Abstract:
A method for manufacturing a magnetic head device that includes a soft magnetic layer includes the steps of forming a plating base layer in the soft magnetic layer through sputtering, and applying, during the forming step, a magnetic field in a direction parallel to an orientation fringe of a wafer in which the magnetic head device is formed.

Description:
[0001]    This application claims the right of foreign priority under 35 U.S.C. §119 based on Japanese Patent Application No. 2006-254419, filed on Sep. 20, 2006, which is hereby incorporated by reference herein in its entirety as if fully set forth herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to a magnetoresistive (“MR”) device, and more particularly to a structure of the MR device that has a hard bias film that applies a bias magnetic field, and applies the sense current perpendicular to a lamination surface of an MR film that serves as a read sensor film. The present invention is suitable, for example, for a read head for a hard disc drive (“HDD”). 
         [0003]    Along with the recent widespread Internet, a magnetic disc drive that stably records and reproduces a large amount of information including still and motion pictures has been increasingly demanded. When the surface recording density is increased so as to meet the large-capacity demand, the 1-bit area as the magnetically recorded information on the recording medium reduces, and the signal magnetic field from the recording medium becomes weaker. In order to read this weak signal magnetic field, a small and sensitive read head is needed. 
         [0004]    A current in plane (“CIP”)—giant magnetoresistive (“GMR”) head and a tunneling magnetoresistive (“TMR”) are known as this head. They use the MR device, applies the sense current perpendicular to the lamination surface of the MR device, and arrange a pair of permanent magnet films or hard bias films at both sides of the MR film so as to restrain noises. 
         [0005]    This type of MR device makes the hard bias film of such a magnetic material as CoPt alloy and CoCrPt alloy, and provides a pair of shield layers made, for example, of NiFe above and under the MR film to shield the external magnetic field. A nonmagnetic gap layer electrically insulates the hard bias films from the shield layers. The hard bias films, the shield layers, and the gap layer expose on the head&#39;s floatation surface of the MR device in addition to the MR film. 
         [0006]    Prior art include, for example, Japanese Patent Applications, Publication Nos. (“JP”) 5-62130 and 8-147633. 
         [0007]    In order to read the weak signal magnetic field, the head floating above the disc needs to be made closer to the disc, and the floatation surface of the MR device is more likely to collide with the disc due to the reduced head floatation amount. Then, due to the smear of the hard bias film, the bias magnetic field does not work parallel to the lamination surface of the sensor film, and the read sensitivity deteriorates. In addition, when the smear extends to the shield layer beyond the gap layer and the hard bias film and the shield layer are electrically connected to each other (short-circuited), the MR device that flows the sense current perpendicular to the lamination surface becomes defective. It is therefore necessary to protect the hard bias film for the stable recording and reproduction. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a MR device that can properly protect the hard bias film, a read head having the same, and a storage having the read head. 
         [0009]    A magnetoresistive device according to one aspect of the present invention includes a magnetoresistive film, and a pair of hard bias films that apply a bias magnetic field to the magnetoresistive film, sense current being flowing perpendicular to a lamination surface of the magnetoresistive film, and each hard bias film on a section parallel to the lamination surface being at least partially retreating from an exposure surface on which the magnetoresistive film exposes. According to the magnetoresistive device, the hard bias films retreat from the exposure surface, and are less likely to contact the external member and protected from the external impact. The exposure surface corresponds to the floatation surface when the magnetoresistive device is mounted on the head. 
         [0010]    For example, the pair of hard bias films on the section form an approximately convex shape that projects toward the exposure surface and is adjacent to the magnetoresistive film. This configuration can protect the hard bias films apart from the magnetoresistive film. Each hard bias film may at least partially retreat from the exposure surface by 10 nm. The hard bias film has an inclined surface on the section, the inclined surface inclining so as to separate from the exposure surface as a distance from the magnetoresistive film increases. The inclined surface is preferable because it can more easily maintain the bias magnetic field than the perpendicular surface that extends perpendicularly to the floatation surface. 
         [0011]    Preferably, the inclined surface is symmetrical with respect to a surface that halves the magnetoresistive film and is perpendicular to the exposure surface on the section. Thereby, the bias magnetic field can be easily maintained. An inclination angle of the inclined surface to the exposure surface is, for example, between 30° and 60°. The pair of hard bias films on the section may have a pair of horizontal surfaces parallel to and apart from the exposure surface, a pair of horizontal surfaces forming the same plane. Thereby, the bias magnetic field can be easily maintained. 
