224forms the second pole portion P2.

Next, as shown inFIGS. 27 to 29, the whole wide portion223except the narrow portion224of the third magnetic film222is covered with a resist mask FR3. The resist mask FR3is formed to spread above the first coil231and the second coil232. Also, the resist mask FR3is formed to have an end face perpendicular to the surface of the narrow portion224.

Next, as shown inFIGS. 30 and 31, the area not covered with the resist mask FR3is etched by ion beam. Consequently, the seed film221and the narrow portion224of the third magnetic film222exposed around the resist mask FR3are trimmed.

The etching with the presence of the resist mask FR3may be stopped within the thickness of the seed film221, or may be continued to expose the gap film24, or may be continued to expose the gap film24and then expose the magnetic film214, which is a part of the first pole portion P1.

In the illustrated embodiment, referring toFIG. 31, the etching with the presence of the resist mask FR3is stopped within the thickness of the seed film221. Next, as shown inFIGS. 32 and 33, the resist mask FR3is removed and then etching without the resist mask is performed, continued to expose the magnetic film214. Consequently, the fourth pole piece214adjacent to the gap film24is trimmed at both sides in the width direction to have substantially the same width as the second pole portion P2. The indentations formed by the trimming have a bottom gradually increasing in thickness toward the fourth pole piece214. After that, a protective film258is formed (seeFIG. 2) and the manufacturing process is finished.

By the above-mentioned etching process, the surface of the narrow portion224is trimmed, lowered to a position lower than the surface of the wide portion223. This produces a sloping flare portion225that extends from the narrow portion224to the wide portion223, gradually increasing in width and its surface sloping upward away from the surface of the narrow portion224to the surface of the wide portion223.

Consequently, a three-dimensional difference in level by the sloping flare portion225is formed between the surface of the narrow portion224forming the second pole portion P2and the surface of the wide portion223. The advantage of this three-dimensional difference in level is as already described.

Now, a pole trimming process is described in more detail.

The pole trimming process is required to make the first pole portion P1and the second pole portion P2equal in width to each other and consequently prevent expansion of an effective write track width. Referring toFIGS. 34 and 35, the resist mask FR3is open at a part of the third magnetic film222including the narrow portion224and covers the whole wide portion223of the third magnetic film222and the coil. In this state, the surface of the narrow portion224is trimmed by ion beam and as a consequence, portions of the magnetic film213around the resist mask FR3is also etched correspondingly to the trimming depth of the narrow portion224.

Referring toFIG. 35, the resist frame FR3rises at the substantially same position with the flare point FP1in the rear of the ABS (in the coil side). Consequently, there is no possibility of the flare point FP1varying in the trimming process shown inFIGS. 34 and 35. This assures a constant minimal value of the distance from the ABS to the flare point FP1in a thin film magnetic head and consequently assures the overwrite characteristic.

Next, as shown inFIGS. 36 and 37, the resist mask FR3is removed and then the second magnetic film221used as a seed film is etched by ion beam using the third magnetic film222as a mask. In the etching process of the second magnetic film221, the resist mask FR3has been already removed and so, there is no possibility that metal particles resulting from the etching of the second magnetic film221might be deposited on a side end face of the resist mask with resultant deposit on the narrow portion224to be the second pole portion P2. Consequently, a narrowed track width, for example, 0.2 μm or less is achieved.

As shown inFIGS. 38 and 39, the trimming is continued to expose the magnetic film213, which is the top layer of the first pole portion P1. As a result, the first pole portion P1and the second pole portion P2are made to have the same track width, which prevents expansion of an effective write track width.

With regard to the quantity of trimmed portion of the third magnetic film222, trimming quantity on the surface of the third magnetic film222is larger than that on the both sides of the pole portion. The reason is that: on the surface of the third magnetic film222, there is no obstacle to the ion beams while on the both sides of the pole portion, the pole portion itself acts as an obstacle. Consequently, a structure having a three-dimensional difference in level is obtained.

Now, advantages of a trimming method according to the present invention are described in comparison with a conventional trimming method.

