JP3217008B2 - Method of manufacturing magnetoresistive head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head provided with a magnetoresistive element (hereinafter, referred to as an MR element) and an inductive element, a method of manufacturing the same, and a magnetic storage device using the magnetoresistive head. .

[0002]

2. Description of the Related Art For example, a read-only magnetic head mounted on a hard disk drive or the like has a characteristic that a read sensitivity does not depend on a peripheral speed, and thus has a magnetoresistive effect head (hereinafter referred to as an MR head). Is commonly used.

[0003] An MR head uses a film having a magnetoresistive effect, such as NiFe or NiCo (hereinafter referred to as an MR film), on a magnetic recording medium by utilizing the property that the resistance value changes depending on the direction and intensity of an applied magnetic field. This is a head for reading recorded magnetization information.

The structure of a conventional MR head will be described with reference to FIG. 2, which is a view of the MR head viewed from the side facing the medium. In the MR head, an insulating film 22 as a lower gap film is provided between a lower shield magnetic body (hereinafter referred to as a lower shield) 11 and the MR element 12, and a magnetic layer is provided between the lower shield 11 and the MR element 12. An underlying magnetic gap that has no body properties is formed. Also, MR
An insulating film 23 is provided as an upper gap film between the element 12 and the upper shield magnetic body (hereinafter referred to as an upper shield) 13, and an upper magnetic gap is formed between the MR element 12 and the shield 13. . The lower and upper shields have the effect of absorbing the signal magnetic field from the recording medium and limiting the magnetic sensing area of the element between these shields.
It is an essential component for increasing the resolution of the MR head.

With the recent increase in recording density, the miniaturization of the MR head has been remarkably reduced, and the magnetic read / read width has been approaching the submicron order, and the MR element has a depth direction from the medium resistance surface (to the medium opposing surface). Length in the vertical direction)
MR height) is less than 0.5 μm.

[0006] The MR height is determined by cutting a head from a wafer in a bar state and performing mechanical polishing in that state.

At that time, apart from the actual device, a monitor element 2 for monitoring the resistance value at the time of manufacture in order to determine the polishing amount is prepared. The configuration of the monitor element 2 is the same as that of the MR element 12. Here, the accuracy of the MR height depends on the accuracy of the monitor element 12.

At this time, the lower shield 11 has a thickness of 1-2 μm.
The monitor element 2 is formed simultaneously with the patterning of the MR element 12.

The MR element 12 is formed in the upper layer of the lower shield 11, but the monitor element 2 is present in a region where the lower shield 11 does not exist. At this time, if the focus is set on the MR element 12, the monitor element 2 will be out of focus and the monitoring accuracy will be reduced.

[0010]

In order to solve the above problems, the surface on which the MR element 12 is formed and the monitor element 2
It is desirable that the height of the surface on which the substrate is formed from the substrate 1 be substantially the same.

In order to make the surface height approximately the same, it is conceivable to form a lower shield in the region where the monitor element 2 is formed in the same manner as the surface where the MR element is formed. Since a groove is formed between the lower shield 11 and the lower side, unnecessary steps are increased, which causes an increase in the thickness variation of the resist, and causes a problem in photolithography technology.

As a method of embedding the lower shield,
Japanese Patent Application Laid-Open No. 6-68426 discloses an etch back method.

In the embedding method by the etch-back method, after patterning the lower shield magnetic material, an insulating film such as alumina or SiO2 having a film thickness not less than the thickness of the lower shield magnetic material is formed, and then a photovoltaic material mainly composed of novolak resin is formed. Apply a resist to reduce steps. Thereafter, a magnetic film is buried as a flat lower shield by performing dry etching such as ion milling in a vacuum under the condition that the etching rates of the insulating film and the photoresist become substantially the same.

However, the flattening process of the pattern by the above-described method requires not only an increase in the number of steps but also a high throughput due to the etching in the order of μm in order to eliminate the steps of the shield in the order of μm.
It is considered difficult to apply to mass production process.

[0015]

In order to solve the above-mentioned problems, in the MR head of the present invention, a lift-off process is used. To reduce

The magnetoresistive head manufactured by the manufacturing method of the present invention comprises at least a substrate, a first insulating film, a patterned lower shield, a lower gap film, a magnetoresistive element (hereinafter, MR element), and an upper gap film. , And an upper shield sequentially stacked, wherein a second insulating film, the lower gap film, and a resistance during manufacturing are formed on the first insulating film in a region where the lower shield does not exist. A monitor element for measuring a value is formed by sequentially laminating, and a height of a surface of the lower gap film forming the monitor element from a surface of the substrate, and a surface of the lower gap film forming the MR element Are substantially equal in height from the surface of the substrate.

