METHOD FOR MANUFACTURING MAGNETIC HEAD
According to an aspect of an embodiment, a method for manufacturing a magnetic head includes: providing a substrate; forming a first magnetic layer having a pattern for forming a magnetic pole on the substrate; forming a stopper layer of non-magnetic material on the top and the sides of the first magnetic layer; reducing the thickness of the stopper layer on the top of the first magnetic layer; and forming a second magnetic layer on the stopper layer. The method further includes: polishing the second magnetic layer to expose the stopper layer on the top of the first magnetic layer; and removing the stopper layer on the top of the first magnetic layer, so as to expose the top of the first magnetic layer.
Latest FUJITSU LIMITED Patents:
- METHOD AND APPARATUS FOR EVALUATING TRANSMISSION IMPAIRMENTS OF MULTIPLEXING CONVERTER
- COMPUTER-READABLE RECORDING MEDIUM STORING DETECTION PROGRAM, DETECTION METHOD, AND DETECTION APPARATUS
- FORWARD RAMAN AMPLIFIER, BIDIRECTIONAL RAMAN AMPLIFICATION SYSTEM, AND FORWARD RAMAN AMPLIFICATION SYSTEM
- TRAINING METHOD, ARITHMETIC PROCESSING DEVICE, AND COMPUTER-READABLE RECORDING MEDIUM STORING TRAINING PROGRAM
- COMPUTER-READABLE RECORDING MEDIUM STORING SAMPLING PROGRAM, SAMPLING METHOD, AND INFORMATION PROCESSING DEVICE
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-322674 filed on Dec. 14, 2007, the entire content of which is incorporated herein by reference.
BACKGROUND1. Field
This art relates to magnetic heads for writing information on recording media.
2. Description of the Related Art
In magnetic heads used in magnetic disk devices, the skew angle is varied depending on whether the arm supporting the magnetic head lies at the inner periphery side or at the outer periphery side of the recording medium.
This causes the so-called side track erase problem that information written in the adjacent track is erased, or that the SN ratio of the magnetic recording is reduced. In order to prevent the side track erase problem, the recording magnetic pole has an inverted trapezoidal end face.
As the recording density of recording media is increased, however, the side erase problem becomes noticeably occurring. Accordingly, techniques have been proposed in which side shields are disposed with the magnetic pole in between to prevent the magnetic flux from leaking to the adjacent tracks (Japanese Laid-open Patent Publications No. 2007-52904, No. 2007-35082, and No. 2007-257742).
SUMMARYAccording to an aspect of an embodiment, a method for manufacturing a magnetic head includes: providing a substrate; forming a first magnetic layer having a pattern for forming a magnetic pole on the substrate; forming a stopper layer of non-magnetic material on the top and the sides of the first magnetic layer; reducing the thickness of the stopper layer on the top of the first magnetic layer; forming a second magnetic layer on the stopper layer; polishing the second magnetic layer to expose the stopper layer on the top of the first magnetic layer; and removing the stopper layer on the top of the first magnetic layer, so as to expose the top of the first magnetic layer.
In order to form the main magnetic pole 10 of a recording head, for example, a substrate is coated with a resist layer, and the resist layer is patterned so as to form an opening corresponding to the shape of the main magnetic pole. A magnetic material is deposited to raise the level in the opening by plating. Thus, a main magnetic pole is formed. Since the upper surface of the deposition of the magnetic material in the opening is curved, the upper surface is polished to planarize so that the narrow end portion of the magnetic pole can be formed in an inverted trapezoidal shape.
The recording accuracy is significantly affected by the shape of the end face of the main magnetic pole. It is therefore desirable that the main magnetic pole be formed with a proper height (thickness) and core width. An extremely large number of magnetic heads are formed in a substrate. For forming main magnetic poles having a desired shape in the substrate by polishing, the manufacturing process must be carefully performed so that highly precise working can be achieved.
When the side shields are formed in addition to the main magnetic pole, the side shields must be reliably formed without degrading the accuracy in the formation of the main magnetic pole.