         [0012]    The magnetoresistive device may further include an insulating layer formed on a surface of each hard bias film at the side of the exposure surface, protecting the hard bias film from exposing from the exposure surface. The insulating layer is made, for example, of Al 2 O 3  or SiO 2 . 
         [0013]    A method according to another aspect of the present invention for manufacturing a magnetoresistive device that has a pair of hard bias films that apply a bias magnetic field to a magnetoresistive film, and flows sense current perpendicular to a lamination surface of the magnetoresistive film includes the steps of forming the hard bias films through sputtering, and forming an insulating layer on a side surface of the hard bias film at a side of an exposure surface on which the magnetoresistive film exposes. This manufacturing method can manufacture the magnetoresistive device that can exhibit the above operations. 
         [0014]    The magnetoresistive device manufactured by the above manufacturing method and a read head that includes the above magnetoresistive device, a current supplier that supplies the sense current, and a read part that reads a signal from a change of electric resistance of the magnetoresistive device in accordance with a signal magnetic field constitute one aspect of the present invention. A storage that includes a magnetic head part that includes the above read head and a write head, a driver that drives a magnetic recording medium to be recorded and reproduced by said magnetic head part also constitutes another aspect of the present invention. 
         [0015]    Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a plane view showing an internal structure of a HDD according to one embodiment of the present invention. 
           [0017]      FIG. 2  is an enlarged perspective view of a magnetic head part in the HDD shown in  FIG. 1 . 
           [0018]      FIG. 3A  is an enlarged plane view of a conventional layered structure of a head shown in  FIG. 2  when the head is viewed from its floatation surface. 
           [0019]      FIG. 3B  is a sectional view taken along a line A-A shown in  FIG. 3A . 
           [0020]      FIG. 4A  is an enlarged plane view of a layered structure of the head shown in  FIG. 2  according to a first embodiment of the present invention when the head is viewed from the floatation surface. 
           [0021]      FIG. 4B  is a sectional view taken along a line B-B shown in  FIG. 4A . 
           [0022]      FIG. 5A  is an enlarged plane view of a layered structure of the head shown in  FIG. 2  according to a second embodiment of the present invention when the head is viewed from the floatation surface. 
           [0023]      FIG. 5B  is a sectional view taken along a line C-C shown in  FIG. 5A . 
           [0024]      FIG. 6A  is a flowchart for manufacturing the conventional layered structure shown in  FIG. 3A . 
           [0025]      FIG. 6B  is schematic sectional and plane views of each step in the flowchart shown in  FIG. 6A . 
           [0026]      FIG. 7A  is a flowchart for manufacturing the layered structure of the second embodiment shown in  FIG. 5A . 
           [0027]      FIG. 7B  is schematic sectional and plane views of each step in the flowchart shown in  FIG. 7A . 
           [0028]      FIG. 8A  is a flowchart of a variation of the method shown in  FIG. 7A . 
           [0029]      FIG. 8B  is schematic sectional and plane views of each step in the flowchart shown in  FIG. 8A . 
           [0030]      FIG. 9A  is a flowchart of another variation of the method shown in  FIG. 7A . 
           [0031]      FIG. 9B  is schematic sectional and plane views of each step in the flowchart shown in  FIG. 9A . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]    Referring now to the accompanying drawings, a description will be given of a HDD  100  according to one embodiment of the present invention. The HDD  100  includes, as shown in  FIG. 1 , one or more magnetic discs  104  each serving as a recording medium, a spindle motor  106 , and a head stack assembly (“HSA”)  110  in a housing  102 . Here,  FIG. 1  is a schematic perspective view showing the internal structure of the HDD  100 . 
         [0033]    The housing  102  is made, for example, of aluminum die cast base and stainless steel, and has a rectangular parallelepiped shape, to which a cover (not shown) that seals the internal space is joined. The magnetic disc  104  has a high surface recording density, such as 100 Gb/in 2  or greater. The magnetic disc  104  is mounted on a spindle hub of the spindle motor  106  through its center hole. 
         [0034]    The spindle motor  106  has, for example, a brushless DC motor (not shown) and a spindle as its rotor part. For instance, two magnetic discs  104  are used in order of the disc, a spacer, the disc and a clamp stacked on the spindle, and fixed by bolts coupled with the spindle. 
         [0035]    The HSA  110  includes a magnetic head part  120 , a carriage  170 , a base plate  178 , and a suspension  179 . 
