JP2005108348A - Method for manufacturing perpendicular magnetic recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED To make it possible to accurately form a cross section of a write main pole in an inverted trapezoidal shape, to prevent manufacturing variations, and to efficiently manufacture a high-precision perpendicular magnetic recording head.
In a method of manufacturing a perpendicular magnetic recording head comprising: a magnetic yoke having a main magnetic pole facing a recording medium; a write magnetic pole having a coil wound around the magnetic yoke; and a reproducing element. A step of forming a main magnetic pole layer 20 to be a main magnetic pole, a step of forming a barrier layer 22 made of a nonmagnetic material on the surface of the main magnetic pole layer 20, and a focused ion beam on the barrier layer 22 and the main magnetic pole layer 20 And forming a tip end portion of the main magnetic pole 10 having a cross-sectional shape of an inverted trapezoid.
[Selection] Figure 3

Description

  The present invention relates to a method of manufacturing a perpendicular magnetic recording head, and more particularly to a method of manufacturing a perpendicular magnetic recording head in which a main magnetic pole tip is formed in an inverted trapezoidal cross-sectional shape.

A magnetic head used in a conventional magnetic disk device records information by magnetizing the medium within the medium surface of the recording medium, whereas a perpendicular magnetic recording head magnetizes the medium perpendicular to the medium surface to record information. Record. In order to magnetize the medium perpendicular to the medium surface as described above, the perpendicular magnetic recording head includes a main magnetic pole disposed to face the medium surface and a return yoke for returning the magnetic lines of force that have passed through the medium.
In a magnetic disk device using a perpendicular magnetic recording head, information can be recorded at a much higher density than a magnetic head based on in-plane magnetization. It is necessary to form an end face (tip portion) facing the medium with a very narrow width (about 0.1 μm).

  FIG. 6 shows the end face shape of the main pole 10 of the perpendicular magnetic recording head. As shown in the figure, the main magnetic pole 10 has an inclined side surface and a cross-sectional shape of an inverted trapezoid. The reason why the cross-sectional shape of the main magnetic pole 10 is formed in an inverted trapezoidal shape is to prevent side erasure when the magnetic head moves on the track. Is set to about 80 ° to 85 °. The upper surface of the main pole 10 (part A) is a part where information is recorded, and in order to record information with high precision, the upper surface edge of the main pole 10 needs to be formed at an acute angle. .

  FIG. 7 shows a conventional method for forming the main magnetic pole in such a fine and inverted trapezoidal shape, and shows a cross-sectional structure (substrate and reproducing element not shown) viewed from the side of the write magnetic pole. In FIG. 7A, a return yoke 12 made of a magnetic material is formed, a coil layer and a back closure layer are formed through an insulating layer 13, and these are patterned to form a coil 14 and a back closure 16. Further, after the insulating layer 17 is formed and planarized, the main magnetic pole thickening layer 18 made of a magnetic material is formed, and after the surface is flattened, the main magnetic pole layer 20 is formed and formed. Indicates. The main magnetic pole layer 20 is made of a magnetic material such as FeCo, and the main magnetic pole layer 20 covers the entire surface of the workpiece.

In FIG. 7B, in order to form the main pole 10 in a predetermined pattern by etching the main pole layer 20, a barrier layer 22 made of a nonmagnetic material such as Ta is formed on the surface of the main pole layer 20, and The state in which the resist layer 24 is formed is shown. The barrier layer 22 is for protecting the main magnetic pole 10 and making the edge of the main magnetic pole 10 have an acute angle when ion milling the main magnetic pole layer 20.
Next, the resist layer 24 is etched according to the shape of the main magnetic pole 10 to form a resist pattern 24a. FIG. 9 shows the planar shape of the resist pattern 24a. The resist pattern 24a is patterned so that a narrow portion 25 having a narrow width is formed as shown in the figure. The workpiece is cut so as to cross the narrow portion 25, and the cut end surface becomes the end surface (tip portion) of the main magnetic pole 10. The narrow width portion 25 is patterned to a width of about 1.0 μm, which is wider than the completed width of the main magnetic pole 10.

