Patent Publication Number: US-2009231759-A1

Title: Head slider, head assembly and information storage device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The embodiments discussed herein are directed to a head slider, a head assembly, and an information storage device, and more particularly to a head slider including a read/write head, a head assembly including the head slider, and an information storage device including the head assembly. 
     2. Description of the Related Art 
     Magnetic storage devices, for example, hard disk drives (hereinafter referred to as “HDDs”) have been used in external magnetic storage devices of computers or consumer video storage devices, or the like. In recent years, users often handle information including large amounts of data (for example, moving images), and HDDs for storing the information require a large capacity, a high speed, low cost, and high reliability. 
     A magnetic head used in an HDD is held by a head slider, and while the head slider is kept lifted several tens nm above a magnetic disk medium, a read/write operation is performed by the magnetic head. In this case, a bit length of the magnetic disk medium can be shorter for a smaller flying height of the head slider (a narrower space between the head slider and the magnetic disk medium), and thus reducing the flying height is very effective for achieving higher density of the magnetic disk medium. 
     However, if foreign matter (contamination) in the HDD is caught between the head slider and the magnetic disk medium, a smaller space between the head slider and the magnetic disk medium, that is, a smaller flying height of the head slider may more frequently cause attitude changes of the head slider or damage to the magnetic disk medium or the magnetic head. This may reduce read/write performance of the HDD. 
     In this respect, recently proposed inventions relate to a shield plate intended for reducing an amount of dust entering a magnetic head (magnetic head core portion) (Japanese Patent Laid-open No. 55-129970) and a contact portion for protecting a magnetic head (magnetic transducer) from damage caused by foreign matter adhering to a disk medium (Japanese Patent Laid-open No. 8-279130). 
     However, a recent head slider is lifted in an inclined manner with respect to a magnetic disk medium surface, for example, as described in Japanese Patent Laid-open No. 2005-182883. In this case, an end from which air flows in (that is, an air inflow end) is further away from the magnetic disk medium surface than an end from which air flows out. Even if the shield plate (contact portion) described in the above-referenced patent documents is provided at the end from which air flows in, the shield plate (contact portion) has the same height as a surface (air bearing surface) facing a disk medium of the head slider. Thus, foreign matter (dust) entering between the head slider and the magnetic disk medium cannot be reduced. 
     Also, providing the shield plate (contact portion) on the head slider may affect a lift characteristic of the head slider. For example, when the shield plate (contact portion) is provided on the head slider to reduce a flying height of the head slider, the magnetic head and the magnetic disk medium may come into contact with each other and become damaged, causing read/write errors or the like. 
     Thus, a head slider, a head assembly, and an information storage device according to an embodiment of the present invention are achieved in view of the above described problems, and have an object to provide a head slider and a head assembly that prevent foreign matter (dust) from entering between the head slider and a disk medium, and obtain an appropriate flying height. 
     SUMMARY 
     In accordance with an aspect of embodiments, a head slider body includes a main body having a protruding air bearing surface, and a wall portion protruding from the air bearing surface near one end in one axial direction of the main body. A groove portion extending in the other axial direction is formed between the wall portion and the air bearing surface in the main body, and a read/write head is provided near the other end in the one axial direction of the head slider body. 
     Other features and advantages of embodiments of the invention are apparent from the detailed specification and, thus, are intended to fall within the scope of the appended claims. Further, because numerous modifications and changes will be apparent to those skilled in the art based on the description herein, it is not desired to limit the embodiments of the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents are included. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an internal configuration of an HDD according to an embodiment; 
         FIGS. 2A and 2B  are a perspective view and a vertical sectional view of an HGA in  FIG. 1 ; 
         FIG. 3  is a perspective view of a head slider; 
         FIGS. 4A and 4B  are a plan view and a side view of the head slider; 
         FIG. 5  shows a lift state of the head slider; 
         FIGS. 6A ,  6 B and  6 C illustrate a conventional head slider; 
         FIGS. 7A and 7B  are a table and a graph showing effectiveness of a dustproof rail provided on a head slider of the embodiment as compared with the conventional head slider; 
         FIGS. 8A ,  8 B and  8 C show a first variant of a dustproof rail; 
         FIGS. 9A ,  9 B,  9 C and  9 D illustrate an operation of the variant in  FIG. 8 ; 
         FIGS. 10A ,  10 B and  10 C show a second variant of a dustproof rail; 
         FIGS. 11A and 11B  show a third variant of a dustproof rail; and 
         FIGS. 12A and 12B  show a fourth variant of a dustproof rail. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Now, an embodiment of the present invention will be described in detail with reference to  FIGS. 1 to 7 . 