         [0036]    The magnetic head part  120  includes a slider  121 , and a head device built-in film  123  that is joined with an air outflow end of the slider  121  and has a read/write head  122 . 
         [0037]    The slider  121  has an approximately rectangular parallelepiped shape, and is made of Al 2 O 3 —TiC (Altic). The slider  121  supports the head  122  and floats from the surface of the disc  104 . The head  122  records information in and reproduces information from the disc  104 . The surface of the slider  121  opposing to the magnetic disc  104  serves as a floatation surface  125 , which receives an airflow  126  that occurs with rotations of the magnetic disc  104 . Here,  FIG. 2  is a schematic perspective view of the magnetic head part  120 . 
         [0038]      FIG. 3A  is an enlarged plane view of the conventional head.  FIG. 4A  is an enlarged plane view of the head  122  according to a first embodiment of the present invention.  FIG. 5A  is an enlarged plane view of the head  122  according to a second embodiment of the present invention. 
         [0039]    The head  122  is, for example, a MR/inductive composite head that includes an inductive head device  130  that writes binary information in the magnetic disc  104  utilizing the magnetic field generated by a conductive coil pattern (not shown), and an MR head  140  that reads the binary information based on the resistance that varies in accordance with the magnetic field applied by the magnetic disc  104 . 
         [0040]    The conventional head shown in  FIG. 3A  has the inductive head device  130  and an MR head device  10 . The head shown in  FIG. 4A  has the inductive head device  130  and the MR head device  140 . The head shown in  FIG. 5A  has the inductive head device  130  and the MR head device  140 A.  FIGS. 3A ,  4 A, and  5 B are schematic plane views of the MR head devices  10 ,  140  and  140 A viewed from the floatation surface  125 . 
         [0041]    The inductive head device  130  includes a nonmagnetic gap layer  132 , an upper magnetic pole layer  134 , an insulating film  136  made of an Al 2 O 3  film, and an upper shield-upper electrode layer  139 . As discussed later, the upper shield-upper electrode layer  139  also constitutes part of the MR head device  10 ,  140 , or  140 A. 
         [0042]    The nonmagnetic gap layer  132  spreads over a surface of the upper shield-upper electrode layer  139 , and is made, for example, of Al 2 O 3 . The upper magnetic pole layer  134  opposes to the upper shield-upper electrode layer  139  with respect to the nonmagnetic gap layer  132 , and is made, for example, of NiFe. The insulating film  136  extends over a surface of the nonmagnetic gap layer  132 , covers the upper magnetic pole layer  134 , and forms the head-device built-in film  123 . The upper magnetic pole layer  134  and upper shield-upper electrode layer  139  cooperatively form a magnetic core in the inductive write head device  130 . The lower magnetic pole layer in the inductive write head device  130  serves as the upper shield-upper electrode layer  139  in the MR head device  140 . As the conductive coil pattern induces a magnetic field, a magnetic-flux flow between the upper magnetic pole layer  134  and upper shield-upper electrode layer  139  leaks from the floatation surface  125  due to acts of the non-magnetic gap layer  132 . The leaking magnetic-flux flow forms a signal magnetic field or gap magnetic field. 
         [0043]    The conventional MR head device  10  includes, as shown in  FIG. 3A , the upper shield layer  139 , a lower shield layer  142 , an upper gap layer  144 , a lower gap layer  146 , an MR film  150 , and a pair of hard bias films  160  that are provided at both sides of the MR film  150 . 
         [0044]    The MR head device  140  includes, as shown in  FIG. 4A , the upper shield layer  139 , the lower shield layer  142 , the upper gap layer  144 , the lower gap layer  146 , the MR film  150 , the pair of hard bias films  160 A that are provided at both sides of the MR film  150 , and an insulating layer  169 . The MR head devices  140  and  10  are different from each other in that the MR head device  140  has the hard bias films  160 A whereas the MR head device  10  has the hard bias film  160 , and the MR head device  140  has the insulating layer  169  whereas the MR head device  10  has no insulating layer. 
         [0045]    The MR head device  140 A includes, as shown in  FIG. 5A , the upper shield layer  139 , the lower shield layer  142 , the upper gap layer  144 , the lower gap layer  146 , the MR film  150 , a pair of hard bias films  160 B that are provided at both sides of the MR film  150 , and an insulating layer  169 A. The MR head devices  140 A and  10  are different from each other in that the MR head device  140 A has the hard bias films  160 B whereas the MR head device  10  has the hard bias film  160 , and the MR head device  140 A has the insulating layer  169 A whereas the MR head device  10  has no insulating layer. 