FIG. 7C shows a state in which the barrier layer 22 is etched by reactive ion etching (RIE) in order to etch the barrier layer 22 in accordance with the resist pattern 24a. FIG. 8A shows a state where the barrier layer 22 is etched as viewed from the cross-sectional direction of the narrow width portion 25 of the resist pattern 24a. Only the portion of the barrier layer 22 that is covered with the resist pattern 24 a by reactive ion etching remains on the surface of the main magnetic pole layer 20.
Next, ion milling is performed on the main magnetic pole layer 20 using the resist pattern 24a and the barrier layer 22 as a mask. FIG. 8B shows a state in which the main magnetic pole layer 20 is ion-milled, and ion milling is performed by fixing an angle of 45 ° from the right and left as shown.
FIG. 8C shows a state in which the main magnetic pole 10 is finally formed by ion milling. By ion milling from the oblique direction with respect to the main magnetic pole layer 20, the resist pattern 24a and the barrier layer 22 act as a shadow mask, and the side surface of the main magnetic pole 10 is formed into a tapered surface. FIG. 7D is a side cross-sectional view in a state where the main magnetic pole 10 is formed. The write magnetic pole is formed with the barrier layer 22 remaining on the upper surface of the main magnetic pole 10.

  The main magnetic pole of a perpendicular magnetic recording head must have a cross-sectional shape of an inverted trapezoid and a very narrow width of 0.1 μm. Conventionally, the main magnetic pole is formed by ion milling as described above. However, as can be seen from the processing steps shown in FIGS. 8B and 8C, in the case of the ion milling method, the resist pattern 24a is considered in consideration of the rate at which the main magnetic pole layer 20 is shaved by ion milling. The pattern width of the barrier layer 22 is much wider (1.0 μm) and thicker (2.0 μm) than the finished dimension (0.1 μm) of the main pole 10. For this reason, the variation of the width dimension of the main magnetic pole 10 after ion milling becomes large (3σ = 0.1), and the inclination angle of the side surface of the main magnetic pole 10 cannot be formed accurately, and the variation is about ± 10 °. There was a problem that it was inevitable that this would occur.

  Also, in recent perpendicular magnetic recording heads, it is a problem that an erase magnetic field is generated by the action of the residual magnetization of the main magnetic pole. In order to suppress the residual magnetization of the main magnetic pole and enable a high-speed response, the main magnetic pole is not limited to the FeCo layer. A multilayer structure having a Ru layer or a NiCr layer has been studied. In this way, when the main magnetic pole is made of different materials, the etching rates for reactive ion etching or ion milling of these magnetic materials or nonmagnetic materials are different, so that the main magnetic pole is formed into an inverted trapezoid shape by ion milling. When it is formed, there arises a problem that the edge of the main magnetic pole has a stepped shape, and there is a problem that the required accuracy as a magnetic head cannot be obtained.

  Therefore, the present invention has been made to solve these problems, and the object of the present invention is to make it possible to form the cross-sectional shape of the main pole in the write magnetic pole in an accurate inverted trapezoidal shape, resulting in manufacturing variations. Is to provide a method of manufacturing a perpendicular magnetic recording head capable of efficiently manufacturing a highly accurate perpendicular magnetic recording head.

In order to achieve the above object, the present invention comprises the following arrangement.
That is, in a method of manufacturing a perpendicular magnetic recording head including a magnetic yoke having a main magnetic pole facing a recording medium, a write magnetic pole having a coil wound around the magnetic yoke, and a reproducing element, the main magnetic pole A step of forming a main magnetic pole layer, a step of forming a barrier layer made of a nonmagnetic material on the surface of the main magnetic pole layer, and irradiating the barrier layer and the main magnetic pole layer with a focused ion beam, Forming a tip portion of the main magnetic pole having an inverted trapezoidal shape.

The barrier layer and the main magnetic pole layer are arranged so as to sandwich the main magnetic pole when the barrier layer and the main magnetic pole layer are irradiated with a focused ion beam to form the tip of the main magnetic pole having a cross-sectional shape of an inverted trapezoid. And etching to form an opening.
When the focused ion beam is irradiated to the barrier layer and the main magnetic pole layer to form the tip of the main magnetic pole whose cross-sectional shape is an inverted trapezoid, the focused ion beam is incident at an angle of 10 ° to 20 °. A step of irradiating and scanning is provided.
Forming a protective resist layer on the surface of the barrier layer after forming the tip of the main magnetic pole, patterning the protective resist layer to form a resist pattern covering the main magnetic pole, and masking the resist pattern And a step of removing a portion of the barrier layer excluding the main magnetic pole and the main magnetic pole layer.
And forming a protective layer covering the opening and the barrier layer after forming the tip of the main magnetic pole, forming a protective resist layer on the surface of the protective layer, and patterning the protective resist layer to form the main magnetic pole And a step of removing a portion of the barrier layer and the main magnetic pole layer excluding the main magnetic pole using the resist pattern as a mask.