FIG. 40is a plan view showing a trimming method according to the present invention, andFIG. 42is a diagram showing a state in which the trimming shown inFIG. 40has been performed.FIG. 40is a diagram showing the process shown inFIGS. 35 and 36as a plan view. Referring toFIG. 40, the resist frame FR3rises at the substantially same position with the flare point FP1in the coil side (in the rear of the ABS). The position at which the resist frame FR3rises is not necessarily the same position with the flare point FP1and may be in the vicinity of the flare point FP1.

In the trimming method of the present invention, as the resist frame FR3rises at the rear of the ABS (in the coil side), there is no possibility of the flare point FP1varying in the trimming process shown inFIG. 40. This assures a constant minimal value of the distance from the ABS to the flare point FP1in a thin film magnetic head and consequently assures the overwrite characteristic.

FIG. 41is a plan view showing a conventional trimming method andFIG. 43is a plan view showing a state in which the trimming ofFIG. 41has been performed. In the conventional trimming method shown inFIG. 41, a trimming mask FR3is formed so as to surround a third magnetic film222to be an upper yoke portion and cover a coil portion, not to cover the wide portion223to be the upper yoke and the narrow portion224to be the upper pole.

Due to the trimming mask FR3not covering the wide portion223and the narrow portion224, ion beams trim a sloping flare portion225, which extends, gradually increasing in width, from the narrow portion224to be the upper pole portion to the wide portion223to be the upper yoke, so that the flare point FP1, at which the third magnetic film222begins to increase in width, backs to point FP2, with the increased distance B from the ABS to the flare point FP2as shown inFIG. 43. Distance B is larger than distance A (B>A).

The flare point backing described above reduces the magnetic volume, with degradation in the overwrite characteristic. The reason is that the closer the flare point FP1is to the ABS in the sloping flare portion225, the more excellent over-write characteristic is obtained. The flare point must be made close to the ABS, especially in the case of a track width of 0.2 μm or less.

In the conventional trimming method, another problem arises in addition to the flare point backing due to the above-mentioned reason. The problem is described with reference toFIGS. 44 to 47.

FIG. 44is a diagram showing a pole structure obtained by a trimming method of the present invention, andFIG. 45is a diagram showing a pole structure obtained by a conventional trimming method.

In the trimming method of the present invention, as shown inFIG. 44, a resist mask is removed and after that the whole including a pole portion and a seed film is trimmed by ion beam. In this step, as the resist mask FR3has been already removed, it is possible to apply ion beam at a relatively small angle of 30 to 45 degrees. Consequently, accurate control on the track width of a pole portion is achieved.

In the prior art, a trimming mask FR3is formed so as to surround a third magnetic film222to be the upper yoke and cover a coil portion, not to cover the third magnetic film222and the upper pole. As a result, when the magnetic film213is trimmed by ion beam, metal particles scattered by the ion beam trimming are deposited on the side walls of the upper pole as shownFIG. 45(see the deposit films DP1, DP2). To obtain a specified track width, the deposit films DP1and DP2must be removed. To remove the deposit films DP1and DP2, ion beams must be applied at a large angle of 50 to 75 degrees. As shown inFIG. 46, the ion beam irradiation at a large angle causes the narrower magnetic films222and221, which form the upper pole.

Moreover, the ion beam irradiation at a large angle gives the pole a taper angle to reduce the pole in width from the flare point toward the ABS. is gradually reduced, and this causes a problem of individual magnetic heads varying in track width on the ABS.

And while a narrow-track structure might be achieved by applying a semiconductor process technique on a flat pole structure to perform a submicron process on a pole portion, the surface of a flare portion expanding in width from the pole portion toward the yoke portion forms the same plane as the surfaces of the pole portion and yoke portion, causing problems that, in a write operation, the magnetic flux leaked from a side of the flare portion might erase a magnetic record on an adjacent track in a magnetic recording medium (side erase phenomenon), give a magnetic record to an adjacent track in a magnetic recording medium (side write phenomenon), or the like. Due to these problems, it is difficult to perform an accurate track control of 0.2 μm or less, and consequently it is impossible to achieve a high surface recording density of 100 Gb/p or more.