         [0046]    The shield layers  139  and  142  are made, for example, of NiFe. The gap layers  144  and  146  are made of an insulating material, such as Ta and Al 2 O 3 . 
         [0047]    The MR film  150  is made, for example, of a TMR film, which includes, in order from the bottom in  FIGS. 3A ,  4 A and  5 A, a free ferromagnetic layer  152 , a nonmagnetic insulating layer  154 , a pinned magnetic layer  156 , and an antiferromagnetic layer  158 . The TMR film has a ferromagnetic tunneling junction configured to hold the insulating layer  154  between the two ferromagnetic layers, and uses a tunneling phenomenon in which the electrons in the minus side ferromagnetic layer pass through the insulating layer to the plus side ferromagnetic layer, when the voltage is applied between the two ferromagnetic layers. The insulating layer  154  uses, for example, an Al 2 O 3  film. 
         [0048]    The MR film  150  may be a spin-valve film. In that case, the MR device becomes a CPP-GMR device, and includes, in order from the bottom shown in  FIGS. 3A ,  4 A, and  5 A, a free layer  152 , a nonmagnetic intermediate layer  154 , a pinned magnetic layer  156 , and an exchange-coupling (antiferromagnetic) layer  158 . Usually, a protective layer and a nonmagnetic primary coat, such as Ta, are added above the exchange-coupling layer and under the free layer. In addition, the spin-valve film  150  may have any types including a top-type spin-valve structure, a bottom-type spin-valve structure, and a dual spin valve structure. 
         [0049]    Thus, the MR head device  10 ,  140 , or  140 A has a CPP structure that applies the sense current perpendicular to the lamination surface of the MR film  150  or parallel to the lamination direction, as shown by an arrow CF. 
         [0050]    The hard bias film  160  generates a bias magnetic field that restrains noises. The hard bias film  160  is made, for example, of such a magnetic material as CoPt alloy and CoCrPt alloy. This embodiment makes the hard bias film  160  of CoCrPt alloy. Usually, a primary coat, such as Cr, CrTi alloy and TiW alloy, is added to the hard bias film  160 . For the CPP-GMR device, the insulating film is layered on the hard bias film  160 . 
         [0051]      FIG. 3B  is a sectional view taken along a line A-A in  FIG. 3A  or a schematic plane view of the hard bias film  160  and the MR film  150  before the upper gap layer  144  and the upper shield layer  139  shown in  FIG. 3A  are layered. Similarly,  FIG. 4B  is a sectional view taken along a line B-B in  FIG. 4A  or a schematic plane view of the hard bias film  160 A, the insulating layer  169 , and the MR film  150  before the upper gap layer  144  and the upper shield layer  139  shown in  FIG. 4A  are layered.  FIG. 5B  is a sectional view taken along a line C-C in  FIG. 5A  or a schematic plane view of the hard bias film  160 B, the insulating layer  169 A, and the MR film  150  before the upper gap layer  144  and the upper shield layer  139  shown in  FIG. 5A  are layered. In  FIGS. 3B ,  4 B and SB, the bottom surface is the floatation surface  125  and serves as the exposure surface, on which the MR film  150  exposes. 
         [0052]    The hard bias films  160  of the conventional MR device  10  expose on the floatation surface  125 . Therefore, as shown in  FIG. 3A , the hard bias films  160  collide with the disc  104  on the floatation surface  125 , and smears S 1  and S 2  are likely to occur. The smear S 1  short-circuits the hard bias film  160  to the upper shield layer  139 , and the smear S 2  short-circuits the hard bias film  160  to the lower shield layer  142 . As a result, the sense current does not properly flow through the MR film  150 , and the MR head device  10  is likely to be defective. In particular, the head&#39;s floatation amount would reduce for the future high recording-density disc, and the hard bias films  160  are highly likely to collide with the disc  104 . 
         [0053]    On the other hand, the hard bias films  160 A and  160 B at least partially retreat from the floatation surface or exposure surface  125 . The hard bias films  160 A expose on the floatation surface  125  in the area  161 , and retreat or space from the floatation surface  125  in the areas  162  and  163 . In other words, the hard bias films  160 A do not expose from the floatation surface  125  in the areas  162  and  163 . The hard bias films  160 B have substantially no exposing part from the floatation surface  125 , and retreat or space from the floatation surface  125  in the areas  164  and  165 . In the MR head devices  140  and  140 A, the hard bias films  160 A and  160 B retreat from the floatation surface  125 , are less likely to contact the disc  104 , and are protected from the external impacts. 
