WO2001027915A1

WO2001027915A1 - Thin film magnetic head and magnetic recording medium drive device

Info

Publication number: WO2001027915A1
Application number: PCT/JP1999/005521
Authority: WO
Inventors: Ikuya Tagawa; Tomoko Kutsuzawa; Syuji Nishida; Teruo Kiyomiya; Yoshinori Ohtsuka; Hiroshi Maeda; Minoru Hasegawa; Masahiro Kakehi; Takashi Sekikawa; Yukinori Ikegawa
Original assignee: Fujitsu Limited
Priority date: 1999-10-07
Filing date: 1999-10-07
Publication date: 2001-04-19

Abstract

A thin film magnetic head provided with an upper sub-magnetic pole (40) facing a medium opposing surface at the front end thereof and extending in a longitudinal direction and with a specified thickness along a reference surface (41). An intermediate magnetic pole layer which extends along the reference surface and is defined to be larger in a track width direction than the upper sub-magnetic pole is connected to the rear end of the upper sub-magnetic pole. An upper magnetic pole layer (33) supported on the front surface of the intermediate magnetic pole layer projects at the tip end thereof facing the medium opposing surface from the pole (40) by a specified distance ΔPW in the track width direction. For example, when the core width CW of the pole (40) is set to at least 0.7 νm, the thickness SL of the pole (40) is set to at least 2.5 times the projecting distance ΔPW of the upper magnetic pole layer (33). Setting the thickness SL of pole (40) ensures a sufficient magnetic field intensity (e.g., at least 470 kA/m) for an information record between the pole (40) and a lower sub-magnetic pole (38), whereas, a magnetic field intensity at the edge of the upper magnetic pole layer (33) projecting in the track width direction is suppressed to below a threshold value (e.g., 135 kA/m) at which recording bleeding and magnetization inversion may be encountered.

Description

Description Thin film magnetic head and magnetic recording medium drive

The present invention relates to a thin-film magnetic head employed in a magnetic recording medium drive such as a magnetic disk drive and a magnetic tape drive, and more particularly, to an upper sub-pole which faces a medium facing surface at a front end and extends in a front-rear direction along a reference surface The intermediate pole layer, which extends along the reference plane from the rear end of the upper sub-pole and is larger in the track width direction than the upper sub-pole, is received by the surface of the intermediate pole layer and faces the medium facing surface. The present invention relates to a thin-film magnetic head having an upper magnetic pole layer projecting in the track width direction from an upper sub magnetic pole at a tip. Background art

A thin-film magnetic head including a narrow upper sub-pole and a lower sub-pole facing each other with a gap layer therebetween at a medium facing surface is widely known. In such a thin-film magnetic head, in addition to the narrow gap magnetic field (recording magnetic field) formed by the narrow upper sub-pole and the lower sub-pole, the upper pole protruding from the upper sub-pole in the track width direction on the medium facing surface. An extra stray field is created at the edge of the layer. Such a leakage magnetic field affects a recording track adjacent to a target recording track during writing. For example, when the leakage magnetic field increases, magnetization reversal occurs in a recording track adjacent to the target recording track. Unless such magnetization reversal is prevented, the recording density of the recording medium cannot be increased as expected.

In realizing the reduction of the leakage magnetic field, for example, in the thin-film magnetic head described in JP-A-11-167705, it is specified to be larger in the track width direction than the upper sub-pole. An intermediate pole layer is connected to the rear end of the upper sub-pole. According to such an intermediate magnetic pole layer, a larger joint surface can be secured between the intermediate magnetic pole layer and the upper magnetic pole layer as compared with the narrow upper sub magnetic pole. Magnetic saturation occurring at the junction surface is reduced. When the magnetic saturation force S is relaxed in this way, the extra leakage magnetic field generated at the edge of the upper pole layer is reduced. At present, the upper magnetic pole layer is often formed by an electrolytic plating method. However, since the coil pattern is formed on a molding surface including a partly inclined surface after the coil pattern is formed, it is considered difficult to further narrow the upper pole layer from about 1.2 m along the track width direction. Can be On the other hand, it is expected that the upper sub pole will be further narrowed in the future. As a result, the overhang of the upper pole layer increases. When the amount of overhang increases, the above-mentioned leakage magnetic field is expected to increase. Disclosure of the invention

The present invention has been made in view of the above situation, and has been developed to provide a thin-film magnet that can suppress an extra leakage magnetic field generated at the edge of the upper magnetic pole layer to a specified value or less even if the amount of overhang of the upper magnetic pole layer increases. The purpose is to provide a code.