  According to the method for manufacturing a perpendicular magnetic recording head according to the present invention, a barrier layer covering the main magnetic pole layer is provided, and the barrier layer and the main magnetic pole layer are irradiated with a focused ion beam to form the shape of the tip portion of the main magnetic pole. By this method, the cross-sectional shape of the tip (end face) of the main pole can be easily and accurately formed into an inverted trapezoidal shape, and the core width at the tip of the main pole is not varied and reliable. It is possible to manufacture a perpendicular magnetic recording head with high performance, and it is possible to mass-produce perpendicular magnetic recording heads with a high yield.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
1 to 4 are explanatory views showing a method of manufacturing a perpendicular magnetic recording head according to the present invention. FIGS. 1 and 2 are sectional views of the write magnetic pole as viewed from the side, and FIGS. Sectional drawing which looked at the magnetic pole from the front direction is shown.
FIG. 1A shows a state in which the return yoke 12, the insulating layer 13, the coil 14, the back closure 16, the main magnetic pole thickening layer 18, and the main magnetic pole layer 20 are formed. Except for the main magnetic pole layer 20, the structure of each layer is the same as that of the conventional perpendicular magnetic recording head shown in FIG. In the conventional example shown in FIG. 7, the main magnetic pole layer 20 is formed of FeCo. However, in this embodiment, the main magnetic pole layer 20 is formed of a laminated film of Ru and FeCo. The total thickness of the main magnetic pole layer 20 is 100 to 300 nm.

  Next, the barrier layer 22 is formed on the surface of the main magnetic pole layer 20 (FIG. 1B). The barrier layer 22 is used to protect the edge of the main pole so that it is formed at an acute angle when the main pole 10 is formed by the FIB (focused ion beam) method. The barrier layer 22 is made of nonmagnetic material such as Ta, Ti, or W. A material is formed on the surface of the main magnetic pole layer 20 by sputtering. In this embodiment, Ta is formed to a thickness of 200 nm. It is desirable to use a low-stress material for the barrier layer 22, and it is preferable to form the barrier layer 22 with a thickness of about 200 nm ± 50 nm in consideration of the thickness removed by the FIB.

FIG. 3A shows a state in which the main magnetic pole layer 20 and the barrier layer 22 are viewed from the end surface direction.
In this embodiment, after the main magnetic pole layer 20 is covered with the barrier layer 22, the main magnetic pole is formed by using the FIB method. FIG. 3B shows a state in which the barrier layer 22 and the main magnetic pole layer 20 are irradiated with a focused ion beam to open the barrier layer 22 and the main magnetic pole layer 20, and one side surface of the main magnetic pole 10 is formed. c) shows a state in which the other side surface of the main magnetic pole 10 is formed by the FIB method.
FIG. 5 is a plan view of the opening 30 formed in the barrier layer 22 and the main magnetic pole layer 20 using a focused ion beam. The barrier layer 22 and the main magnetic pole layer 20 are deposited on the entire surface of the workpiece, and the openings 30 are provided so as to open in a square shape on both sides of the main magnetic pole 10. In this embodiment, the opening 30 is formed to have a size of about 1.0 μm in length and width.

  Since the side surface of the main magnetic pole 10 is formed into a tapered surface having an inclination angle of 80 ° to 85 °, the focused ion beam is 10 ° to 20 ° with respect to the direction perpendicular to the plane of the barrier layer 22 and the main magnetic pole layer 20. Irradiate at an angle. Actually, since the focused ion beam is finely focused, the focused ion beam is scanned so as to form a rectangular opening 30. The FIB implementation conditions used in this embodiment are an acceleration voltage of 30 kV, a beam current of 2.2 μA, an apparatus irradiation angle of 15 °, and a beam diameter of 45 nm.