         [0054]    A smaller horizontal length is preferable for the area  161  shown in  FIG. 4B .  FIG. 5B  shows that the area  161  has no horizontal length. However, it is difficult in view of the cost and manufacturing technology to eliminate the horizontal length of the area  161 . Accordingly, the present invention allows a slight horizontal length of the area  161 . 
         [0055]    A pair of hard bias films  160 A have, as shown in  FIG. 4B , an approximately convex shape that projects to the floatation surface  125  side in the areas  161  and  162  as adjacent parts to the MR film  150 . A pair of hard bias films  160 B have, as shown in  FIG. 5B , an approximately convex shape that projects to the floatation surface  125  side in the area  164  as adjacent part to the MR film  150 . Thereby, the hard bias films  160 A and  160 B are protected in the areas  163  and  165  apart from the MR film  150 . 
         [0056]    10 nm is enough for retreat amounts L 1  and L 2  of the hard bias amounts  160 A and  160 B in the areas  163  and  165 . 
         [0057]    The hard bias film  160 A has an area  162  with an inclined surface  162   a  on the floatation surface  125  side, and the inclined surface  162   a  inclines so as to separate from the floatation surface  125  as a horizontal distance from the MR film  150  increases. The hard bias film  160 B has an area  164  with an inclined surface  164   a  on the floatation surface  125  side, and the inclined surface  164   a  inclines so as to separate from the floatation surface  125  as a horizontal distance from the MR film  150  increases. The inclined surfaces  162   a  and  164   a  are preferable because they can more easily maintain the bias magnetic field than the perpendicular surfaces (or the inclined surfaces with an angle θ of 90° in  FIGS. 4B and 5B ), which extend perpendicularly to the floatation surface  125 . The inclination angle θ of the inclined surfaces  162   a  and  164   a  are preferably maintained between 30° and 60°. The angle greater than 60° has a difficulty in maintaining the bias magnetic field, and the angle smaller than 30° cannot maintain a sufficient retreat amount of the hard bias film from the floatation surface  125 . 
         [0058]    The hard bias film  160 A has an area  163  having a horizontal surface  163   a  on the side of the floatation side  125 , and the horizontal surface  163   a  is parallel to and retreats from the floatation surface  125 . In addition, the hard bias film  160 B has an area  165  having a horizontal surface  165   a  on the side of the floatation side  125 , and the horizontal surface  165   a  is parallel to and retreats from the floatation surface  125 . 
         [0059]    The inclined surface  162   a  and the horizontal surface  163   a  are symmetrical with respect to a surface P 1  that is perpendicular to the floatation surface  125 , and halves the MR film  150  on the section shown in  FIG. 4B . The inclined surface  164   a  and the horizontal surface  165   a  are symmetrical with respect to a surface P 2  that is perpendicular to the floatation surface  125 , and halves the MR film  150  on the section shown in  FIG. 5B . 
         [0060]    The horizontal lengths of the areas  162  and  164  suffer no restriction. The hard bias films  160  and  160 A do not have to have the horizontal surfaces  163   a  and  165   a.    
         [0061]    The MR device  140  has the insulating layer  169  that is formed on the side surface of the hard bias films  160 A on the floatation surface  125  side (i.e., on the inclined surface  162   a  and the horizontal surface  163   a ). The MR device  140 A has the insulating layer  169 A that is formed on the side surface of the hard bias film  160 A on the floatation surface  125  side (i.e., on the inclined surface  164   a  and the horizontal surface  165   a ). Thereby, the insulating layer  169  prevents the hard bias films  160 A from exposing on the floatation surface  125 , and the insulating layer  169 A prevents the hard bias films  160 B from exposing on the floatation surface  125 . The insulating layers  169  and  169 A are made, for example, of Al 2 O 3  or SiO 2 . When the lower gap layer  146 , and the insulating layers  169  and  169 A are made of Al 2 O 3 , boundaries are invisible between the lower gap layer  146  and the insulating layer  169  in  FIG. 4A  and between the lower gap layer  146  and the insulating layer  169 A in  FIG. 5A . 
         [0062]    Referring now to  FIGS. 6A and 6B , a description will be given of a method for manufacturing the conventional MR head device  10 . Here,  FIG. 6A  us a flowchart for manufacturing the MR head device  10  shown in  FIG. 3A .  FIG. 6B  is a schematic plane view of each step in the flowchart shown in  FIG. 6A . 