From the above description, it is apparent that the present invention can solve these problems of the conventional trimming method.

Embodiment 2 relates to a method for manufacturing a thin film magnetic head shown inFIGS. 7 and 8.FIGS. 47 to 65show a process of manufacturing the same. It is notified in advance that processes illustrated inFIGS. 47 to 63are also performed on a wafer.

(A) Process Leading to a State ofFIG. 47.

Referring toFIG. 47, on an insulating film16deposited on a base body15there are formed a first shield film31, a read element3, an insulating film32, a second shield film33, an insulating film34and a first magnetic film211by means of publicly known processes.

The first magnetic film211can be made of a plating film of NiFe (80%:20%), NiFe (45%:55%) or CoNiFe. The first magnetic film211may be made of a sputtering film of FeAlN, FeN, FeCo, CoFeN, FeZrN or the like with a thickness of 0.5 to 0.6 μm.

After that, an insulating film251is formed, for example, 0.2 μm thick on the flat surface of the first magnetic film211, the insulating film251having an area slightly larger than an area necessary for forming a coil, and then a seed film260is formed on the insulating film251. The seed film260is formed so as to cover the surface of the insulating film251and the surface of the first magnetic film211. The seed film260is made of a material suitable for a Cu-plating ground and formed 50 nm to 80 nm thick by a Cu-CVD process.

Next, a photoresist film is formed on the seed film260by applying a spin coating method or the like, and then is exposed through a mask having a coil pattern and developed. The photoresist film may be either positive photoresist or negative photoresist. The above-mentioned exposure process and development process form a resist frame. Next, a selective Cu-plating process is performed so that a first coil231is grown to be 3 to 3.5 μm thick on the seed film260inside the coil forming pattern.FIG. 47shows a state in which the above-mentioned selective Cu-plating process has been performed.

(B) Process Leading to a State ofFIG. 48

In a process leading from the state ofFIG. 47to the state ofFIG. 48, a photolithography process for forming a pole piece and a back gap piece is performed so that a resist frame for forming the pole piece and the back gap piece is formed.

Next, a selective plating process is performed so that the pole piece and the back gap piece are formed 3.5 μm thick on the first magnetic film211, and then the resist frame is removed by means of chemical etching or the like. Consequently, as shown inFIG. 48, the pole piece212and the back gap piece216are formed with a space between them on one surface of the first magnetic film211. The pole piece212and the back gap piece216can be made of CoNiFe (composition ratio, 67:15:18, 1.8 to 1.9 T) or FeCo (composition ratio, 60:40, 2.4 T).

(C) Process Leading to a State ofFIG. 49

In a process leading from the state ofFIG. 48to the state ofFIG. 49, a photoresist film RS4covering the first coil231, the pole piece212and the back gap piece216is formed, and then the first magnetic film211is selectively etched by ion beam etching (hereinafter, referred to as IBE), using the photoresist film RS4as a mask.

(D) Process Leading to a State ofFIG. 50

In a process leading from the state ofFIG. 49to the state ofFIG. 50, the resist cover RS4shown inFIG. 49is removed and then, as shown inFIG. 50, an insulating film252is deposited on the surfaces and side faces of the insulating film251, the first coil231, the second pole piece212and the back gap piece216. Concretely, the insulating film252is formed 0.05 to 0.15 μm thick by an Al2O3—CVD process. The insulating film is formed under a low-pressure atmosphere at a temperature not less than 100 C. In case of forming the insulating film252as an Al2O3film, it is possible to adopt an alumina-CVD film forming method of spraying Al(CH3)3and AlCl3in an alternate and intermittent way under a low-pressure atmosphere of H2O, N2, N2O or H2O2.

Next, a seed film261is deposited on the surface of the insulating film252. The seed film261can be formed as a Cu-sputtering film of 50 nm in thickness, a Cu-CVD film stack of 50 nm in thickness or the like.