In order to achieve the above object, according to the first invention, an upper sub-magnetic pole facing the medium facing surface at the front end and extending in the front-rear direction with a predetermined thickness along the reference plane, and a rear end of the upper sub-magnetic pole from the rear end An intermediate pole layer that extends along the reference plane and is defined in the track width direction larger than the upper sub-pole, and is received by the surface of the intermediate pole layer and has a track width from the upper sub-pole at the tip facing the medium facing surface. And a top pole layer extending in a direction by a predetermined amount. At this time, the thickness of the upper sub pole is set to be at least 2.5 times the overhang of the upper pole layer.

According to the present inventors, it has been newly found that an extra leakage magnetic field, that is, an edge magnetic field generated at the edge of the upper magnetic pole layer projecting from the track width direction of the upper sub magnetic pole depends on the thickness of the upper sub magnetic pole. . For example, if the core width of the upper sub-pole measured in the track width direction is set to 0.7 m or more, the thickness of the upper sub-pole is set to 2.5 times or more the overhang of the upper pole layer. Is desirable. When the thickness of the upper sub-pole is set in this manner, a magnetic field strength (for example, about 470 kAZm or more) sufficient for information recording between the upper sub-pole and the lower pole layer (including the lower sub-pole) is secured. However, it is possible to suppress the edge magnetic field below a threshold (for example, about 135 kAZm) that causes recording blurring and magnetization reversal. Therefore, when recording information on the magnetic recording medium, it is possible to eliminate the problems such as the recording bleeding of the recording track and the magnetization reversal of the recording track adjacent to the target recording track. Narrow recording tiger The lock can be realized.

Further, when the core width of the upper sub-pole is set to 0.5 or more, it is desirable that the thickness of the upper sub-pole is set to 3.17 times or more the overhang amount of the upper pole layer. When the thickness of the upper sub-pole is set in this manner, a magnetic field intensity sufficient for information recording (for example, about 470 kAZm) between the upper sub-pole and the lower pole layer (including the lower sub-pole) is set as described above. It is possible to keep the edge magnetic field below the threshold (for example, about 135 kA / m) that causes recording bleeding and magnetization reversal while maintaining the above. Further, according to the second invention, the upper sub-pole which faces the medium facing surface at the front end and extends in the front-rear direction at a predetermined thickness along the reference plane, and extends from the rear end of the upper sub-pole along the reference plane. A middle pole layer defined to be larger in the track width direction than the upper sub pole, and an upper pole layer facing the medium facing surface at the front end and received on the surface of the middle pole layer. A head is provided. At this time, the saturation flux density of the upper sub pole is set to 1.4 T or more.

According to the present inventors, it has been newly found that an extra leakage magnetic field, i.e., an edge magnetic field generated by an edge of an upper magnetic pole layer projecting from a track width direction of an upper auxiliary magnetic pole depends on a magnetic flux saturation density of the upper auxiliary magnetic pole. Was. For example, when the saturation magnetic flux density B s of the upper sub-pole is set to 1.4 T or more, a magnetic field strength sufficient for information recording between the upper sub-pole and the lower pole layer (including the lower sub-pole) (for example, about 4 It is possible to keep the edge magnetic field below a threshold value (for example, about 135 kA / m) that causes recording bleeding and magnetization reversal, while maintaining 70 kAZm or more. Therefore, in recording information on the magnetic recording medium, it is possible to solve the problems such as blurring of recording of a recording track and magnetization reversal of a recording track adjacent to a target recording track. In order to realize such a saturation magnetic flux density B s, the upper auxiliary magnetic pole is, for example, 5 ON i 50 F e (B s = 1.4 T) or 45 N i 55 F e (B s = 1 6 T).