       FIG. 1  shows an internal configuration of a hard disk drive (HDD)  100  as an example of an information storage device according to an embodiment. As shown in  FIG. 1 , the HDD  100  includes a base  10 , three magnetic disks  12 A,  12 B and  12 C provided on the base  10 , a spindle motor  14 , and a head stack assembly (HSA)  20 , or the like. The base  10  actually constitutes a box-shaped casing together with an upper lid (top cover) provided to cover an upper surface of the base  10 , but in  FIG. 1 , the top cover is not shown for convenience in drawing. 
     The magnetic disks  12 A to  12 C have recording surfaces on front and back surfaces, and each magnetic disk is rotationally driven integrally around a rotating shaft by a spindle motor  14  at a high speed of, for example, 4200 to 15000 rpm. 
     The HSA  20  is connected rotatably around a support shaft  18 , and pivoted around the support shaft  18  by a voice coil motor  24 . The HSA  20  includes six head arms  26 , and six head gimbal assemblies (HGA)  30  mounted to tips of the head arms  26 . 
     The head arm  26  has a substantially isosceles triangular shape on plan view (viewed from above), and is formed by, for example, stamping a stainless sheet or extruding aluminum material. 
     The HGA  30  includes an elastic suspension  28 , and a head slider  16  provided at one end (an end on the side opposite from the support shaft  18 ) of the elastic suspension  28 . 
     Now, a detailed configuration of the HGA  30  will be described in detail with reference to  FIGS. 2A and 2B .  FIG. 2A  is a perspective view of an HGA  30  in an uppermost position among the six HGAs  30  in  FIG. 1  viewed from the side of the head slider  16  (back side), and  FIG. 2B  is a vertical sectional view of the HGA  30 . 
     As shown in the drawings, the elastic suspension  28  that constitutes the HGA  30  includes a spacer  34  secured to one end (an end on the side opposite from the support shaft  18 ) of the head arm  26 , a load beam  36  partly secured to the spacer  34 , and a reinforcing plate  38  secured to the load beam  36 . 
     The load beam  36  is made of, for example, stainless steel, and as shown in  FIG. 2A , a substantially U-shaped slit  42  is formed near one end thereof (an end on the side opposite from the end to which the spacer  34  is secured). Thus, the slit  42  is formed in the load beam  36  and thus a gimbal  40  is integrally formed in the load beam  36 . The gimbal  40  has a head slider holding surface  44  for holding the head slider  16  on one surface (an upper surface in  FIG. 2A  and a lower surface in  FIG. 2B ). In the load beam  36 , a portion between a portion to which the reinforcing plate  38  is secured and a portion to which the spacer  34  is secured is an elastically deformable spring portion  36   a.    
     The reinforcing plate  38  is made of, for example, stainless steel, and as shown in  FIG. 2B , a semispherical pivot  46  is provided in part on a surface (lower surface in  FIG. 2B ) facing the gimbal  40 . The pivot  46  abuts the gimbal  40  from above, and thus the gimbal  40  can be deformed around the pivot  46  in a vertical direction, a pitch direction, and a roll direction. Thus, the head slider  16  held by the gimbal  40  can be changed in attitude in the same direction. 
     Next, a configuration of the head slider  16  or the like will be described in detail with reference to  FIGS. 3 to 7 . 
       FIG. 3  is a perspective view of the head slider  16 ,  FIG. 4A  is a plan view of the head slider  16 , and  FIG. 4B  is a side view of the head slider  16 . As shown in the drawings, the head slider  16  includes a head slider body  50 , and a read/write head element  17  provided on the side of an air outflow end  50   b  of the head slider body  50 . The head slider body  50  may be made of, for example, Al 2 O 3 —TiC (AlTiC). 
