Patent Publication Number: US-2007121246-A1

Title: Thin-film magnetic head for perpendicular recording and method of manufacturing the same

Description:
This application claims the benefit of Japanese Patent Application No. 2005-345752 filed Nov. 30, 2005, which is hereby incorporated by reference.  
     BACKGROUND  
      1. Field  
      The present embodiments relate to a thin-film magnetic head and a method of manufacturing the thin-film magnetic head.  
      2. Related Art  
      A perpendicular recording magnetic head applies perpendicular magnetic field to a recording medium and perpendicularly magnetizes the head of the recording medium is known in the related arts (see JP-A-5-174332, JP-A-2001-101627, JP-A-2003-6819).  
      In conventional perpendicular recording magnetic heads, for example, according to a solenoidal type thin-film magnetic head, a perpendicular recording magnetic head is formed on a reading head. A reading head includes a reading element, a first coil layer, a main pole for recording, a second coil layer, and a recording head that has a return yoke formed in this order on the trailing end of a slider formed of a non-magnetic material. The main pole and the return yoke layer are connected at the end in a height direction and the first and second coils are connected such that they form a solenoidal coil wound around the main pole.  
      Conventionally, when a shield layer of a reading head and the main pole of a recording head and a return yoke layer have different potential process damage appears in a process of manufacturing a magnetic head. An exemplary process can be a waf process, or SLD/HGA process. Exemplary process damage can be corrosion or etching.  
      In the related art, in order to maintain a reading head and a main pole and a return yoke layer with the same potential, various types of configurations have been proposed, such as a configuration in which a conductive layer that contacts with a return yoke layer is provided and exposed to a medium-contacting surface (see JP-A-5-174332), or a configuration in which a non-magnetic metal layer is provided on an upper shield layer of a reading head and comes in contact with a main pole (see JP-A-2003-6819). However, according to the above configurations, new elements and processes for providing new layers should be added, thus additional layers and processes are required.  
     SUMMARY  
      The present embodiments may obviate one or more of the drawbacks inherent in the related art. For example, in one embodiment, a thin-film magnetic head maintains a reading head and a recording head in the same potential and has a simple configuration.  
      In one embodiment, a thin-film magnetic includes a reading head that includes a reading element and a writing head that is formed above the reading head. The writing head includes a first magnetic part and a second magnetic part that are connected with each other with a gap therebetween at a predetermined distance in a height direction side, which is higher than a surface that faces a recording medium and a solenoidal coil layer that is formed by connecting ends of a first coil layer formed between the first magnetic part and the reading head and a second coil layer formed between the first and second magnetic parts in a track width direction and by winding the first and second coil layers around the first magnetic part.  
      In this embodiment, a coil insulating layer is formed on a shield layer of the reading head. A connecting hole that exposes a part of the shield layer is formed at a predetermined position of the coil insulating layer beyond the region for forming the first coil layer in the height direction. The first coil layer is formed on the coil insulating layer. A conductive layer made of the same non-magnetic material as the first coil layer is formed on the shield layer that serves as a bottom of the connecting hole. A first coil insulating layer is formed over the first coil layer and the conductive layer, while exposing the upper surface of the conductive layer. The first magnetic part is formed on the first coil insulating layer and electrically connected with the conductive layer.  
      In one embodiment, a thin-film magnetic head includes a reading head that includes a reading element and a writing head formed above the reading head. The writing head includes a first magnetic part and a second magnetic part that are connected with each other with a gap therebetween at a predetermined distance from a recording medium-facing surface in the height direction and a solenoidal coil layer that is formed by connecting ends of a first coil layer formed between the first magnetic part and the reading head and a second coil layer formed between the first and second magnetic parts in a track width direction and winding the first and second coil layers around the first magnetic part.  
      According to another embodiment, a method of manufacturing the thin-film magnetic head includes forming a coil insulating layer on a shield layer of the reading head; forming a connecting hole for exposing a part of the shield layer at a predetermined region of the coil insulating layer beyond the region for forming the first coil layer in the height direction; simultaneously forming the first coil layer on the coil insulating layer, and a conductive layer made of the same non-magnetic material as the first coil layer on the shield layer that serves as a bottom of the connecting hole; forming a first coil insulating layer over the first coil layer and the conductive layer, while exposing the upper surface of the conductive layer; and forming the first magnetic part on the first coil insulating layer so that the first magnetic part is electrically connected with the conductive layer.  