In the thin-film magnetic head according to the first and second aspects of the present invention, it is desirable that the intermediate pole layer is defined to be larger in the track width direction than the upper pole layer. According to such an intermediate magnetic pole layer, a larger joint surface can be secured between the intermediate magnetic pole layer and the upper magnetic pole layer as compared with the narrow upper sub magnetic pole. The magnetic saturation that occurs at the junction is relaxed, resulting in the upper secondary pole The extra leakage magnetic field generated at the edge of the upper magnetic pole layer projecting in the track width direction is reduced.

The upper magnetic pole layer includes a front end piece facing the air bearing surface at the front end and extending in the front-rear direction, and a main body connected to the rear end of the front end piece and gradually spreading in the track width direction as the distance from the front end piece increases. Is also good. At this time, it is desirable that the tip of the main body is received on the surface of the intermediate magnetic pole layer. As a result, magnetic saturation can be reliably reduced between the tip of the tapered main body and the intermediate magnetic pole layer.

The thin-film magnetic head as described above can be employed in a magnetic recording medium drive such as a hard disk drive (HDD), a magnetic disk drive, or a magnetic tape drive. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view schematically showing the internal structure of a hard disk drive (HDD).

FIG. 2 is an enlarged perspective view showing a specific example of the flying head slider.

FIG. 3 is a plan view schematically showing the structure of the inductive write head element (thin film magnetic head).

FIG. 4 is a partial cross-sectional view taken along line 414 of FIG.

FIG. 5 is a front view showing the state of the air bearing surface observed from the direction of arrow 5 in FIG. FIG. 6 is an enlarged plan view of the inductive write head element viewed from the direction of arrow 6 in FIG.

7A and 7B are graphs showing the relationship between the overhang amount 張り PW of the upper pole layer and the magnetic field strength of the recording magnetic field and the edge magnetic field.

FIG. 8 is a graph showing the relationship between the core width CW and the magnetic field strength of the recording magnetic field and the edge magnetic field.

FIG. 9 is a graph showing the relationship between the thickness S L of the upper sub-magnetic pole derived when the core width CW = 0.7 / x m and the magnetic field strength of the recording magnetic field and the edge magnetic field.

FIG. 10 is a graph showing the relationship between the thickness S of the upper sub-magnetic pole derived when the core width CW = 0.5 / m and the magnetic field strength of the recording magnetic field and the edge magnetic field. FIG. 11 is a graph showing the relationship between the saturation magnetic flux density B s of the upper sub pole and the magnetic field strength of the recording magnetic field and the edge magnetic field.

FIG. 12 is a partially enlarged plan view of the wafer 1 showing voids defined by the photoresist film.

FIGS. 13A to 13C are diagrams schematically showing a process of manufacturing an inductive write head element until an upper auxiliary magnetic pole is formed.

FIG. 14 is an enlarged plan view schematically showing the slimming-processed upper magnetic pole layer. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an internal structure of a hard disk drive (HDD) 10 as a specific example of a magnetic recording medium drive. The housing 11 of the HDD 10 accommodates, for example, a magnetic disk 13 mounted on a spindle 12 of a spindle motor and a flying head slider 14 facing the magnetic disk 13. The flying head slider 14 is fixed to the tip of a carriage arm 16 that can swing around a swing axis 15. When writing and reading information to and from the magnetic disk 13, the carriage arm 16 is oscillated by the actuator 17, which is composed of a magnetic circuit. As a result, the flying head slider 14 is placed on the magnetic disk 13. Is positioned on the desired recording track. The internal space of the housing 11 is closed by a cover (not shown).