(E) Process Leading to a State ofFIG. 51

In a process leading from the state ofFIG. 50to the state ofFIG. 51, a plating film232to be a second coil is formed, for example, 3 to 4 μm thick on the seed film261by a frame-plating method. The plating film232comprises Cu as its main constituent and is formed by a selective plating method. The seed film261not covered with the plating film232is removed by wet etching using dilute hydrochloric acid, dilute sulfuric acid, copper sulfate or the like, or by dry etching such as ion milling or the like.

After that, an insulating film253of Al2O3is formed so as to cover the plating film232and the area not covered with the plating film232. The insulating film253is formed as a sputtering film of 4 to 6 μm in thickness.

(F) Process Leading to a State ofFIG. 52

In a process leading from the state ofFIG. 51to the state ofFIG. 52, the insulating film253and the plating film232are polished and flattened by CMP. Consequently, a second coil232of a spiral pattern is obtained, insulated from the first coil231by the insulating film252. In the CMP, the surfaces of the pole piece212, the back gap piece216and the insulating film253are also polished so as to form the same plane as the surfaces of the first coil231and the second coil232.

(G) Process Leading to a State ofFIG. 53

In a process leading from the state ofFIG. 52to the state ofFIG. 53, as shown inFIG. 53, an insulating film254covering the surfaces of the first coil231and the second coil232is formed thereon. The insulating film254is made of Al2O3and formed, for example, 0.2 μm to 0.5 μm in thickness.

Next, a reactive ion etching (RIE) process or an ion milling process is performed on the insulating film254to form openings for a third pole piece213and a back gap piece217(seeFIGS. 7 and 8). After that, plating is performed to form the third pole piece213and the back gap piece217. After the third pole piece213and the back gap piece217are formed, the resist frame is removed. The third pole piece213and the back gap piece217each are a plating film of CoFe or CoNiFe (2.1 to 2.3 T) and have a film thickness of 1 to 2 μm.

Next, an insulating film255of Al2O3is deposited, for example, 1 to 2 μm in thickness on the surface where the third pole piece213and the back gap piece217have been formed, and then the surfaces of the insulating film255, the third pole piece213and the back gap piece217are polished by CMP.

(H) Process Leading to States ofFIGS. 54 and 55

In a process leading from the state ofFIG. 53to the state ofFIG. 54, a magnetic film214is formed 0.5 to 1.0 μm thick on the polished surfaces of the insulating film255, the third pole piece213and the back gap piece217. The magnetic film214can be made of a plating film of CoFeN (2.4 T) or a sputtering film of FeAlN, FeN, FeCo or FeZrN. After that, a mask250, which is a pattern-plating film of NiFe or CoNiFe, is formed on the third pole piece213and the back gap piece217. And an IBE process with the mask250is performed on the magnetic film214so that the magnetic film214is patterned. Consequently, as shown inFIG. 55, a fourth pole piece214and a back gap piece218are formed.

In case of patterning the magnetic film214with the mask250of a pattern-plating film, ion beams are applied at 0 degree and 75 degrees, which provides selective patterning on the magnetic film214made of an HiBs material.

The magnetic film214can also be patterned by other methods. For example, an RIE process is applied onto the magnetic film214at a high temperature of 50 to 300 C under a halogen-based gas atmosphere of Cl2, BCl3+Cl2or the like, so that the magnetic film214is etched to 80% of its film thickness. The temperature in the RIE process is preferably 50 C or higher, more preferably 200 to 250 C. This temperature range provides a high-accuracy pattern.

Moreover, an etching profile can be accurately controlled by introducing O2into a Cl2-based gas. Specifically, as mixing O2with a BCl3+Cl2gas makes it possible to remove a deposit of a residual boron gas completely, an extremely accurate control over the etching profile is achieved.

Moreover, the use of an etching gas obtained by mixing a CO2with a Cl2gas, a BCl3+Cl2gas or a gas having O2mixed with a Cl2gas or a BCl3+Cl2gas increases the etching rate of RIE, and consequently improves the selection ratio with a mask material by 30 to 50%.

After a part of the magnetic film214, for example, 80% part is etched as described above, an additional ion beam etching (hereinafter, referred to as IBE) is applied onto the remaining magnetic film214. This IBE is applied at an angle of 40 to 70 degrees, for example.