      In another embodiment, a contact layer may be simultaneously formed on the upper surfaces of both ends of the first coil layer in the track width direction and on the upper surface of the conductive layer, after the first coil layer and a conductive layer are simultaneously formed on the coil insulating layer and on the shield layer that serves as a bottom of the connecting hole, respectively.  
      In one embodiment, because shield layer of a reading head and a magnetic pole of a writing head are electrically connected through a conductive layer, the reading and writing heads have the same potential. In this embodiment, for example, corrosion or etching, does not appear in the manufacturing process.  
      In another embodiment, a conductive part can be simultaneously formed in a process for manufacturing a first coil layer. In this embodiment, the required process does not increase and productivity is not deteriorated. The first coil layer and the conductive layer are simultaneously formed of the same non-magnetic material, so that no additional material is needed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic vertical cross-sectional view of one embodiment of a perpendicular recording magnetic head;  
       FIG. 2  is a vertical cross-sectional view of one embodiment of a step of manufacturing process of the perpendicular recording magnetic head;  
       FIG. 3  is a vertical cross-sectional view of one embodiment of the manufacturing process of the perpendicular recording magnetic head;  
       FIG. 4   a  is a vertical cross-sectional view and  4   b  is a front view seen from a surface that faces a recording medium showing the next step of one embodiment of the perpendicular recording magnetic head;  
       FIG. 5   a  is a vertical cross-sectional view and  5   b  is a front view seen from the surface that faces the recording medium of one embodiment of the perpendicular recording magnetic head;  
       FIG. 6   a  is a vertical cross-sectional view and  6   b  is a front view seen from the recording medium-facing surface that shows of one embodiment of the perpendicular recording magnetic head; and  
       FIG. 7   a  is a vertical cross-sectional view and  7   b  is a front view seen from the recording medium-facing surface that shows of one embodiment of the perpendicular recording magnetic head. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  is a schematic vertical cross-sectional view that shows a perpendicular recording magnetic head according to one embodiment. A perpendicular recording magnetic head  10 , called a perpendicular magnetic head, applies a perpendicular magnetic field to a recording medium M by using a writing head HW that faces the recording medium M and perpendicularly magnetizes the hard film of the recording medium M. The writing head HW is formed on a reading head HR.  
      The perpendicular recording magnetic head  10  has a slider  11  formed of a non-magnetic material, for example, Al 2 O 3 , Tic, or the like. A recording medium-facing surface  11   a  of the slider  11  faces the recording medium M. As the recording medium M rotates, the slider  11  rises from the surface of the recording medium M due to the air flow on the surface and is held at a predetermined distance from the recording medium M.  
      Referring to  FIG. 1 , the X-axis is perpendicular to the figure, the Y-axis is perpendicular to a direction of arrow A and parallel with the figure, and the Z-axis is parallel and opposite to the direction of arrow A. The Y-axis direction is the height direction.  
      Referring to  FIG. 1 , in the perpendicular magnetic recording head  10 , each component is formed in the Z-axis direction (opposite to the arrow A) on the trailing end  11   b  of the slider  11 . A non-magnetic insulating layer  12  of an inorganic material, for example, Al 2 O 3 , SiO 2 , or the like, is formed on the trailing end  1   b  of the slider  11  and the reading head HR is formed on the non-magnetic insulating layer  12 . The reading head HR has a lower shield layer  13 , an upper shield layer  16 , and a reading element  14  embedded in a non-magnetic insulating layer (gap insulating layer) between the lower and upper shield layers  13  and  16 . The reading element  14  is a magnetic reluctance element, for example, AMR, GMR, TMR, or the like. The writing head HW for perpendicular recording is formed on the upper shield layer  16  of the reading head HR.  
      A first coil layer  18  that has a plurality of conductive parts  18   a  formed of a conductive material is formed on the upper shield layer  16  by a coil insulating base layer  17 . Each conductive part  18   a  of the first coil layer  18  is a single layer of one or more of non-magnetic materials selected from, for example, Au, Ag, Pt, Cu, Cr, Al, Ti, Nip, Mo, Pd, Rh, or a stacked layer of non-magnetic materials.  
      A conductive layer  30  is simultaneously formed of the same material as with the first coil layer  18  in a connecting hole  17  that is formed at a predetermined position in the height direction from the coil insulating base layer  17  on the upper shield layer  16 . A contact layer  31  is formed on the conductive layer  30 , for example, by nickel plating.  