FIG. 2 shows a specific example of the flying head slider 14. The flying head slider 14 is joined to a slider body 21 made of Al ₂ 〇 ₃ — TiC (Altic) and an air outflow end of the slider body 21, and a read / write head 2 2 and a a 1 ₂ 0 ₃ (alumina) manufactured head protection layer 2 3 having a built-in. In the slider body 21 and the head element built-in film 23, a medium facing surface, that is, a flying surface 24 facing the magnetic disk 13 spreads. On the floating surface 24, two rails 25 are formed on the top surface to define ABS (air bearing surface). The flying head slider 14 utilizes the airflow 26 received on the flying surface 24 (especially ABS) during the rotation of the magnetic disk 13. It can fly from the surface of the magnetic disk 13.

The structure of the read / write head 22 will be described in detail with reference to FIG. The read / write head 22 includes an inductive write head element 29 for recording information on the magnetic disk 13 using a magnetic field generated by the spiral conductive coil pattern 28. This inductive write head element 29 functions as the thin-film magnetic head according to the present invention. When a magnetic field is generated in the conductive coil pattern 28, the lines of magnetic force propagate in the magnetic core 30 that passes through the center of the conductive coil pattern 28.

The magnetic core 30 includes a lower magnetic pole layer 31 facing the air bearing surface 24 at the tip. The lower magnetic pole layer 31 extends from the air bearing surface 24 at, for example, a depth of 25 m. As shown in FIG. 4, a magnetic piece 32 penetrating through the center of the conductive coil pattern 28 and communicating with the lower magnetic pole layer 31 is connected to the lower magnetic pole layer 31. The distance from the air bearing surface 24 to the magnetic piece 32 is set to, for example, about 15 m. The upper magnetic pole layer 33 sandwiching the conductive coil pattern 28 between the lower magnetic pole layer 31 and the lower magnetic pole layer 31 extends from the upper end of the magnetic piece 32 toward the floating surface 24, and the front end faces the floating surface 24. The upper pole layer 33 and the lower pole layer 31 may be made of, for example, NiFe. The film thickness of the upper magnetic pole layer 33 and the lower magnetic pole layer 31 is set to, for example, about 3.0 m.

Such an inductive write head element 29 is formed on an alumina layer 36 in which a magnetic resistance (MR) element 35 used for reading information is embedded. The lower magnetic pole layer 31 of the induction writing head element 29 has an alumina layer 36 sandwiched between the lower shield layer 37 of FeN and NiFe. Here, the lower magnetic pole layer 31 functions as an upper shield layer of the MR element 35. As a result, as apparent from FIG. 3, for example, at the tip of the inductive write head element 29 facing the air bearing surface 24, the lower magnetic pole layer 31 is wider than the upper magnetic pole layer 33. However, other read elements such as giant magnetoresistive (GMR) elements may be used instead of the MR element 35, and the inductive write head element 29 is used alone without using the read element. Is also good.

As is apparent from FIG. 5 as well, the lower pole layer 31 is formed with a lower auxiliary pole 38 which faces the air bearing surface 24 at the front end and extends in the front-rear direction along the surface of the lower pole layer 31. Is done. The thickness of the lower sub pole 38, that is, from the surface of the lower pole layer 3 1 Is set to, for example, about 0.3 m. The lower sub pole 38 may be formed integrally with the lower pole layer 31. The upper sub-pole 40 faces the lower sub-pole 38 with a gap layer 39 having a thickness of about 0.25 zim. Similarly, the upper sub-pole 40 faces the air bearing surface 24 at the front end and extends in the front-rear direction with a predetermined thickness SL along the reference surface 41. The lower sub-pole 38 and the upper sub-pole 40 spread with a prescribed core width CW in the track width direction. The upper pole layer 33 extends from the upper sub-pole 40 along the air bearing surface 24 in the track width direction by a predetermined extension amount APW.