     The read/write head element  17  includes, for example, a recording element that writes data in the magnetic disk  12 A using a magnetic field produced by a thin film coil pattern, and a reading element such as a giant magnetoresistance effect element (GMR) or a tunnel junction magnetoresistance effect element (TuMR) that reads data from the magnetic disk  12 A using resistance changes of a spin-valve film or a tunnel junction film. At the air outflow end  50   b  on which the read/write head element  17  is provided, an alumina film of several tens μm is formed so as to cover the read/write head element  17 . 
     The head slider body  50  has a complicated shape with a plurality of irregularities on an upper surface portion in  FIG. 3 . Surfaces having different heights that constitute the upper surface portion are positioned, as shown in  FIG. 4B , at “+2 level”, “+1 level”, “0 (reference) level”, and “−1 level” in order from higher to lower. In the embodiment, for example, a dimension between the +2 level and the +1 level is 50 nm, a dimension between the +1 level and the 0 level is 0.2 μm, and a dimension between the +1 level and the −1 level is 2 μm. In  FIGS. 3 and 4B , or the like, the dimensions are not necessarily as mentioned above for convenience in drawing and description. 
     More specifically, as shown in  FIG. 3 , the head slider body  50  includes a front rail  52  placed on the side of an air inflow end  50   a , a rear center rail  54  and rear side rails  56   a  and  56   b  placed on the side closer to the air outflow end  50   b  than the front rail  52 , and a dustproof rail  58  placed on the side closer to the air inflow end  50   a  than the front rail  52 . The rails are formed by milling a rectangular parallelepiped member (a member finally forming the head slider body  50 ) originally having a height of the +2 level or higher by an exposure technique using a photo mask or a resist. On a surface of each rail, a protective film of, for example, DLC (diamond like carbon) is formed. 
     The front rail  52  has an air bearing surface  62  as a air bearing surface extending in a width direction of the head slider body  50  at the +1 level, and step surfaces ( 64   a ,  64   b ,  66   a ,  66   b ,  68   a  and  68   b ) at the 0 (reference) level. More specifically, the step surfaces include a pair of front step surfaces  64   a  and  64   b  on the side of the air inflow end  50   a  of the air bearing surface  62 , and a pair of side step surfaces  66   a  and  66   b  and a pair of center step surfaces  68   a  and  68   b  on the side of the air outflow end  50   b  of the air bearing surface  62 . 
     The rear center rail  54  is provided substantially at the center in the width direction of the head slider body  50  on the side closer to the air outflow end  50   b  than the front rail  52 , and includes an air bearing surface  72  as an air bearing surface at the +1 level, and a step surface  74  at the 0 (reference) level. 
     The rear side rails  56   a  and  56   b  are provided near opposite ends in the width direction of the head slider body  50  on the side closer to the air outflow end  50   b  than the front rail  52 . One rear side rail  56   a  has an air bearing surface  76   a  as a air bearing surface at the +1 level, and a step surface  78   a  at the 0 level. The other rear side rail  56   b  has an air bearing surface  76   b  as a air bearing surface at the +1 level and a step surface  78   b  at the 0 level. 
     The dustproof rail  58  has a substantially rectangular shape, and is provided over the entire width of the head slider body  50  at the air inflow end  50   a  of the head slider body  50  so as to have the height of the +2 level. 
     Portions other than the front rail  52 , the rear center rail  54 , the rear side rails  56   a  and  56   b , and the dustproof rail  58  all have the height of the −1 level. More specifically, on the side closer to the air outflow end  50   b  than the front rail  52 , a portion other than the rear center rail  54  and the rear side rails  56   a  and  56   b  is a recess  82  having a relatively large area. Also, a pair of groove portions  70   a  and  70   b  extend in the width direction of the head slider body  50  between the dustproof rail  58  and the front rail  52 . 
     The head slider body  50  thus configured has, in other words, a structure including a main body (a portion other than the dustproof rail  58 ) having protruding air bearing surfaces (air bearing surfaces ( 62 ,  72 ,  76   a  and  76   b )), and the dustproof rail  58  protruding from the air bearing surfaces (air bearing surfaces ( 62 ,  72 ,  76   a  and  76   b )) near the air inflow end  50   a  and extending in the width direction, and the groove portions  70   a  and  70   b  extending in the width direction are formed between the dustproof rail  58  and the air bearing surfaces (air bearing surfaces ( 62 ,  72 ,  76   a ,  76   b )). 