      A first coil insulating layer  19  of an inorganic insulating material, for example, Al 2 O 3 , is formed over the first coil layer  18 , the conductive layer  30 , and the contact layer  31 . The first coil insulating layer  19  covers the first coil layer  18  and the upper surface  19   a  is planarized such that the upper surface of the contact layer  31  is exposed. A yoke  21 , a first magnetic part, is formed on the upper surface  19   a  of the first coil insulating layer  19  and extends from a position slightly closer to the recording medium-facing surface  10   a  than the first coil layer  18  in the height direction, and a main pole  20  is formed on the upper surface of the yoke  21 .  
      The main pole  20  is formed such that the width in the track width direction of the end exposed to the recording medium-facing surface  10   a  is the track width. The main pole  20  is tapered, but widening in the track width direction along the yoke  21  from the recording medium-facing surface  10   a  in the height (depth) direction. The main pole  20  and the yoke  21  are formed of a ferromagnetic material with high saturation magnetic flux density, for example, by plating. In the main pole  20 , a rectangular portion extending from the wide portion of the tapered portion is stacked on the yoke  21 . The main pole  20  and the yoke  21  form a first magnetic part.  
      The yoke  21  extends to the upper surface of the contact layer  31  in the height direction, of which the lower surface is connected with the upper surface of the contact layer  31 . The yoke  21  and the upper shield layer  16  are electrically connected with the same potential through the contact layer  31  and the conductive layer  30 .  
      An insulating material layer  22  surrounding the main pole  20  and the yoke  21  is provided on the upper surface  19   a  of the first coil insulating layer  19 . The upper surface  22   a  of the insulating material layer  22  forms the same surface as the upper surface  20   b  of the main pole  20 . The insulating material layer  22  may be formed of any one or more of, for example, alumina (Al 2 O 3 ), SiO 2 , Al—Si—O.  
      A gap layer  23  formed of an inorganic material, such as alumina or SiO 2 , on the main pole  20 , the yoke  21 , and the insulating material layer  22 .  
      A second coil layer  25  is formed on the gap layer  23  through the coil insulating base layer  23 . The second coil layer  25  is the same as the first coil layer  18  and includes a plurality of conductive parts  25   a  formed of a conductive non-magnetic metal. The second coil layer  25  is formed of one or more of non-magnetic metal selected from, for example, Au, Ag, Pt, Cu, Cr, Al, Ti, NiP, Mo, Pd, Rh, or may be formed by stacking non-magnetic metals. The insulating material layer  22 , gap layer  23 , and coil insulating base layer  24  are insulating layers.  
      In the conductive parts  18   a  and  25   a  of the first and second coil layers  18  and  25 , the ends in each track width direction (the X-axis direction) are electrically connected to form a solenoidal coil (not shown), so that a solenoidal coil is formed by winding the first and second coil layers  18  and  25  around the main pole  20  and the yoke  21 . As for the present embodiment, the width of the first coil layer  18  in the height direction (the Y-axis direction) is the same size as that of the second coil layer  25  in the height direction (the Y-axis direction).  
      In one embodiment, a second coil insulating layer  26  formed of an inorganic insulating material, for example, Al 2 O 3 , covers the second coil layer  25 . A return yoke  27 , a second magnetic part, is formed of a ferromagnetic material, such as permalloy, or the like, throughout the second coil insulating layer  26  and the gap layer  23 . The surface of the return yoke  27  that faces the recording medium is exposed to the recording medium-facing surface  10   a . The return yoke  27  is connected with a part of the main pole  20  that is not covered with the second coil insulating layer  26  through a conductive portion  27   b  located far from the recording medium-facing surface  10   a . According to the above configuration, a magnetic path from the main pole  20  through the return yoke  27  is formed.  
      A throat height determining layer  28  is formed of an inorganic or organic material at a predetermined distance from the recording medium-facing surface  10   a  in the height direction on the gap layer  23 . The throat height (gap depth) distance from the perpendicular recording magnetic head  10  is defined as from the recording medium-facing surface  10   a  to the front end of the throat height determining layer  28 .  
      On the coil insulating base layer  24 , a lead layer  29  that extends from the second coil layer  25  is formed at a predetermined position from the conductive portion  27   b  of the return yoke  27  in the height direction (the Y-axis). The return yoke  27  and the lead layer  29  are covered by a protecting layer  32  formed of, for example, an inorganic non-magnetic insulating material.  
      In a method of manufacturing the perpendicular recording magnetic head  10 , a process of manufacturing the conductive layer  30  and the contact layer  31  is described below with reference to FIGS.  2  to  7 .  FIGS. 2 and 3  are vertical cross-sectional views for different processes. As for FIGS.  4  to  7 , (a) shows a vertical cross-sectional view in each different process and (b) shows a front view that shows a portion above the upper shield layer  16  of the perpendicular recording magnetic head  10  in each different process.  