In such an inductive write head element 29, the magnetic pole lines transmitted through the magnetic core 30 pass between the narrow upper sub-pole 40 and the lower sub-pole 38 while bypassing the gap layer 39. As a result, the magnetic disk 13 facing the floating surface 24 is magnetized by the narrow gap magnetic field (recording magnetic field) leaking from the floating surface 24. Therefore, the track width on the recording medium can be reduced as compared with the case where the gap layer formed by the upper magnetic pole layer 33 and the lower magnetic pole layer 31 is simply used. It is considered that the track density is increased and the areal recording density on the magnetic disk 13 is further increased. In addition, the upper magnetic pole layer 33 can protrude in the track width direction from the upper sub magnetic pole 40 along the air bearing surface 24, and good overwrite characteristics can be obtained.

As shown in FIG. 6, at the rear end of the upper sub-pole 40, the intermediate pole layer 4, which extends along the reference plane 41 and is larger in the track width direction than the upper sub-pole 40, is provided. 2 is connected. The intermediate magnetic pole layer 42 and the upper auxiliary magnetic pole 40 may be formed integrally. The tips of the upper pole layer 33 are received on the surfaces of the upper sub pole 40 and the intermediate pole layer 42. According to such an intermediate magnetic pole layer 42, a larger joint surface can be secured between the intermediate magnetic pole layer 42 and the upper magnetic pole layer 33 as compared with the narrow upper sub magnetic pole 40. The magnetic saturation generated at the junction surface is reduced, and as a result, an extra leakage magnetic field generated at the edge of the upper pole layer 33 extending from the upper sub pole 40 in the track width direction is reduced.

The middle pole layer 42 is connected to the front layer 43 that gradually widens in the track width direction as it moves away from the upper sub pole 40 toward the rear, and connected to the rear end of the front layer 43 to form the upper pole layer 3. And a rear layer which is defined to be larger in the track width direction than the rear layer. The rear layer 4 is widened, for example, with a specified width WW (= about 2.0 um) in the track width direction. You. Therefore, the rear layer 4 4 protrudes from the upper magnetic pole layer 33 in the track width direction. According to such a rear side layer 44, the maximum bonding surface can be reliably secured between the upper magnetic pole layer 33 and the upper magnetic pole layer 33. Therefore, magnetic saturation generated at the junction surface can be reliably reduced. The length of the upper sub pole 40 along the front-back direction is set to, for example, D 1 = 1.0 m, and the length of the front layer 43 and the back layer 44 along the front-back direction is, for example, D 2 = 1.0 m and D 3 = 2.0 m, respectively.

As is apparent from FIG. 6, the upper magnetic pole layer 33 has a front end piece 45 facing the air bearing surface 24 at the front end and extending forward and rearward. A main body 46 that gradually widens in the track width direction as the distance from the main body increases. The tip of the main body 46 is received on the surface of the rear layer 44 of the intermediate pole layer 42. As a result, magnetic saturation can be reliably reduced between the tip of the tapered main body 46 and the intermediate magnetic pole layer 42.

Next, the magnetic field characteristics of the inductive write head element 29 described above will be considered. In general, in the inductive write head element 29 having the narrow upper sub-pole 40, the magnetic flux of the upper sub-pole 40 is guided toward the medium surface of the magnetic disk 13 by the narrow gap layer 39. At the same time, the magnetic flux of the upper magnetic pole layer 33 leaks toward the medium surface of the magnetic disk 13 due to the edge of the upper magnetic pole layer 33 projecting from the upper auxiliary magnetic pole 40 in the track width direction. In the following description, the former is called a recording magnetic field, and the latter is called an edge magnetic field. Here, when computer simulation is performed using commercially available three-dimensional magnetic field analysis software, a simulation result as shown in FIG. 7 is obtained, for example. At this time, the coercive force of the magnetic disk 13 is set to, for example, Hc = 270 kAZm. Under these conditions, the recording magnetic field passing between the upper sub-pole 40 and the lower sub-pole 38 over the narrow gap layer 39 generally has a recording magnetic field of, for example, about 470 kAZm or more (coercive force He of 1 (About 5 times to 2 times). In addition, when a magnetic field of 135 kAZm or more (about 1 Z2 of coercive force Hc) acts on the magnetic disk 13 other than the recording magnetic field, the magnetization reversal is caused. Therefore, the aforementioned edge magnetic field must be kept below 135 kAZm.