     Next, the principle of lifting of the head slider  16  above the magnetic disk  12 A will be described with reference to  FIGS. 4 and 5 . 
     While the magnetic disk  12 A is rotationally driven by the spindle motor  14  in a predetermined rotational direction (the direction of black arrow X 1  in  FIG. 5 ), the head slider  16  is positioned above the magnetic disk  12 A by the voice coil motor  24 . Then, an air flow generated on a surface of the magnetic disk  12 A by rotation of the magnetic disk  12 A enters between the dustproof rail  58  and the magnetic disk  12 A, and part of an air flow colliding with the dustproof rail  58  flows around the dustproof rail  58  and enters the groove portions  70   a  and  70   b  as shown by dotted arrow AR 1  in  FIG. 4A . The air entering the groove portions  70   a  and  70   b  and the air entering between the dustproof rail  58  and the magnetic disk  12 A collides with steps between the front step surfaces  64   a  and  64   b  and the air bearing surface  62  of the front rail  52  as shown by dotted arrow AR 2  in  FIG. 4A , and the air is compressed by the collision (pressure is increased). 
     Then, when the compressed air moves to between the air bearing surface  62  and the magnetic disk  12 A as shown by dotted arrow AR 3  in  FIG. 4A , the compressed air applies pressure between the air bearing surface  62  and the magnetic disk  12 A to produce buoyancy as shown by open arrow F 1  in  FIG. 5 . 
     Then, the compressed air that has applied pressure between the air bearing surface  62  and the magnetic disk  12 A moves from the front rail  52  toward the recess  82  as shown by dotted arrow AR 4  in  FIG. 4A . The air having flown into the recess  82  expands in the recess  82  to generate negative pressure. The negative pressure generates a force directed from the head slider  16  to the magnetic disk  12 A as shown by open allow F 2  in  FIG. 5 . 
     Further, also in the rear center rail  54  and the rear side rails  56   a  and  56   b , as shown by dotted arrow AR 5  in  FIG. 4A , when air collides with steps between the step surfaces  74 ,  78   a  and  78   b  and the air bearing surfaces  72 ,  76   a  and  76   b , the air is compressed, and the compressed air applies pressure between the air bearing surfaces  72 ,  76   a  and  76   b  and the magnetic disk  12 A to produce buoyancy as shown by open arrow F 3  in  FIG. 5 . 
     A pressing force from the elastic suspension  28  toward the surface of the magnetic disk  12 A is applied to the head slider  16 , and thus a balance between the pressing force and the buoyancy (F 1  and F 3 ) and the force by the negative pressure (F 2 ) applied to the head slider  16  causes the head slider  16  to be kept lifted above the magnetic disk  12 A with relatively high rigidity during rotation of the magnetic disk  12 A. 
     In this case, the air bearing surface  62  that constitutes the front rail  52  has a larger area than the total area of the air bearing surfaces  72 ,  76   a  and  76   b  of the rear center rail  54  and the rear side rails  56   a  and  56   b , and thus the buoyancy (F 1  in  FIG. 5 ) generated on the front rail  52  is higher than the buoyancy (F 3  in  FIG. 5 ) generated on the rear center rail  54  and the rear side rails  56   a  and  56   b . Thus, the head slider  16  of the embodiment is lifted so that the air inflow end  50   a  is higher than the air outflow end  50   b  with respect to the magnetic disk  12 A as shown in  FIG. 5 . An inclination angle (pitch angle) of the head slider  16  in this case is, for example, 200 μrad. 
     In the embodiment, as described above, the head slider  16  is lifted in an inclined manner (so that the air inflow end  50   a  is higher than the air outflow end  50   b ), and dust easily enters between the head slider  16  and the magnetic disk  12 A. Thus, in the embodiment, to minimize entering of dust, the dustproof rail  58  provided at the air inflow end  50   a  of the head slider body  50  protrudes from the air bearing surfaces ( 62 ,  76   a ,  76   b  and  72 ). Now, an experiment for checking the effect of the dustproof rail  58  will be briefly described. 