Preferred embodiments will now be described in detail with reference to the drawings.
First EmbodimentThen, a resist pattern 22 is formed on the surface of the plating seed layer 21 (
Since the narrow end of the main magnetic pole is formed in an inverted trapezoidal shape, the region in the opening 22a in which the narrow end of the main magnetic pole will be formed is formed in an inverted trapezoidal shape in sectional view. After exposure and development of the resist layer, the open side of the opening 22a is expanded to have a larger width than the bottom side through a heating step. Thus, the opening 22a has an inverted trapezoidal section, having an inclined inner wall.
Then, a first magnetic layer 23 is deposited to raise the level in the opening 22a of the resist pattern 22 by electroplating using the plating seed layer 21 as a plating power supply layer (
Then, the resist pattern 22 is removed to form the first magnetic layer 23 intended for the main magnetic pole on the surface of the plating seed layer 21 (
Preferably, the material of the stopper layer 24 is a non-magnetic material that can favorably act as a polishing stopper, such as Ta (tantalum).
The thickness of the stopper material coating the side surfaces of the first magnetic layer 23 near the narrow end defines the interval D of the side gap. The side gap can be therefore controlled by adjusting the sputtering conditions.
In the step of reducing the thickness of the stopper layer 24, the surface of the stopper layer 24 directly exposed to the milling ions at portions adjacent to the first magnetic layer 23 is etched simultaneously, the thickness of the stopper layer 24 directly exposed to the milling ions at portions adjacent to the first magnetic layer 23 being reduced. The etching of the surface causes the first magnetic layer 23 to be covered with the side shields widely. In a magnetic disk device having the magnetic head according to the embodiment and a magnetic disk, the side shields effectively prevent the magnetic flux from leaking to the adjacent tracks adjacent to the track where magnetic information is to be written during writing operations. Consequently it is highly unlikely that the side track erase is caused. The larger the interval D of the side gap is, the more effectively the step of reducing the thickness of the stopper layer 24 contributes to preventing the side track erase.
Then, a plating base 25 is formed over the entire surface of the substrate by sputtering (
Then, the surface of the substrate coated with the plating base 25 is further coated with a resist layer. The resist layer is exposed to light and developed to form a resist pattern 26 having an opening (a groove) 26a at the sides of the narrow end of the first magnetic layer 23 (
The side shields are formed in practice so as to extend to the positions quite distant (about 1 to 25 μm) from the sides of the main magnetic pole. Although
Then, a second magnetic layer 27 is deposited to raise the level in the opening 26a by electroplating using the plating base 25 as a plating power supply layer (
The second magnetic layer 27 is intended for the side shields. A soft magnetic material having superior shielding properties, such as NiFe, can be used for the second magnetic layer 27. The stopper layer 24 is formed of a material that can be polished at a lower rate (more difficult to polish) than the magnetic material of the second magnetic layer 27. In other words, the second magnetic layer 27 is formed of a magnetic material that can be polished at a higher rate than the stopper layer 24.
Polishing the Second Magnetic LayerIn the step shown in
Subsequently, the surface of the substrate is subjected to a first polishing step. In the first polishing step, the insulating layer 28 and the second magnetic layer 27 are polished to planarize the surface of the substrate. The first polishing step can be performed by CMP (Chemical Mechanical Polishing).
In
Then, the surface of the substrate is subjected to ion milling through the resist pattern 30 as a mask to remove the portion of the non-magnetic layer 29 exposed at the surface of the substrate.
Then, the trailing shield is formed by electroplating, as shown in
In
A return yoke is formed on the trailing shield 34. After the step shown in
Thus, a read head is completed which includes the side shields 27a disposed with the inverted trapezoidal narrow end of the magnetic pole 23a in between, and the trailing shield 34 over the main magnetic pole 23a with a predetermined distance.