As shown in FIGS. 7A and 7B, in general, in the inductive write head element having the upper sub-pole 40, as the overhang A PW of the upper pole layer 33 increases, Thus, the edge magnetic field increases. However, in the inductive write head element 29 according to the present invention, as is apparent from FIG. 7A, a sufficient recording magnetic field exceeding 470 kAZm is secured, and at the same time, the edge magnetic field is reduced to less than 135 kAZm. For suppressing, the overhang amount APW can be tolerated in a wide range such as 0 <ΔPW≤4.5 m. When a large overhang APW is secured in this way, the upper pole layer 33, which is relatively wider than the upper sub-pole 40, may be realized, and the desired magnetic pole layer can be formed relatively easily without being restricted by manufacturing. It is possible to realize the overhang amount A PW. It is considered that such an increase in the allowable range is caused by relaxation of magnetic saturation caused by the intermediate magnetic pole layer 42.

On the other hand, as is clear from FIG. 7B, when the intermediate pole layer 42 is not used and the upper sub pole extending in the front-rear direction with the specified core width CW is directly connected to the upper pole layer 33, The overhang A PW can only be tolerated in a narrow range of 1.5 m to 2.5 xm. Since the path of the magnetic field lines is sharply narrowed between the upper magnetic pole layer and the upper auxiliary magnetic pole, it is considered that a large edge magnetic field is likely to be generated due to magnetic saturation.

In the future, when the core width CW of the upper sub pole 40 is further reduced, the intermediate pole layer 42 is interposed between the upper pole layer 33 and the upper sub pole 40, as shown in FIG. 8, for example. Meanwhile, the recording magnetic field decreases and the edge magnetic field increases. According to these trends, it will become difficult to reduce the core width CW of the upper sub pole 40 while maintaining the recording magnetic field of more than 470 kAZm and the edge magnetic field of less than 135 kAZm. It is expected to be.

On the other hand, when the upper pole layer 33 is formed by electrolytic plating using a photoresist as in the past, the upper pole layer 33 is reduced to about 1.2 or less along the track width direction. It is difficult to narrow. Therefore, as the core width CW of the upper sub-pole 40 is reduced, the overhang A PW of the upper pole layer 33 is inevitably increased. As described above, the edge magnetic field increases as the overhang A PW of the upper magnetic pole layer 33 increases.

Here, for example, when the core width CW of the upper sub pole 40 is changed while maintaining the width PW = 1.1 m of the upper pole layer 33 measured in the track width direction, the recording field Observe the magnetic field strength of the ridge magnetic field. The magnetic field strength was calculated using commercially available three-dimensional magnetic field analysis software as described above. The calculated simulation results are shown in FIG. 9 and FIG.

As shown in FIG. 9, in realizing the core width CW = 0.7 im of the upper sub-magnetic pole 40, the thickness SL of the upper sub-magnetic pole 40 may be set to, for example, more than 0.5 / m. In other words, the thickness S L of the upper sub pole 40 is the overhang amount APW (= 0.

It should just be set more than 2.5 times of 2). If the thickness SL of the upper sub pole 40 is set in this way, it is possible to suppress the edge magnetic field to less than 135 kAZm while securing sufficient magnetic field strength (about 470 kA / m or more) with the recording magnetic field. It becomes possible. Therefore, in recording information on the magnetic disk 13, problems such as blurring of recording of a recording track and magnetization reversal of a recording track adjacent to a target recording track can be eliminated. A narrow recording track is realized.

As shown in FIG. 10, in order to realize the core width CW of the upper sub-pole 40 of 0.5 m, the thickness SL of the upper sub-pole 40 may be set to 0.95 m or more, for example. In other words, the thickness S L of the upper sub pole 40 is the overhang amount APW (= 0.