According to the method of manufacturing a magnetoresistive effect head of the present invention, a first step of forming a magnetic film made of a magnetic material;
It has a shape of a lower shield to be formed when viewed from a direction facing a surface on which a film is formed, has a stencil shape as a cross section, and has a width of the stencil shape in the magnetic film formed in the first step. A second step of forming a photoresist pattern in contact with a smaller surface, and a third step of forming the lower shield by removing a portion of the magnetic film that is not covered with the photoresist pattern by using a dry etching method. A fourth step of forming an insulating film made of an oxide to have a thickness equivalent to that of the magnetic film, a fifth step of removing the photoresist pattern, and the presence of the lower shield. A sixth step of forming an MR element on the region and a monitor element for measuring a resistance value at the time of manufacturing on the region where the insulating film is present, respectively.

[0018]

FIG. 1 shows the structure of an MR head according to the present invention. FIG. 1 is a diagram of the MR head viewed from the side facing the medium.

In FIG. 1, a substrate 1 is made of Al 2 O 3 —Ti
Made of a ceramic material such as C.
An insulating film 21 such as O3 was formed. Next, a magnetic material such as NiFe or AlSiFe is formed in a thickness of about 1 to 3 μm by a sputtering method or an electrolytic plating method,
The lower shield 11 was formed by patterning using a photolithography technique. Then, after the insulating film 25 is formed and the lower shield 11 is embedded, Al is used as a lower gap film.
An insulating film 22 made of an oxide film such as 2 O3 or SiO2 or a nitride film such as SiN is formed, and an MR element 12 is formed on an upper surface thereof. Next, the electrode 31 is formed in a state of being in contact with the MR element. Further, an upper gap film is formed so as to cover them by using an insulating film 23 similar to the insulating film 22 as the lower gap film, and the upper shield 13 is formed thereon. At this time, the lower gap and the upper gap are defined by the thicknesses of the lower gap film (insulating film 22) and the upper gap film (insulating film 23). At this time, the upper shield (upper shield magnetic body) 13 has a function as a shield of the MR element 12 for reading data and a function as a pole of a write element including the magnetic film 14 and the upper shield magnetic body 13.

Next, a method of embedding the lower shield 11 is shown in FIG. First, after an insulating film 21 such as Al2 O3 is formed on the substrate 1, NiFe or Al is formed on the insulating film 21 to a predetermined thickness by a sputtering method or an electrolytic plating method.
A magnetic material such as SiFe is deposited.

After the lower shield 11 is formed as shown in FIG. 3A by depositing a magnetic material, a photoresist pattern 41 having a lower shield shape to be formed and a stencil cross section is simply formed. It is formed as shown in FIG. 3B by a layer resist or a multilayer resist method. At this time, the stencil-shaped photoresist pattern 4
1 and the height h of the space surrounded by the magnetic film is the insulating film 2 to be formed.
The thickness of the photoresist is preferably about 0.5 times to 1 time, and the thickness of the entire photoresist is preferably twice or more the thickness of the insulating film 25 to be formed.

Here, a stencil-shaped photoresist 4
The method 1 will be described.

After a photoresist (hereinafter referred to as PR) is applied and baked, a portion where the PR is to be left is exposed to UV (ultraviolet) using a photomask (not shown). At this time, the cross-sectional shape of the PR after development changes depending on the exposure amount. When the absorption curve of the PR light at the time of the initial exposure is used, a portion far from the light-irradiating surface, that is, a lower region of the PR has a small exposure amount, and thus forms a stencil shape. If the initial exposure amount is large, the PR approaches a rectangle,
The smaller the height, the higher the height h of the space.

Next, baking is performed to cause a thermal crosslinking reaction in the exposed area. Where the thermal crosslinking reaction occurs, it becomes hardly soluble in the developer. Next, the unexposed portion is made soluble in the developing solution by irradiating the entire surface with light. Thereafter, by developing, only the portion first irradiated with light remains.

The cross-sectional shape of the PR generated after development is controlled by the exposure amount of the initial exposure as described above.

After performing the photoresist patterning,
When a portion of the magnetic film (the lower shield 11) that is not covered by the photoresist pattern 41 is removed by using a dry etching method such as ion milling, the result is as shown in FIG.

After removing the excess magnetic film by ion milling or the like, an insulating film 25 made of an oxide such as Al 2 O 3 or SiO 2 is formed by a sputtering method as shown in FIG. The thickness at this time is desirably the same as the thickness of the magnetic film.

When the stencil-shaped photoresist pattern 41 according to the present invention is used to fill with alumina (Al 2 O 3) after the lower shield milling, as shown in FIG. Even so, since the photoresist pattern 41 is undercut, that is, there is a cut near the end of the lower shield, the entire pattern is not covered with alumina. Therefore, the photoresist pattern 41 can be easily peeled off (lifted off), and it is possible to prevent alumina adhered to the side wall of the photoresist pattern 41 from remaining as burrs. Further, since the alumina sputtered film that has penetrated into the undercut portion of the photoresist pattern 41 also has a gentle taper, it is possible to stably apply the photoresist film thickness in the subsequent photolithography process.

After the insulating film 25 is formed, the photoresist pattern 41 is removed (lifted off) to obtain a structure shown in FIG.
A shape in which the step between the element formation surface and the monitor formation surface is reduced as shown in (e) can be obtained.