         [0063]    Referring to  FIG. 6A , the lower shield layer  142  is formed through plating via the Al 2 O 3  layer that is formed on the Altic substrate through sputtering (step  1002 , left top sectional view in  FIG. 6B ). Next, an alumina (Al 2 O 3 ) layer is formed through sputtering (step  1004 , left second sectional view from the top in  FIG. 6B ). Next, the MR film  150  is formed through sputtering (step  1006 , left third sectional view from the top in  FIG. 6B ). 
         [0064]    Next, the MR film  150  is etched through ion milling via the application of the resist R (step  1008 , left fourth sectional view from the top in  FIG. 6B ). A right top enlarged plane view in  FIG. 6B  shows an E 1  part near the MR film  150  of that state. 
         [0065]    Next, the lower gap film  146  and the hard bias film  160  are formed through sputtering (step  1010 , left third sectional view from the bottom in  FIG. 6B ). A right second enlarged plane view from the top in  FIG. 6B  shows an E 2  part near the MR film  150  of that state. The MR film  150  is provided between and around the hard bias films  160 . The hard bias films  160  at both sides of the MR film  150  each have a rectangular shape with two adjacent chambered corners. A pair of hard bias films  160  are arranged so that two sides each having the chamfered corners at both ends oppose to each other. 
         [0066]    Next, the rectangular resist R is applied to the hard bias films  160  and unnecessary part is removed from the MR film  150  so as to form the final region (step  1012 ). A right second plane view from the bottom in  FIG. 6B  shows the resist R applied to the hard bias film  160 . The resist R covers the center between a pair of hard bias films  160  so as to remove the MR film  150  outside this area. A width of the rectangular resist R determines a width of the MR film  150 , and a shape of the other part is not limited to the rectangle. In addition, a right bottom enlarged plane view in  FIG. 6B  shows the MR film  150  and the hard bias film  160  from which the resist R is removed. It is understood that an area of the MR film  150  is limited to the center between a pair of hard bias films  160 . The shape is finally cut in a lateral direction, and becomes as shown in  FIG. 3B . 
         [0067]    Next, the Al 2 O 3  layer is formed through sputtering (step  1014 , left second sectional view from the bottom in  FIG. 6B ). Next, the upper gap layer  144  is formed through sputtering, and the upper shield layer  139  is formed through plating (step  1016 , left bottom sectional view in  FIG. 6B ). 
         [0068]    Referring now to  FIGS. 7A and 7B , a description will be given of a method for manufacturing the MR head device  140 A shown in  FIG. 5A . Unless the area  161  is eliminated, this manufacturing method is applicable to the MR head device  140  shown in  FIG. 5A . Here,  FIG. 7A  is a flowchart for manufacturing the MR head device  140 A.  FIG. 7B  is a schematic plane view of each step in the flowchart shown in  FIG. 7A . Those steps in  FIG. 7A , which are the same as the corresponding steps in  FIG. 6A , are designated by the same reference numerals, and a duplicate description will be omitted. The flowchart shown in  FIG. 7A  is different from that shown in  FIG. 6A  in that the flowchart shown in  FIG. 7A  has the steps  1020  to  1024  instead of the steps  1008  to  1012 . 
         [0069]    The step  1020  etches the MR film  150  through ion milling via the resist application. 
         [0070]    Next, the lower gap layer  146  and the hard bias film  160 B are formed through sputtering (step  1022 ). A left fourth sectional view from the bottom in  FIG. 7B  shows the state before the hard bias film  160 B is formed. A right top enlarged plane view in  FIG. 7B  shows an F 2  part near the MR device  150  after the hard bias film  160 B is formed. It is understood that the right top plane view in  FIG. 7B  is different in shape from the right second plane view from the top in  FIG. 6B . The MR film  150  is formed between and around the hard bias films  160 B. In  FIGS. 7A and 7B , the hard bias films  160 B formed at both sides of the MR film  150  have a shape that combines a rectangle with a parallelogram. A pair of hard bias films  160 B are arranged so that the bent parts oppose to each other. 
         [0071]    Next, the resist R is applied to the hard bias films  160 B to remove unnecessary part from the MR film  150  through ion milling, and to create the final region. The insulating film  169 A is formed on the side surface (i.e., on the inclined surface  164   a  and the horizontal surface  165   a ) of the hard bias film  160 B through sputtering (step  1024 , left third sectional view from the bottom in  FIG. 7B ). In that case, the right second plane view from the bottom in  FIG. 7B  shows the resist R applied to the hard bias films  160 B. The resist R covers the lower side between a pair of hard bias films  160 B, and the part other than this region is removed from the MR film  150 . It is understood that the right second plane view from the bottom in  FIG. 7B  is different from the right plane view from the bottom in  FIG. 6B  in a shape of the resist R. The resist R has a similar shape to the hard bias film  160 B, but is connected at the center bottom so as to cover the center bottom of the hard bias film  160 B. 