3 um) should be set to about 3.17 times or more. If the thickness SL of the upper sub-pole 40 is set in this way, it is possible to suppress the edge magnetic field to less than 135 kAZm while securing a sufficient magnetic field strength (about 470 kA / m or more) with the recording magnetic field. It becomes possible. Therefore, when recording information on the magnetic disk 13, problems such as blurring of recording on a recording track and magnetization reversal of a recording track adjacent to a target recording track can be eliminated. As described above, a narrow recording track is realized.

Further, the saturation magnetic flux density Bs of the upper sub-pole 40 is changed while maintaining the width PW (= 0.8 / xm) of the upper pole layer 33 and the core width CW (= 0.5 urn) of the upper sub-pole 40. Then, observe the magnetic field strength of the recording magnetic field and the edge magnetic field. The magnetic field strength was calculated using commercially available three-dimensional magnetic field analysis software as described above. Figure 11 shows the calculated simulation results.

As shown in FIG. 11, the saturation magnetic flux density Bs of the upper auxiliary magnetic pole 40 may be set to, for example, 1.4 T or more. Thus, the saturation magnetic flux density B s of the upper sub pole 40 is set. If it is determined, it is possible to suppress the edge magnetic field to less than 135 kAZm while ensuring a sufficient magnetic field strength (about 470 kAZm or more) with the recording magnetic field. Therefore, when recording information on the magnetic disk 13, problems such as blurring of recording of a recording track and magnetization reversal of a recording track adjacent to a target recording track can be solved. In order to realize such a saturation magnetic flux density B s, the upper sub pole 40 is, for example, 50 N i 50 F e (B s = 1.4 T) or 45 N i 55 F e (B s = 1.6 T).

Next, a method of manufacturing the above-described inductive write head element 29 will be briefly described. First, an Altic wafer having a lower pole layer 31 formed on the surface is prepared. The lower magnetic pole layer 31 is laminated on the surface of the alumina layer in which the MR element 35 is embedded. A non-magnetic layer is subsequently laminated on the surface of the lower magnetic pole layer 31.

As shown in FIG. 12, a photoresist film 51 is formed on the surface of the nonmagnetic layer. In the photoresist film 51, voids 52a and 52b are formed, which form the upper sub-pole 40 and the intermediate pole layer 42. When the electroplating method is performed, the plating metal grows in the voids 52a and 52b. The upper sub pole 40 and the middle pole layer 42 are formed simultaneously. The plating metal grows along the plating base film laminated on the surface of the nonmagnetic layer prior to the formation of the photoresist film 51. In such an electrolytic plating method, a plating liquid reservoir 53 may be added to the voids 52a and 52b. According to such a plating solution reservoir 53, the plating solution can be surely made to enter the gap 52a that represents the narrow upper sub-pole 40. When the wafer on the plating solution pool 53 is scraped off, the floating surface 24 is exposed.

When the upper sub pole 40 and the middle pole layer 42 are formed in this way, as shown in FIG. 13A, ion milling is performed using the upper sub pole 40 and the middle pole layer 42 as a mask. Is done. As a result, the non-magnetic layer, that is, the gap layer 39 is cut off by the outer shapes of the upper sub pole 40 and the intermediate pole layer 42. At this time, on the surface of the lower magnetic pole layer 31, a lower auxiliary magnetic pole 38 similarly shaped as the outer shape of the upper auxiliary magnetic pole 40 and the intermediate magnetic pole layer 42 is cut out.

Thereafter, as shown in FIG. 13B, the surface of the lower magnetic pole layer 31 is coated with an alumina overcoat (insulating layer) 54. Such coatings include, for example, sputtering Processing may be used. As a result of the alumina particles uniformly falling on the surface of the lower magnetic pole layer 31, the upper auxiliary magnetic pole 40 rising from the lower magnetic pole layer 31 is buried in the bulge 55 rising from the surface of the alumina cover 54.