       FIG. 6A  is a plan view of a conventional head slider  116  (a head slider without a dustproof rail), and  FIG. 6B  is a sectional view taken along the line A-A in  FIG. 6A . As shown in  FIG. 6C , the conventional head slider is also lifted above a magnetic disk  12 A so that an air inflow end  50   a  is higher than an air outflow end  50   b  like the head slider  16  of the embodiment. 
     The inventor lifted the conventional head slider  116  and the head slider  16  of the embodiment above a magnetic disk  12 A intentionally contaminated (a magnetic disk  12 A to which large amounts of dust adhere), and analyzed how much dust adheres to a particular portion on each of the head sliders  116  and  16  while the magnetic disk  12 A rotates for a predetermined time (or for a predetermined number of turns). The particular portion is a portion near the air inflow end (reference character W in  FIG. 6C ) for the conventional head slider  116 , and a portion near a lower end (reference character V in  FIG. 5 ) of the dustproof rail  58  for the head slider  16  of the embodiment. In this case, the inventor performed the analysis by observing a predetermined range such as one shot (for example, a width of 70 μm) with an SEM (Scanning Electron Microscope), and counting the number of dust particles adhering to the range for each size (diameter) of the dust particles.  FIGS. 7A and 7B  are a table and a graph showing the analysis result. 
     The analysis result ( FIGS. 7A and 7B ) reveals that the amount of dust captured at the dustproof rail  58  in the embodiment is much larger than the amount of dust captured at the air inflow end of the conventional head slider  116  (about six times in total). Specifically, from this result, it can be supposed that the dustproof rail  58  newly provided in the embodiment can effectively capture dust that cannot be captured by the conventional head slider  116 , and thus the amount of dust entering between the head slider  16  and the magnetic disk  12 A can be reduced as compared with the conventional head slider. 
     The counting method of the number of dust particles is not limited to the above, but the number of dust particles may be counted over the entire particular portion on each head slider, or a plurality of shots may be observed with the SEM to calculate a statistical calculation result such as an average value of the results. Also, the number of dust particles (the amount of dust) may be counted (calculated) by weighting calculation in view of the size of the dust particle. 
     In the embodiment, as described above, the dustproof rail  58  can be provided to reduce the amount of dust entering between the head slider  16  and the magnetic disk  12 A as compared with the conventional example. Also, the groove portions  70   a  and  70   b  are provided, and thus even if a flow of air to be supplied from the air inflow end to the air bearing surface  62  or the like is blocked by the dustproof rail  58 , air flowing around the dustproof rail  58  is efficiently supplied to the air bearing surface  62  or the like through the groove portions  70   a  and  70   b  formed near the dustproof rail  58  (see dotted arrows AR 1 , AR 2  and AR 3  in  FIG. 4A ), and the dustproof rail  58  can be provided without any trouble, allowing the flying height of the head slider  16  to be appropriately maintained. 
     Returning to  FIG. 1 , other HGAs  30  (HGAs in second to sixth positions from the top) that constitute the HSA  20  have the same configuration as described above. Thus, the descriptions of the other HGAs will be omitted. 
     As described above in detail, according to the embodiment, the head slider  16  includes the dustproof rail  58 , and the dustproof rail  58  prevents dust from entering between the head slider  16  and the magnetic disk  12 A. This can prevent damage to the magnetic disk  12 A or the read/write head element  17  and read/write errors due to dust being caught between the head slider  16  and the magnetic disk  12 A. In the embodiment, the dustproof rail  58  is provided, and thus even if the flow of air to be supplied to the air bearing surface  62  or the like is blocked, air flowing around the dustproof rail  58  is efficiently supplied to the air bearing surface  62  and the like through the groove portions  70   a  and  70   b  formed near the dustproof rail  58 , allowing the flying height of the head slider  16  to be appropriately maintained. The HDD  100  of the embodiment includes the head slider  16  (or the HGA  30 ) that can maintain the appropriate flying height, and thus can achieve read/write with high accuracy and high recording density. 
     In the embodiment, the portion of the head slider  16  facing the magnetic disk is constituted by a combination of four types of surfaces having different heights, and thus the head slider  16  can be formed only by milling a wafer or the like (without polishing or the like). 