In the magnetic head produced in practice, the side shields 27a extend to positions quite distant from the main magnetic pole 23a, unlike the structure shown in
In this method, the first magnetic layer 23 is formed into a desired shape of the main magnetic pole by ion milling. In addition, this method allows the underlying layer of the first magnetic layer 23 to be etched to the level lower than the bottom of the first magnetic layer 23.
By etching the plating seed layer 21 or further etching the base layer 20 at the sides of the first magnetic layer 23 to the level lower than the bottom of the first magnetic layer 23, the side shields 27a, which are formed in a subsequent step, can shield the entire main magnetic pole 23a in the height direction (thickness direction).
Since the plating seed layer 21 and the base layer 20 are etched to a level lower than the bottom of the first magnetic layer 23, the bottoms of the side shields 27a lie below the bottom of the main magnetic pole 23a and the sides of the main magnetic pole 23a are covered with the side shields 27a. The positional relationship between the side shields 27a and the main magnetic pole 23a is clearly different from that shown in
By shielding the sides of the main magnetic pole 23a including the portion around the bottom by the side shields 27a, as described above, the recording magnetic pole can be shielded on the sides effectively.
Second EmbodimentIn the first embodiment, a side gap layer is formed by sputtering a single stopper material after forming the first magnetic layer 23, as shown in
Then, the surface of the substrate is subjected to ion milling to remove the first insulating layer 24b coating the top of the first magnetic layer 23 until the stopper layer 24a is exposed (
Then, a plating base 25 is formed over the entire surface of the substrate by sputtering.
After forming the plating base 25, the same steps as in the first embodiment are performed.
In the present embodiment as well, the surface of the substrate is planarized by the first polishing step to a height at which the surface of the stopper layer 24a is exposed. The top of the stopper layer 24a is selectively removed by RIE, and thus, the main magnetic pole 23a and the side shields 27a are formed.
The following steps are performed in completely the same manner as the steps shown in
In the read head of the present modification, the bottoms of the side shields 27a lie below the bottom of the main magnetic pole 23a and the side surfaces of the main magnetic pole 23a are covered with the side shields 27a entirely in the height direction. Consequently, the magnetic pole can be shielded effectively by the side shields 27a.
In the magnetic head manufacturing method according to the present embodiment, a recording magnetic pole having side shields can be precisely formed in a desired shape with the distances between the side shields and the magnetic pole controlled. In particular, even in a process manufacturing an extremely large number of magnetic heads on a wafer, the end face of the main magnetic pole of each magnetic head can be precisely formed by, for example, polishing a structure in which the top of the first magnetic layer is coated with a stopper layer.
Since in the method according to the embodiments, the side gaps and the gap between the main magnetic pole and the trailing shield are formed in different steps, each gap can be formed precisely.
Since the method according to the embodiments has the step of reducing the thickness of the stopper layer, the first magnetic layer is covered with the side shields widely. In a magnetic disk device having the magnetic head according to the embodiment and a magnetic disk, the side shields effectively prevent the magnetic flux from leaking to adjacent tracks adjacent to the track where magnetic information is to be written during writing operations. Consequently it is highly unlikely that the side track erase is caused.
While the above described embodiments illustrate methods for manufacturing a perpendicular magnetic head including a main magnetic pole, an another embodiment may be applied to methods for manufacturing longitudinal magnetic heads.
Claims
1. A method for manufacturing a magnetic head comprising:
- providing a substrate;
- forming a first magnetic layer having a pattern for forming a magnetic pole on the substrate;
- forming a stopper layer of non-magnetic material on the top and the sides of the first magnetic layer;
- reducing the thickness of the stopper layer on the top of the first magnetic layer;
- forming a second magnetic layer on the stopper layer;
- polishing the second magnetic layer to expose the stopper layer on the top of the first magnetic layer; and
- removing the stopper layer on the top of the first magnetic layer, so as to expose the top of the first magnetic layer.
2. The method according to claim 1, wherein the stopper is formed of tantalum.
3. The method according to claim 1, wherein forming the first magnetic layer includes:
- forming a plating seed layer on the substrate;
- forming a resist pattern on the plating seed layer, the resist pattern having an opening in which the plating seed layer is exposed at the bottom; and
- electroplating by using the plating seed layer as a plating power supply layer so as to form the first magnetic layer on a part of the plating seed layer in the opening.