Subsequently, as shown in FIG. 13C, a flattening treatment is performed from the surface of the alumina cover 54. For this flattening process, for example, a polishing process may be used. The upper sub pole 40 is cut off from the tip together with the bulge 55, and as a result, the upper sub pole 40 buried in the aluminum bar coat 54 is exposed on the flat surface 56. The above-described conductive coil pattern 28 is formed on the flat surface 56 of the alumina overcoat 54 formed by such a flattening process. As a result, as is well known, a dense and accurate conductive coil pattern 28 can be realized. The conductive coil pattern 28 is newly coated with an alumina overcoat (not shown), and as a result, is embedded in the alumina film. The above-mentioned upper magnetic pole layer 33 is formed on the surface of the alumina film.

A step surface 58 may be formed on the tip piece 45 of the upper magnetic pole layer 33, for example, as shown in FIG. As is well known, such a stepped surface 58 can be formed by, for example, ion milling using a resist film. When such a step surface 58 is formed, the overhang amount APW of the upper pole layer 33 overhanging in the track width direction of the upper sub-pole 40 can be significantly reduced. If the overhang amount △ PW is reduced in this way, the edge magnetic field is reduced. However, since such a stepped surface 58 reduces the bonding area between the upper magnetic pole layer 33 and the upper auxiliary magnetic pole 40, the stepped surface 58 is formed near the contour of the intermediate magnetic pole layer 42. It is desirable to be interrupted. According to the formation of the step surface 58, the width PW of the upper magnetic pole layer 33 formed with the width PW of about 12 xm using the electrolytic plating method is equal to the PW = 1. 1 / im and PW = 0.8 xm can be reduced.

Claims

The scope of the claims

1. The upper sub-pole, which faces the medium facing surface at the front end and extends in the front-rear direction with a predetermined thickness along the reference surface, An intermediate magnetic pole layer that is largely defined in the width direction and an upper magnetic pole layer that is received on the surface of the intermediate magnetic pole layer and projects a predetermined amount in the track width direction from the upper auxiliary magnetic pole at the tip facing the medium facing surface. A thin-film magnetic head characterized in that the thickness of the upper sub pole is set to be at least 2.5 times the overhang of the upper pole layer.

2. The thin-film magnetic head according to claim 1, wherein the thickness is set to 3.17 times or more of an overhang amount.

3. The upper sub-pole, which faces the medium facing surface at the front end and extends in the front-rear direction with a predetermined thickness along the reference plane, and the rear end of the upper sub-pole extends along the reference plane from the rear end and has a track compared to the upper sub-pole An intermediate pole layer largely defined in the width direction, and an upper pole layer facing the medium facing surface at the front end and received on the surface of the intermediate pole layer. The saturation magnetic flux density of the upper sub pole is 1.4 T or more. A thin-film magnetic head characterized by being set to:

4. An upper sub-pole facing the medium facing surface at the front end and extending in the front-rear direction with a predetermined thickness along the reference plane, and a track extending from the rear end of the upper sub-pole along the reference plane to be wider than the upper sub-pole. An intermediate magnetic pole layer that is largely defined in the width direction and an upper magnetic pole layer that is received on the surface of the intermediate magnetic pole layer and projects a predetermined amount in the track width direction from the upper auxiliary magnetic pole at the tip facing the medium facing surface. A magnetic recording medium drive device characterized in that a thin-film magnetic head whose upper sub-pole has a thickness set to be at least 2.5 times the overhang of the upper pole layer is incorporated.

5. The upper sub-pole, which faces the medium facing surface at the front end and extends in the front-rear direction with a predetermined thickness along the reference plane, and the rear end of the upper sub-pole extends along the reference plane from the rear end and has a track compared to the upper sub-pole. An intermediate pole layer that is largely defined in the width direction, and faces the medium facing surface at the front end. And an upper magnetic pole layer received on the surface of the intermediate magnetic pole layer, and a thin-film magnetic head in which the saturation magnetic flux density of the upper auxiliary magnetic pole is set to 1.4 T or more is incorporated.