     In the embodiment, the case of adopting the dustproof rail  58  having a substantially rectangular shape has been described, but is not limited to this as a dustproof rail having a different shape may be adopted. 
     Specifically, for example, as shown in  FIGS. 8A to 8C , dustproof rails ( 158 ,  258  and  358 ) having different heights at an end on the side of the air inflow end and at an end on the side of the air outflow end (the latter is lower) may be adopted. In this case, for example, as the dustproof rail  158  in  FIG. 8A , the height may be changed stepwise from the end on the side of the air inflow end toward the end on the side of the air outflow end. Specifically, an end surface (an upper surface in  FIG. 8A ) on a protruding side of the dustproof rail  158  may be formed closer to the air bearing surface  62  or the like stepwise from the end on the side of the air inflow end toward the end on the side of the air outflow end. The embodiment is not limited to the case where the height is changed in only one step as shown in  FIG. 8A , but the height may be changed in two or more steps. 
     As the dustproof rail  258  in  FIG. 8B , the height may be changed linearly (continuously) from the end on the side of the air inflow end toward the end on the side of the air outflow end, or as the dustproof rail  358  in  FIG. 8C , the height may be changed roundedly (continuously) from the end on the side of the air inflow end toward the end on the side of the air outflow end. Specifically, as the dustproof rails ( 258  and  358 ), end surfaces (upper surfaces in  FIGS. 8B and 8C ) on a protruding side may be formed closer to the air bearing surface  62  or the like linearly or roundedly from the end on the side of the air inflow end toward the end on the side of the air outflow end. The dustproof rails  258  and  358  can be produced (formed), for example, by forming a dustproof rail having a flat plate shape (rectangular shape) as the dustproof rail  58  in the embodiment on the head slider, then lifting the head slider above a polishing medium rotating at a predetermined rotation speed, and bringing the dustproof rail into contact with the polishing medium at an appropriate angle (pitch angle) with an appropriate pressing force. 
     In any of  FIGS. 8A to 8C , as shown in  FIGS. 9A to 9C , when the head slider  16  is lifted above the magnetic disk  12 A, the end on the side of the air outflow end cannot be lower than the end on the side of the air inflow end (in  FIG. 9A , near the end). This can maintain the dustproof effect by the dustproof rail, and ensure an adequate flying height between the head slider and the magnetic disk. 
     In place of  FIG. 9B , as shown in  FIG. 9D , a dustproof rail  258 ′ may be adopted having a lower end that becomes parallel to the magnetic disk surface when the head slider  16  is lifted above the magnetic disk. In this case, an angle at the lower end of the dustproof rail  258 ′ may be the same as the inclination angle (for example, 200 μrad) of the head slider  16 . Thus, even if the rotation of the magnetic disk  12 A suddenly stops to bring the surface of the magnetic disk  12 A into contact with the dustproof rail  258 , a contact area between the dustproof rail  258  and the magnetic disk  12 A can be larger than in  FIG. 9B  or the like. This can prevent damage to the surface of the magnetic disk  12 A. 
     In the embodiment, the dustproof rail  58  having a uniform height in the width direction of the head slider  16  is adopted, but is not limited to this, for example, as shown in  FIGS. 10A to 10C , dustproof rails ( 458 ,  558  and  658 ) may be adopted having different heights at a central position in the width direction and at opposite ends in the width direction (the opposite ends are lower). For example, as the dustproof rail  458  in  FIG. 10A , the height may be reduced stepwise from the central portion in the width direction toward the opposite ends in the width direction of the head slider  16 . Specifically, an end surface (upper surface in  FIG. 9A ) on a protruding side of the dustproof rail  458  may be formed closer to the air bearing surface  62  or the like stepwise from the central portion in the width direction toward the opposite ends in the width direction. In  FIG. 10A , the height is reduced in two steps, but is not limited to this. The height may be reduced in one step or multiple steps. Also, as the dustproof rail  558  in  FIG. 10B , the height may be reduced linearly (continuously) from the central portion in the width direction toward the opposite ends in the width direction of the head slider  16 , or as the dustproof rail  658  in  FIG. 10C , the height may be reduced roundedly (continuously) from the central portion in the width direction toward the opposite ends in the width direction of the head slider  16 . Specifically, as the dustproof rails ( 558  and  658 ), end surfaces (upper surfaces in  FIGS. 9B and 9C ) on a protruding side may be formed closer to the air bearing surface  62  or the like continuously (linearly or roundedly) from the central portion in the width direction toward the opposite ends in the width direction. In any case, even if the head slider  16  rolls to some extent (performs a rotation operation in an air inflow direction), contact between each of the dustproof rails  458 ,  558  and  658  and the surface of the magnetic disk  12 A can be prevented. In view of capturing efficiency of dust, the height of the opposite ends in the width direction of each of the dustproof rails  458 ,  558  and  658  is desirably the +1 level or higher in  FIG. 4B . 