4. The method according to claim 1, further comprising:
- etching the upper side of the substrate by using the first magnetic layer as a mask.
5. The method according to claim 3, further comprising:
- etching the plating seed layer by using the first magnetic layer as a mask after forming the first magnetic layer.
6. The method according to claim 5, further comprising:
- etching the upper side of the substrate by using the first magnetic layer as a mask.
7. The method according to claim 1, further comprising:
- polishing the surface of the substrate to finish the surface after removing the stopper layer.
8. The method according to claim 1, further comprising:
- forming on the stopper layer a resist pattern having an opening exposing a part of the stopper layer where the first magnetic layer is disposed, wherein the second magnetic layer is formed on the part of the stopper layer in the opening; and
- removing the resist pattern after forming the second magnetic layer.
9. The method according to claim 1, further comprising:
- forming an insulating layer on the second magnetic layer, wherein by polishing the second magnetic layer, the insulating layer is polished simultaneously with the second magnetic layer to form a common plane.
10. A method for manufacturing a magnetic head comprising:
- providing a substrate;
- forming a first magnetic layer having a pattern for forming a magnetic pole on the substrate on the substrate;
- forming a stopper layer of non-magnetic material on the top of the first magnetic layer;
- forming a first insulating layer on the top of the stopper layer and the sides of the first magnetic layer, the first insulating layer capable of being polished at a higher rate than the stopper layer;
- reducing the thickness of the first insulating layer on the top of the stopper layer formed on the top of the first magnetic layer;
- forming a second magnetic layer on the stopper layer;
- polishing the second magnetic layer to expose the stopper layer on the top of the first magnetic layer; and
- removing the stopper layer on the top of the first magnetic layer, so as to expose the top of the first magnetic layer.
11. The method according to claim 10, wherein the first insulating layer is formed of alumina.
12. The method according to claim 10, wherein the stopper is formed of tantalum.
13. The method according to claim 10, wherein forming the first magnetic layer includes:
- forming a plating seed layer on the substrate;
- forming a resist pattern on the plating seed layer, the resist pattern having an opening in which a part of the plating seed layer is exposed; and
- electroplating by using the plating seed layer as a plating power supply layer so as to form the first magnetic layer on a part of the plating seed layer in the opening.
14. The method according to claim 10, wherein the stopper layer of non-magnetic material is further formed on the side of the first magnetic layer.
15. The method according to claim 10, further comprising:
- etching the upper side of the substrate by using the first magnetic layer as a mask.
16. The method according to claim 13, further comprising:
- etching the plating seed layer by using the first magnetic layer as a mask after forming the first magnetic layer.
17. The method according to claim 16, further comprising:
- etching the upper side of the substrate by using the first magnetic layer as a mask.
18. The method according to claim 10, further comprising:
- polishing the surface of the substrate to finish the surface after removing the stopper layer.
19. The method according to claim 10, further comprising:
- forming on the stopper layer a resist pattern having an opening exposing a part of the stopper layer where the first magnetic layer is disposed, wherein the second magnetic layer is formed on the part of the stopper layer in the opening; and
- removing the resist pattern after forming the second magnetic layer.
20. The method according to claim 10, further comprising:
- forming a second insulating layer wherein by polishing the second magnetic layer, the second insulating layer is polished simultaneously with the second magnetic layer to form a common plane.
Type: Application
Filed: Dec 9, 2008
Publication Date: Jun 18, 2009
Applicant: FUJITSU LIMITED (Kawasaki-shi)
Inventors: Masanori Tachibana (Kawasaki), Masaya Kato (Kawasaki), Takashi Ito (Kawasaki), Hiroyuki Miyazawa (Kawasaki)
Application Number: 12/331,079
International Classification: C25D 5/02 (20060101); C25D 5/52 (20060101);