         [0072]    The left third sectional view from the bottom in  FIG. 7B  shows the MR film  150  and the hard bias film  160 B after the resist R is removed, and the right bottom view in  FIG. 7B  is its plane view. It is understood that the region of the MR film  150  is limited to the lower side between a pair of hard bias film  160 B, and that the insulating layer  169 A is as level as the hard bias films  160 B. The step  1024  protects the inclined surface  164   a  and the horizontal surface  165   a  of the hard bias film  160 B. 
         [0073]    While  FIGS. 7A and 7B  limit the region of the MR film  150  after the hard bias films  160 B are formed, the final regions of the MR film  150  and the hard bias film  160 B may be formed simultaneously. Referring now to  FIGS. 8A and 8B , a manufacturing method of that embodiment will be described. Here,  FIG. 8A  is a flowchart for manufacturing the MR head device  140 A.  FIG. 8B  is a schematic plane view of each step in  FIG. 8A . Those steps in  FIG. 8A , which are the same as corresponding steps in  FIG. 6A , are designated by the same reference numerals, and a duplicate description will be omitted. The flowchart shown in  FIG. 8A  is different from that shown in  FIG. 6A  in that the flowchart shown in  FIG. 8A  has the steps  1030  and  1032  instead of the step  1012 . 
         [0074]    The step  1030  forms the final regions of the hard bias film  160 B and the MR film  150 . In other words, this step forms the hard bias film  160 B shown in the right top view in  FIG. 8B  similar to the right second view from the top in  FIG. 6B . Next, this step forms, on the hard bias film  160 B, the resist R that has the same shape as the resist R in the right second view in  FIG. 7B  so that the upper end of the resist R accords with the upper end of the hard bias film  160 B. Parts of the MR film  150  and the hard bias film  160 B are simultaneously removed through ion milling. The right second plane view from the bottom in  FIG. 8B  shows the resist R applied onto the hard bias film  160 B. 
         [0075]    Next, the insulating layer  169 A is formed through sputtering on the side surface of the hard bias film  160 B (i.e., the inclined surface  164   a  and the horizontal surface  165   a  shown in  FIG. 5B ) (step  1032 , left third sectional view from the bottom shown in  FIG. 8B ). The left third sectional view from the bottom in  FIG. 8B  shows the hard bias film  160 B and the MR film  150  after the resist R is removed, and the right bottom plane view in  FIG. 8B  is its plane view. It is understood that the region of the MR film  150  is limited to the lower end between a pair of hard bias films  160 B. The insulating layer  169 A is formed as level as the hard bias films  160 B. The step  1032  protects the inclined surface  164   a  and the horizontal surface  165   a  of the hard bias film  160 B. 
         [0076]    Alternatively, as another variation of the manufacturing method shown in  FIGS. 6A and 6B , the final region of the hard bias film  160 B can be made after the final region of the MR film  150  may be formed. Referring now to  FIGS. 9A and 9B , a description of an illustration of the manufacturing method will be given. Here,  FIG. 9A  is a flowchart for manufacturing the MR head device  140 A.  FIG. 9B  is a schematic plane view of each step in the flowchart shown in  FIG. 9A . Those steps in  FIG. 9A , which are the same as corresponding steps in  FIGS. 6A and 8A , are designated by the same reference numerals, and a duplicate description will be omitted. The flowchart shown in  FIG. 9A  is different from that shown in  FIG. 6A  in that the flowchart shown in  FIG. 9A  has the steps  1040 - 1042  after the step  1012 . 
         [0077]    The step  1012  creates the final region of the MR film  150 . Here, the final region of the MR film  150  is created at the center between a pair of hard bias films  160  in a manner similar to the four right plane views in  FIG. 6B . Three right top plane views in  FIG. 9B  are the same as three right bottom plane views in  FIG. 6B . 