As described above, by patterning the magnetic film214with the mask250made of a pattern-plating film of NiFe or CoNiFe, the fourth pole piece214with high accuracy is formed. Consequently, a throat height defined by the fourth pole piece214is controlled with high accuracy. For example, the throat height can be controlled to be 0.1 to 0.5 μm or. 0.2 to 0.7 μm with grate freedom. Consequently, a thin film magnetic head with a quick rise of a write current and excellent overwrite characteristic is obtained.

Moreover, as the throat height is defined by the fourth pole piece214of a thick HiBs material, write magnetic flux for giving a magnetic record to a medium can be concentrated at a pole end as reducing halfway leakage magnetic flux. Consequently, problems of side erase or side write can be solved.

(I) Process Leading to States ofFIGS. 56 and 57

In a process leading from the state ofFIG. 55to the state ofFIG. 56, an insulating film256of Al2O3is deposited by means of sputtering or the like. After that, as shown inFIG. 57, the surfaces of the insulating film256, the fourth pole piece214and the back gap piece218are polished and flattened by CMP.

(J) Process Leading to a State ofFIGS. 58 and 59

In a process leading from the state ofFIG. 57to the state ofFIGS. 58 and 59, the whole wide portion223of the third magnetic film222except the narrow portion224of the third magnetic film222is covered with a resist mask FR4. The resist mask FR4is formed to spread above the first coil231and the second coil232. Also, the resist mask FR4is formed to have an end face perpendicular to the surface of the narrow portion224.

Next, as shown inFIGS. 58 and 59, the area not covered with the resist mask FR4is etched by ion beam. Consequently, the seed film221and the narrow portion224of the third magnetic film222exposed around the resist mask FR4are trimmed.

The etching with the presence of the resist mask FR4may be stopped within the thickness of the seed film221, or may be continued to expose the gap film24, or may be continued to expose the gap film24and then expose the magnetic film214, which is a part of the first pole portion P1.

(K) Process Leading to a State ofFIGS. 60 and 61

In a process leading from the state ofFIGS. 58 and 59to the state ofFIGS. 60 and 61, the resist mask FR4is removed and then the etching without the resist mask is performed, continued to expose the magnetic film214. After that, a protective film258(seeFIG. 2) is deposited thereon and the manufacturing process is finished.

By the above-mentioned etching process, the surface of the narrow portion224is trimmed, lowered to a position lower than the surface of the wide portion223. This produces an sloping flare portion225that extends from the narrow portion224to the wide portion223, gradually increasing in width and its surface sloping upward away from the surface of the narrow portion224to the surface of the wide portion223.

Consequently, a three-dimensional difference in level by the sloping flare portion225is formed between the surface of the narrow portion224forming the second pole portion P2and the surface of the wide portion223. The advantage of this three-dimensional difference in level is as already described.

(L) Process Leading to a State ofFIGS. 62 and 63

In a process leading from the state ofFIGS. 60 and 61to the state ofFIGS. 62 and 63, IBE is performed using the third magnetic film222and the second magnetic film221as a mask so that the fourth pole piece214, which is a part of the first pole portion P1, is trimmed to a depth of 0.25 to 0.35 μm. After that, as shown inFIGS. 64 and 65, a protective film258is deposited 20 to 40 μm thick thereon. The deposition of the protective film258is made by sputtering.

The above-mentioned processes are performed on a wafer. After that, publicly known post-processes of cutting out a bar-shaped head assembly from the wafer, polishing for determining a throat height, processing ABS52,53and the like are performed.

Embodiment 3 is a process of manufacturing a thin film magnetic head shown inFIG. 9, and is illustrated inFIGS. 66 to 71. Processes, which have been illustrated and described in embodiment 1 or 2 and are also applied to embodiment 3, are referred to the description of embodiment 1 or 2 and the illustrations of the processes may be omitted.