As described above, the method of forming the main magnetic pole 10 by irradiating the focused ion beam enables the taper angle of the side surface of the main magnetic pole 10 to be accurately set, and by adjusting the irradiation angle of the focused ion beam. There is an advantage that the taper angle of the side surface of the main magnetic pole 10 can be set to an arbitrary angle. According to this method, the taper angle of the side surface of the main magnetic pole 10 can be formed with a variation of 80 ° ± 1 °. This is much higher accuracy than the variation in the conventional method using the ion milling method described above is about 80 ° ± 10 °.
Further, by setting the irradiation position of the focused ion beam, the core width of the main magnetic pole 10 can be accurately defined. The variation of the core width of the main magnetic pole 10 by this method is 0.1 μm ± 0.02 (3σ), and the variation of the core width is 1/5 compared to the conventional method by the ion milling method.
As described above, the method of forming the main magnetic pole 10 using the FIB method of the present embodiment has an advantage that the main magnetic pole 10 can be formed with higher accuracy than the conventional method.
In the case of the present embodiment, when the opening 30 is formed by the FIB method, the ion beam is irradiated while the barrier layer 22 and the main magnetic pole layer 20 are applied to the entire surface of the workpiece. The surface can be prevented from being charged, and in this respect also, there is an advantage that accurate FIB processing can be performed.

After the side surface shape of the main magnetic pole 10 is formed, the main magnetic pole 10 is patterned into a predetermined planar shape. As a pre-process for patterning the main magnetic pole 10, first, the surface of the barrier layer 22 is covered with a protective layer 32 as shown in FIG. 2A in order to protect the main magnetic pole 10. The protective layer 32 is formed by sputtering an insulating material such as alumina or silica, and covers the surface of the barrier layer 22 and fills the opening 30 with an insulating material to protect the side surface of the main pole 10. It is.
FIG. 4A shows a state in which the surface of the barrier layer 22 is covered with the protective layer 32 and the opening 30 is filled with alumina. The thickness of the protective layer 32 is about 300 nm ± 50 nm. If the thickness of the protective layer 32 is thin, the durability cannot be ensured, and if it is too thick, the processing time in the ion milling process in the subsequent process becomes long.

After forming the protective layer 32, as shown in FIG. 2B, a protective resist layer 34 for patterning the main magnetic pole 10 is formed. The protective resist layer 34 is provided so as to cover the surface of the protective layer 32, and then exposed and developed to form a resist pattern 34a according to the planar pattern of the main pole 10. FIG. 4B shows a state in which the resist pattern 34 a is formed by patterning the protective resist layer 34. As shown in FIG. 4B, in the narrow portion of the main magnetic pole 10, the side surface of the resist pattern 34 a is formed with a width that shields the main magnetic pole 10 inside the opening 30.
FIG. 5B shows a planar arrangement of the narrow portion 25, the opening 30 and the resist pattern 34a of the main magnetic pole 10. In the narrow portion 25 of the main magnetic pole 10, the resist pattern 34 a is patterned so as to pass through the inside of the opening 30.

  FIG. 4C shows a state where unnecessary portions of the barrier layer 22 and the main magnetic pole layer 20 are etched by ion milling using the resist pattern 34a as a mask. In this ion milling process, the part to be the main magnetic pole 10 is covered and protected by the resist pattern 34a, and the part not covered by the resist pattern 34a is removed by ion milling. In the ion milling process, ion milling is performed perpendicularly to the surface of the workpiece in the first step, and scattered matter scattered on the side surfaces of the main magnetic pole 10 is removed by ion milling from an oblique direction in the second step.

FIG. 4 (d) shows a state in which the main magnetic pole 10 is formed by removing the resist pattern 34a that has been altered by ion milling. The resist pattern 34a altered by the ion milling process can be removed by plasma treatment, chemical treatment, or the like.
In this way, the main magnetic pole 10 in which the cross-sectional shape of the tip portion is formed in an inverted trapezoidal shape can be obtained. FIG. 2C shows a cross-sectional configuration of the write magnetic pole in a state in which the main magnetic pole 10 is formed as seen from the side surface direction. A barrier layer 22 is formed on the upper surface of the main magnetic pole 10, and a protective layer 32 is deposited on the surface of the barrier layer 22. In this embodiment, unnecessary portions of the barrier layer 22 and the main magnetic pole layer 20 are removed by ion milling. However, they can be removed by reactive ion etching without using ion milling.