         [0078]    Next, the final region of the hard bias film  160 B is created (step  1040 ). More specifically, the right third resist R from the top in  FIG. 9B  is formed on the hard bias films  160 B so that the upper end of the resist R accords with the upper end of the hard bias film  160 B, and part of the hard bias film  160 B is removed through ion milling. The right second plane view from the bottom in  FIG. 9B  shows the resist R applied to the hard bias films  160 B in that state. The right second plane view from the bottom in  FIG. 9B  is different from the right second plane view from the bottom in  FIG. 7B  in a shape of the applied resist R, but both shapes may be the same. In the right second plane view from the bottom in  FIG. 9B , the resist R has a shape that combines an isosceles triangle with the center of the rectangle. In the right second plane view from the bottom in  FIG. 7B , the resist R has a Y-shaped concave on the side opposite to the isosceles triangle of the resist R in the right second plane view from the bottom in  FIG. 9B . 
         [0079]    Next, the step  1032  follows. 
         [0080]    It is understood that also in  FIGS. 9A and 9B , the region of the MR film  150  is limited to the lower end between a pair of hard bias films  160 B, and that the insulating layer  169 A is formed as level as the hard bias films  160 B. The step  1032  protects the insulated surface  164   a  and the horizontal surface  165   a  of the hard bias film  160 B. 
         [0081]    Turning back to  FIG. 1 , the carriage  170  serves to rotate or swing the magnetic head part  120  in the arrow directions shown in  FIG. 1 , and includes a voice coil motor (not shown), a shaft  174 , a flexible printed circuit board (“FPC”)  175 , and an arm  176 . 
         [0082]    The voice coil motor has a flat coil between a pair of yokes. The flat coil opposes to a magnetic circuit (not shown) provided to the housing  102 , and the carriage  170  swings around the shaft  174  in accordance with values of the current that flows through the flat coil. The magnetic circuit includes, for example, a permanent magnet fixed onto an iron plate fixed in the housing  102 , and a movable magnet fixed onto the carriage  170 . 
         [0083]    The shaft  174  is inserted into a hollow cylinder in the carriage  170 , and extends perpendicular to the paper surface of  FIG. 1  in the housing  102 . The FPC  175  provides the wiring part with a control signal, a signal to be recorded in the disc  104 , and the power, and receives a signal reproduced from the disc  104 . 
         [0084]    The arm  176  is an aluminum rigid body, and has a perforation hole at its top. The suspension  179  is attached to the arm  176  via the perforation hole and the base plate  178 . 
         [0085]    The base plate  178  serves to attach the suspension  179  to the arm  176 , and includes a welded section, and a dent or dowel. The welded portion is laser-welded with the suspension  179 . The dent is a part to be swaged with the arm  176 . 
         [0086]    The suspension  179  serves to support the magnetic head part  120  and to apply an elastic force to the magnetic head part  120  against the magnetic disc  104 , and is, for example, a stainless steel suspension. The suspension  179  has a flexure (also referred to as a gimbal spring or another name) which cantilevers the magnetic head part  120 , and a load beam (also referred to as a load arm or another name) which is connected to the base plate  178 . The load beam has a spring part at its center so as to apply sufficient compression force in the Z direction. The suspension  179  also supports a wiring part that is connected to the magnetic head part  120  via a lead etc. 
         [0087]    In operation of the HDD  100 , the spindle motor  106  rotates the disc  104 . The airflow associated with the rotations of the disc  104  is introduced between the disc  104  and slider  121 , forming a fine air film and thus generating the floating force that enables the slider  121  to float over the disc surface. The suspension  179  applies the elastic compression force to the slider  121  against the floating force of the slider  121 . As a result, a balance is formed between the floating force and the elastic force. 
         [0088]    This balance spaces the magnetic head part  120  from the disc  104  by a constant distance. Next, the carriage  170  rotates around the shaft  174  for head&#39;s seek for a target track on the disc  104 . In writing, data that is received from a host such as a PC, modulated and amplified is supplied to the inductive head device  130 . Thereby, the inductive head device  130  writes down the data onto the target track. In reading, the sense current is supplied to the MR head device  140 , and the MR head device  140  reads desired information from the desired track on the disc  104 . The MR head device  140  sensitively and stably reads the signal magnetic field because its hard bias films are protected. 
         [0089]    Further, the present invention is not limited to these preferred embodiments, and various modifications and variations may be made without departing from the spirit and scope of the present invention. For example, the present invention is applicable, in addition to a magnetic head, to a magnetic sensor, such as a magnetic potentiometer that detects a displacement and an angle, reading of a magnetic card, and recognition of a paper bill printed in magnetic ink. 
         [0090]    Thus, the present invention can provide a method of manufacturing a highly sensitive magnetic head device having a good shield characteristic.