(A) Process Leading to a State ofFIG. 66

On an insulating film16deposited on a base body15there are formed a first shield film31, a read element3, an insulating film32, a second shield film33, an insulating film34and a first magnetic film211by means of publicly known processes. After that, an insulating film251is formed on the flat surface of the first magnetic film211, the insulating film251having an area slightly larger than an area necessary for forming a coil. The insulating film251is formed so as to have openings in parts where a back gap portion and a pole portion are to be formed. After that, the second pole piece212and the first back gap piece216are formed in the openings.FIG. 66shows a state in which the second pole piece212and the first gap piece216have been formed.

(B) Process Leading to a State ofFIG. 67

After the process ofFIG. 66, a photolithography process is performed on one surface where the insulating film251has been formed, and a resist frame plating method is performed so that a first coil231is formed. Next, an insulating film252of photoresist is formed in the space between coil turns of the first coil231.

Next, an insulating film254of Al2O3is deposited, for example, 3 to 4 μm thick on the surface where the pole piece212and the back gap piece216have been formed, and then the surfaces of the insulating film254, the pole piece212and the back gap piece216are polished by CMP.FIG. 67shows a state in which the CMP has been performed.

(C) Process Leading to a State ofFIGS. 68 and 69

In a process leading from the state ofFIG. 67to the state ofFIGS. 68 and 69, the processes ofFIGS. 20 to 27are performed. First, a photolithography process is performed on one surface where the insulating film254has been formed, so that a resist frame for a connecting conductor282to be connected to the inner end281of the first coil231and a resist frame for the third pole piece213and the back gap piece217(seeFIG. 27) are formed, and then a frame-plating process is performed according to a pattern defined by the obtained resist frames. Consequently, the connecting conductor282, the third pole piece213and the back gap piece217are formed. The connecting conductor282, the third pole piece213and the back gap piece217each are a plating film of CoFe or CoNiFe and have a film thickness of 1 to 2 μm, for example (seeFIG. 20).

Next, an insulating film255of Al2O3is deposited on the surface where the connecting conductor282, the third pole piece213and the back gap piece217have been formed, and then the surfaces of the insulating film255, the third pole piece213, the back gap piece217and the connecting conductor282are polished by CMP. This CMP is performed so that the third pole piece213and the back gap piece217become 0.2 to 0.6 μm in thickness, for example (seeFIG. 21).

Next, a gap film24is formed 0.06 to 0.1 μm thick on the surface flattened by CMP (seeFIG. 25). The gap film24is made of a non-magnetic metal material such as Ru and formed by sputtering or the like. Next, a second magnetic film221is formed on the surface of the gap film24and the flattened surface. The second magnetic film221is made of an HiBs material. Concretely, CoFe and CoFeN are particularly suitable among HiBs materials such as FeAlN, FeN, CoFe, CoFeN, FeZrN and the like. The second magnetic film221is formed, for example, 0.3 to 0.6 μm thick and is to be used as a seed film in the subsequent plating process for forming a third magnetic film.

After that, the third magnetic film222is formed by a frame-plating method using the second magnetic film221as a seed film. The third magnetic film222is made of NiFe (composition ratio, 55:45), CoNiFe (composition ratio, nearly 67:15:18, 1.9 T to 2.1 T), CoFe (composition ratio, 40:60, 2.3 T) or the like. The third magnetic film222is 3.5 to 4.0 μm thick. The third magnetic film222is formed so as to have a wide portion223and a narrow portion224(seeFIG. 26). The wide portion223forms a second yoke portion and the narrow portion224forms a second pole portion P2.

Next, the whole wide portion223of the third magnetic film222except the narrow portion224of the third magnetic film222is covered with a resist mask FR5(seeFIGS. 27 to 29). The resist mask FR5is formed to spread above the first coil231. Also, the resist mask FR5is formed is formed to have an end face perpendicular to the surface of the narrow portion224.FIGS. 68 and 69show a state in which the resist mask FR5has been formed.

Next, as shown inFIGS. 68 and 69, the area not covered with the resist mask FR5is etched by ion beam. Consequently, the seed film221and the narrow portion224of the third magnetic film222exposed around the resist mask FR3are trimmed.

The etching with the presence of the resist mask FR5may be stopped within the thickness of the seed film221, or may be continued to expose the gap film24, or may be continued to expose the gap film24and then expose the magnetic film213, which is a part of the first pole portion P1.