  In the manufacturing method of the perpendicular magnetic recording head of the present embodiment, the tip portion of the main magnetic pole 10 is formed using the FIB method. Therefore, even when the main magnetic pole layer 20 is made of a single material such as FeCo, Even in the case of a multilayer film, the side surface of the main magnetic pole 10 can be formed in a predetermined tapered surface without being stepped. Further, as described above, when the FIB method is used, the main magnetic pole layer 10 can be formed in a predetermined shape simply by aiming at the barrier layer 22 and the main magnetic pole layer 20 and irradiating the focused ion beam. There is no need to form a mask on the surface of the layer 22. Further, by irradiating the focused ion beam with the main magnetic pole layer 20 covered with the barrier layer 22, the edge portion of the main magnetic pole 10 can be formed at an acute angle, and the writing accuracy of the magnetic head can be improved.

It is side surface sectional drawing which shows the manufacturing process of the perpendicular magnetic recording head based on this invention. It is side surface sectional drawing which shows the manufacturing process of the perpendicular magnetic recording head based on this invention. FIG. 6 is a front sectional view showing a manufacturing process of the perpendicular magnetic recording head according to the present invention. FIG. 6 is a front sectional view showing a manufacturing process of the perpendicular magnetic recording head according to the present invention. It is explanatory drawing which shows the planar arrangement | positioning of an opening part and a resist pattern. It is explanatory drawing which shows the end surface shape of the main pole of a perpendicular magnetic recording head. It is side surface sectional drawing which shows the manufacturing process of the conventional perpendicular magnetic recording head. It is front sectional drawing which shows the manufacturing process of the conventional perpendicular magnetic recording head. It is explanatory drawing which shows the planar shape of a main pole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main pole 12 Return yoke 13 Insulating layer 14 Coil 16 Back closure 17 Insulating layer 18 Main pole thickening layer 20 Main pole layer 22 Barrier layer 24 Resist layer 24a Resist pattern 25 Narrow width part 30 Opening part 32 Protective layer 34 Protective resist layer 34a resist pattern

Claims (5)

In a method of manufacturing a perpendicular magnetic recording head comprising a magnetic yoke having a main magnetic pole facing a recording medium, a write magnetic pole having a coil wound around the magnetic yoke, and a reproducing element,
Forming a main magnetic pole layer to be the main magnetic pole;
Forming a barrier layer made of a nonmagnetic material on the surface of the main magnetic pole layer;
Irradiating the barrier layer and the main magnetic pole layer with a focused ion beam to form a tip portion of the main magnetic pole having a reverse trapezoidal cross section.   When the barrier layer and the main magnetic pole layer are irradiated with a focused ion beam to form the tip of the main magnetic pole having a cross-sectional shape of an inverted trapezoid, the barrier layer and the main magnetic pole layer are etched so as to sandwich the main magnetic pole. 2. A method of manufacturing a perpendicular magnetic recording head according to claim 1, further comprising the step of forming an opening.   When the focused ion beam is irradiated to the barrier layer and the main magnetic pole layer to form the tip portion of the main magnetic pole having a cross-sectional shape of an inverted trapezoid, the focused ion beam is irradiated and scanned at an incident angle of 10 ° to 20 °. 2. The method of manufacturing a perpendicular magnetic recording head according to claim 1, further comprising the step of: After forming the tip of the main pole, forming a protective resist layer on the surface of the barrier layer, patterning the protective resist layer to form a resist pattern that covers the main pole;
2. The method of manufacturing a perpendicular magnetic recording head according to claim 1, further comprising a step of removing a portion of the barrier layer excluding the main pole and the main pole layer using the resist pattern as a mask. Providing a protective layer covering the opening and the barrier layer after forming the tip of the main pole; and
Forming a protective resist layer on the surface of the protective layer, patterning the protective resist layer to form a resist pattern covering the main pole;
3. A method of manufacturing a perpendicular magnetic recording head according to claim 2, further comprising a step of removing a portion of the barrier layer excluding the main magnetic pole and the main magnetic pole layer using the resist pattern as a mask.

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