       FIG. 2  is a cross-sectional view that shows the upper shield layer  16  being formed. The coil insulating base layer  17  is formed on the upper shield layer  16  by spattering ( FIG. 1 ) such that it is wider than the region for the first coil layer  18 .  
      In one embodiment, each conductive part  18   a  of the first coil layer  18  and the conductive layer  30  are formed. The conductive part  18   a  and the conductive layer  30 , for example, are formed by a process of forming a plated base layer on the upper shield layer  16  under the region for the conductive part  18   a  and the connecting hole  17  for the conductive layer  30  and then forming non-magnetic material, for example, Cu, on the plated base layer with a predetermined thickness by electric plating ( FIGS. 4   a  and  4   b ).  
      Following the above process, the contact layers  18   b  and  31  are simultaneously formed with a predetermined thickness on the upper surface of both end of the conductive part  18   a  and the conductive layer  30  ( FIGS. 5   a  and  5   b ). The thicknesses of the first coil layer  18  and the conductive layer  30 , and the upper surface of the contact layer  1   b  are as high as the thickness of the coil insulating base layer  17  larger than the upper surface of the contact layer  31  ( FIG. 5   b ).  
      Subsequently, the first coil insulating layer  19  is formed by covering the first coil layer  18 , contact layer  18   b , conductive layer  30  and contact layer  31  with an inorganic insulating material such as Al 2 O 3  ( FIGS. 6   a  and  6   b ). After the covering, CMP process is applied to the first coil insulating layer  19  to planarize the upper surface. The upper surfaces of the contact layers  18   b  and  31  and the first coil insulating layer  19  are planarized such that they are level with each other through the CMP process ( FIG. 6   b ).  
      On the upper surface  19   a  of the first coil insulating layer  19 , the yoke  21  is formed of a ferromagnetic material that has high saturation magnetic flux density, for example, Ni—Fe, between the two rows of contact layers  18   b  spaced with a predetermined distance ( FIGS. 7   a  and  7   b ). The yoke  21  is formed from a predetermined position, which is closer to the recording medium-facing surface  10   a  than the first coil layer  18  in the height direction to a predetermined position such that it covers the upper surface of the contact layer  31 , more than the track width.  
      The upper shield layer  16  is electrically connected with the yoke  21  through the conductive layer  30  and the contact layer  31  by connecting the yoke  21  and the contact layer  31 , and both have the same potential.  
      The main pole  20  is formed on the upper surface of the yoke  21  and the other components are formed, but it is not described for avoiding repetition because they are formed through conventional processes. The main pole  20  may be connected with the contact layer  31  by changing places of the yoke  21  with the main pole  20  or removing the yoke  21 . The return yoke layer  27  (conductive part  27   b ) and the contact layer  31  may be connected.  
      The contact layer  28   c  may be stacked on the upper surface of the contact layer  18   b  while simultaneously forming the yoke  21  or the main pole  20  ( FIG. 7   b ). The contact layer  18   c  is connected with the end in the width direction of the conductive part  25   a  of the second coil layer  25  and a solenoidal coil is formed around the main pole  20  and the yoke  21 . In one embodiment, only the main pole  20  is included and not the yoke  21 .  
      In one embodiment, in the process of manufacturing the first coil layer  18 , the conductive layer  30  is formed of the ferromagnetic material as for the first coil layer  18  and the contact layer  31  is formed by nickel plating as the coil layer  18  in the process of manufacturing the contact layer  18   b.    
      In one embodiment, the reading element  14  and the main pole  20  maintain connection with the same potential without the processes or material being increased. The reading element  14  and the main pole  20  are connected by a non-magnetic material, so that the return yoke layer  27  and the upper shield layer  16  are magnetically connected and other shield, in addition to the main pole  20 , re-records recording signals onto a recording medium, thus the risk of loosing the signals is reduced.  
      Although the connecting hole is formed at the coil insulating base layer  17 , the length in the height direction of the coil insulating base layer  17  may shortened and the conductive layer  30  may be formed on the upper shield layer  16  exposed at a predetermined position from the coil insulating base layer  17 .  
      Various embodiments described herein can be used alone or in combination with one another. The forgoing detailed description has described only a few of the many possible implementations of the present invention. For this reason, this detailed description is intended by way of illustration, and not by way of limitation. It is only the following claims, including all equivalents that are intended to define the scope of this invention.