In the illustrated embodiment, referring toFIG. 69, the etching with the presence of the resist mask FR5is stopped within the thickness of the seed film221. Next, as shown inFIGS. 70 and 71, the resist mask FR5is removed and then the etching is performed, continued to expose the magnetic film214. After that, a protective film258(seeFIG. 2) is deposited thereon and the manufacturing process is finished.

By the above-mentioned etching process, the surface of the narrow portion224is trimmed, lowered to a position lower than the surface of the wide portion223. This produces a sloping flare portion225that extends from the narrow portion224to the wide portion223, gradually increasing in width and its surface sloping upward away from the surface of the narrow portion224to the surface of the wide portion223.

Consequently, a three-dimensional difference in level by the sloping flare portion225is formed between the surface of the narrow portion224forming the second pole portion P2and the surface of the wide portion223. The advantage of this three-dimensional difference in level is as already described.

3. Magnetic Head Device and a Magnetic Recording/reproducing Apparatus

The present invention also discloses a magnetic head device and a magnetic recording/reproducing apparatus. Referring toFIGS. 72 and 73, a magnetic head device according to the present invention comprises a thin film magnetic head400shown inFIGS. 1 to 9and a head supporting device6. The structure of the head supporting device6is as follows: a flexible member62made of a metal sheet is attached to a free end of a supporting member61made of a metal sheet, the free end being at one end in the longitudinal direction; and the thin film magnetic head400is attached to the lower surface of the flexible member62.

Specifically, the flexible member62comprises: two outer frame portions621and622extending nearly in parallel with the longitudinal axial line of the supporting member61; a lateral frame623for connecting the outer frame portions621and622at the end which is distant from the supporting member61; and a tongue-shaped piece624extending nearly from the middle part of the lateral frame623nearly in parallel with the outer frame portions621and622and having a free end at the tip. One end of the flexible member62opposite to the lateral frame623is joined to the vicinity of the free end of the supporting member61by means of welding or the like.

The lower face of the supporting member61is provided with a loading projection625in the shape of a hemisphere, for example. This loading projection625transmits load from the free end of the supporting member61to the tongue-shaped piece624.

The thin film magnetic head400is joined to the lower surface of the tongue-shaped piece624by means of adhesion or the like. The thin film magnetic head400is supported so as to allow pitching and rolling actions.

A head supporting device to which the present invention is applied is not limited to the above-described embodiment. The present invention can also be applied to head supporting devices which have been proposed up to now or will be proposed in the future. For example, the present invention can be applied to a head supporting device obtained by integrating the supporting member61and the tongue-shaped piece624by a flexible high-molecular wiring sheet such as a TAB tape (TAB: tape automated bonding), and a head supporting device having a publicly known conventional gimbals structure.

Next, referring toFIG. 74, a magnetic recording/reproducing apparatus according to the present invention comprises a magnetic disk71provided so as to be capable of turning around an axis70, a thin film magnetic head72for recording and reproducing information on the magnetic disk71and an assembly carriage device73for positioning the thin film magnetic head72on a track of the magnetic disk71.

The assembly carriage device73comprises a carriage75capable of turning around an axis74and an actuator76composed of, for example, a voice coil motor (VCM) for turning this carriage75, as main components.

The base portion of a plurality of driving arms77stacked in the axial direction of the axis74is attached to the carriage75, and a head suspension assembly78with a thin film magnetic head72is fixedly joined to the tip of each driving arm77. Each head suspension assembly78is joined to the tip of a driving arm77so that a thin film magnetic head72on the tip of the head suspension assembly78faces the surface of each magnetic disk71.

The driving arm77, head suspension assembly78and thin film magnetic head72form the magnetic head device described with reference toFIGS. 72 and 73. The thin film magnetic head72has the structure shown inFIGS. 1 to 9. Thus, the magnetic recording/reproducing apparatus shown inFIG. 86exhibits the action and effect described with reference toFIGS. 1 to 9.

Although the contents of the present invention have been concretely described above with reference to the preferred embodiments, it is obvious that people in this field can take various variations on the basis of the basic technical idea and teachings of the present invention.