     The dustproof rail  558  can be produced (formed), for example, by forming a dustproof rail having a flat plate shape (rectangular shape) as the dustproof rail  58  in the embodiment on the head slider, then lifting the head slider above a polishing medium rotating at a predetermined rotation speed, and bringing corners of the dustproof rail into contact with the polishing medium at an appropriate angle (a rolling angle) with an appropriate pressing force. The dustproof rail  658  can be produced (formed), for example, by forming a dustproof rail having a flat plate shape (rectangular shape) on the head slider, then lifting the head slider above a polishing medium rotating at a predetermined rotation speed, and bringing the dustproof rail into contact with the polishing medium and causing the dustproof rail to reciprocate a predetermined number of times within a predetermined angle (the rolling angle). 
     The concept of the variant in  FIGS. 8A to 8C  (or  FIGS. 9A to 9D ) and the concept of the variant in  FIGS. 10A to 10C  may be combined. For example, as a dustproof rail  758  in  FIG. 11A , the height may be changed linearly (continuously) from the end on the side of the air inflow end toward the end on the side of the air outflow end, and the height may be changed linearly (continuously) from the central portion toward the opposite ends in the width direction, or for example, as a dustproof rail  858  in  FIG. 11B , the height may be changed roundedly (continuously) from the end on the side of the air inflow end toward the end on the side of the air outflow end, and the height may be changed roundedly (continuously) from the central portion toward the opposite ends in the width direction. Thus, the advantages of both the variants can be simultaneously achieved. The embodiments are not limited to the combinations in  FIGS. 11A and 11B , as a dustproof rail with a combination of any of  FIGS. 8A to 8C  and any of  FIGS. 10A to 10C  may be adopted. In any case, the same advantage as the combinations in  FIGS. 11A and 11B  can be achieved. 
     In the embodiment, as shown in  FIG. 3 , the case where the dustproof rail  58  is provided (formed) over the entire width of the head slider  16  has been described, but is not limited to this. For example, when a method of collectively forming a plurality of head sliders in one member (one wafer) and finally cutting the member into a plurality of thin head sliders is adopted in production of a head slider (head slider body), the opposite ends in the width direction of the dustproof rail  58  may be positioned slightly inwardly of the opposite ends in the width direction of the head slider body  50  for ensuring cutting margins (for preventing deformation of or damage to the dustproof rail caused by the cutting). 
     In the embodiment, the HSA  20  pivots around the rotating shaft of the support shaft  18 , and thus as shown in  FIG. 12A , the head slider  16  arcuately moves (seeks) around a rotation shaft  0  above the magnetic disk  12 A. Thus, the dustproof rail may be provided in a range where the air flow AR (that is, dust flowing with the air flow AR) can be prevented from coming into contact with the read/write head element  17  when the head slider  16  is positioned on the innermost side of the magnetic disk  12 A (denoted by reference character  16 ′ in  FIG. 12A ), and the air flow (dust) can be prevented from coming into contact with the read/write head element  17  when the head slider  16  is positioned on the outermost side of the magnetic disk  12 A (denoted by reference character  16 ″ in  FIG. 12A ). Specifically, as a dustproof rail  958  in  FIG. 12B , the dustproof rail may have a width including a maximum yaw angle α (an angle between a line In and a line Out) in a seek. Thus, the advantage as in the above described embodiment can be achieved, and the width of the dustproof rail can be minimized, thereby reducing the weight of the head slider. 
     The above described embodiment is a preferred embodiment of the present invention. But not limited to this, various modifications may be made without departing from the gist of the present invention.