When the lower shield 11 is formed by a conventional method, it is usually formed by the steps shown in FIG. First, as shown in FIG. 4A, a magnetic material is formed in a predetermined thickness in the same manner as in the present invention, and the lower shield 11 is formed.
To form Next, as shown in FIG. 4B, a photoresist pattern 42 having a shape of a lower shield is formed by the photoresist, and a portion of the magnetic film that is not covered by the photoresist pattern 42 is removed by ion milling or the like. I do. After removing the magnetic film, the lower shield 11 is formed by removing the photoresist.
In this method, a step corresponding to the thickness of the magnetic film is generated between the element formation surface and the monitor formation surface.

When the insulating film 25 is to be buried with alumina using the photoresist pattern of the prior art after the lower shield milling, FIG.
It is very difficult to remove the photoresist pattern 42 because the entire photoresist pattern 42 is covered by the sputtered alumina as shown in FIG. Even if the photoresist pattern 42 could be peeled off, the alumina adhered to the side wall of the photoresist pattern 42 could not be removed.
As shown in (c), the burrs remain, which causes a variation in the thickness of the photoresist in a subsequent photolithography process.

For example, in the present invention, when a magnetic film having a thickness of 2 μm is formed, Al 2 O 3 having a thickness of 2 μm is formed after ion milling, and the photoresist is removed. Can be reduced to 0.2 [mu] m or less, which is 1/10 or less of the film thickness, but a step of 2 [mu] m occurs in the conventional method.

[0033]

When the lower shield is formed, the step between the element formation surface and the monitor formation surface can be reduced to 1/10 or less by adding one step to the conventional method.
Higher throughput can be obtained than in the etch back method.

Further, since the step between the monitor formation surface and the element formation surface is reduced, the accuracy of the monitor element for determining the MR height by the photolithography technique can be improved.

Further, since the variation in the thickness of the photoresist due to the influence of the step is reduced, the patterning accuracy of the MR element is also improved.

[Brief description of the drawings]

FIG. 1 is a view showing a structure of a medium facing surface of a magnetic head in which a lower shield magnetic body of the present invention is flattened.

FIG. 2 is a view showing a structure of a medium facing surface of a magnetic head according to the related art.

FIG. 3 is a view showing a structure of a medium facing surface in each step of the magnetic head manufacturing method of the present invention. FIG. 3A is a configuration diagram when a magnetic film is formed. FIG. 3B is a configuration diagram when a photoresist pattern is formed.
FIG. 3C is a configuration diagram after removing a portion of the magnetic film that is not covered with the photoresist pattern. FIG. 3 (d)
FIG. 2 is a configuration diagram when an insulating film 25 is formed. FIG.
(E) is a configuration diagram after the photoresist pattern is removed.

FIG. 4 is a diagram showing a structure of a medium facing surface in each step of a magnetic head manufacturing method according to a conventional technique. FIG.
(A) is a configuration diagram when a magnetic film is formed. FIG.
(B) is a configuration diagram when a photoresist pattern is formed. FIG. 4C is a configuration diagram after a portion of the magnetic film that is not covered with the photoresist pattern is removed.
FIG. 4D is a configuration diagram after the photoresist pattern is removed.

FIG. 5 is a diagram showing a structure of a medium facing surface when flattening is performed by a conventional photoresist pattern. FIG. 5A is a configuration diagram after lower shield milling. FIG. 5B is a configuration diagram after the alumina sputtering.
FIG. 5C is a configuration diagram after the photoresist is stripped.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Monitor element 11 Lower shield 12 MR element 13 Upper shield 14 Magnetic film 21 Insulating film 22 Insulating film 23 Insulating film 24 Write gap film 25 Insulating film 26 Overcoat 31 Electrode 41 Photoresist 42 Photoresist

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

Claims (2)

(57) [Claims] A first step of forming a magnetic film made of a magnetic material, and a shape of a lower shield to be formed when viewed from a direction facing a surface on which the film is formed; and a stencil shape in cross section. A second step of forming a photoresist pattern in which the smaller surface of the stencil shape is in contact with the magnetic film formed in the first step; and covering the photoresist pattern using a dry etching method. A third step of forming the lower shield by removing the portion of the magnetic film that is not present, and a fourth step of forming an insulating film made of an oxide to a thickness equivalent to that of the magnetic film. A fifth step of removing the photoresist pattern, a monitor for measuring an MR element on a region where the lower shield exists, and a resistance value at the time of manufacture on a region where the insulating film exists. Method of manufacturing a magnetoresistive head which comprises a sixth step of forming a device, respectively. 2. The method according to claim 1, wherein the first step is performed by a process selected from the group consisting of sputtering and electrolytic plating.
e and a film selected from the group consisting of AlSiFe, and in the second step, the height h of the space surrounded by the stencil-shaped photoresist pattern and the magnetic film is the film thickness of the insulating film. The thickness of the photoresist at a portion in contact with the insulating film is about twice or more the thickness of the insulating film;
Claims a dry etching method steps employed ion milling, the fourth step is characterized by formed by Al ₂ O ₃ and sputtering at least one of an oxide of SiO ₂ 1 A method for manufacturing the magnetoresistive head according to any one of the preceding claims.