Abstract:
A head slider has a chamfered pad between the side edge and rail at the surface opposing the disk. The pad prevents contact between the edge of the basic material of the head slider and the disk. Contact between the pad and disk can be generated, but since the pad is chamfered, the disk is not as easily damaged. In comparison with chamfering the basic material and rail, the present invention has less influence on the floating characteristics of the slider, so the amount of chamfering can be increased. Therefore, damage to the disk can be alleviated remarkably and shock resistance of disk apparatus can be much improved.

Description:
The present invention relates to a structure of a head for writing or reading data to or from a disk medium, and more particularly, to a structure of a floating type head for stopping in contact on the disk medium during the non-operating condition and recording or reading data to or from the disk medium while it is floating thereon during the recording/reproducing operation. 
     BACKGROUND OF THE INVENTION 
     In disk apparatus for recording or reproducing information to or from a disk medium, a contactstartstop system (CSS system) is often employed, in which the head slider is in contact with the disk surface during the non-operating condition, and floats over the surface of the disk when it rotates during the recording and reproducing operation, in order to avoid wear due to contact between the head slider on which a head element is loaded and the disk surface. 
     FIG. 1 shows a head slider of the related art. FIG.  1 ( a ) is a plan view of the surface of the head slider opposing the disk, and FIG.  1 ( b ) shows an end surface of the air outgoing side of the head slider. 
     At a surface  1   a  opposing a disk  50 , a couple of projected stripe type rails  3  are formed in basic material  11  of a head slider  90 . At an air bearing surface  3   a  of the rail  3 , an adsorption preventing pad  5  is formed to prevent adsorption or touching of the air bearing surface  3   a  of rail  3  to the surface of disk  50 . At the air incoming end side of the air bearing surface  3   a , a tapered portion  6  is formed to easily generate a floating force for the head slider  90 . At the end surface of the air outgoing side of the head slider  90 , an electromagnetic transducer  2  such as an inductive head, magneto-resistive element and/or spin bulb magneto-resistive element is formed. 
     In disk devices using a CSS system, the head slider  90  is supported by a suspension (not illustrated) having a spring. When the disk  50  is rotating, the head slider  90  floats by receiving the air flow generated by rotation of the disk  50  at its disk confronting surface, and is in contact with the CSS zone  50   a  of the disk  50  (FIG.  1 ( b )) when the disk  50  is not rotated. During the reading or writing operation, the head slider  90  moves across the surface of the rotating magnetic disk  50  while it is floating therefrom, and the head element  2  mounted to the head slider  90  reads and writes information from and to the predetermined tracks of the disk  50 . 
     In recent years, with further reduction in the size of magnetic disk devices, such disk devices have been introduced into portable apparatus such as a note-size personal computer as memory. However, the magnetic disk devices are exposed to external shock. Therefore, high durability and shock resistance are required for such magnetic disk apparatus. 
     In magnetic disk devices using the CSS system, the head slider is in contact with the CSS zone at the surface of the magnetic disk while the disk is not rotated. In this condition, when the magnetic disk apparatus receives shock during transportation or by dropping, the head slider is tilted and an edge  7  of the basic material  111  illustrated in FIG.  1 ( a ) slides on the surface of the magnetic disk  50 . The edge of the head slider is hard and sharp. Therefore, when the edge  7  slides on the surface of the magnetic disk  50 , the disk  50  can become damaged, generating the phenomenon that data is destroyed or data reading or writing is disabled. Thereby, shock resistance of the magnetic disk apparatus is lowered. As a structure for alleviating wear of the magnetic disk and head slider, the edge of the basic material of the head slider could be chamfered. However, this method is not so effective because the amount of chamfering cannot be increased. Moreover, the width of the floating rail up to the side edge of the head slider could be widened in order to chamfer the edge of the rail, but when the width of the floating rail is widened, the floating characteristic changes and the desired floating height cannot be attained. 
     OBJECTS OF THE INVENTION 
     Accordingly, one object of the present invention is to enhance the shock resistance of magnetic disk devices. 
     Another object of the present invention is to provide a head slider which can alleviate wear caused by the disk. 
     Moreover, a further object of the present invention is to provide a head slider which has good floating characteristics. 
     SUMMARY OF THE INVENTION 
     The head slider of the present invention has a chamfered pad between the side edge and rail at the surface opposing the disk. In this manner, the pad avoids contact between the edge of the basic material of the head slider and the disk. Contact between the pad and disk can occur, but since the pad is chamfered, the disk is not easily damaged. In comparison with chamfering the basic material and rail, the present invention has less influence on the floating characteristics of the slider, so the amount of chamfering can be increased. Therefore, damage to the disk can be alleviated remarkably and shock resistance of disk apparatus can be much improved. 
     Moreover, the head slider of the present invention can have a pad formed with a height lower than the height of the slider rail at the side edge at the surface opposing the disk. According to this structure, not only the contact between the edge of the basic material of the head slider and the disk medium can be avoided, but also the pad does not regulate the floating height of the head slider. In this manner, the shock resistance of disk apparatus can be improved, without increasing the floating height of the head slider and thereby high recording density of the disk apparatus can be realized. 
     Here, it is desirable that the hardness of the pad be lower than the hardness of the basic material. According to this structure, contact between the pad and disk medium is generated but since hardness of the pad is lowered, the disk is not damaged as easily. Therefore, damage to the disk is alleviated and shock resistance can further be improved. 
     Moreover, the height of the pad can be made equal to the height of the slider rail, and the pad and slider rail can be formed of the same material. According to this structure, the pad and slider rail can be formed by the same process. Accordingly, manufacturing cost can be reduced through reduction of manufacturing processes. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above mentioned and other features of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which: 
     FIG.  1 ( a ) is a plan view of a conventional head slider; 
     FIG.  1 ( b ) shows an end surface of the air outgoing side of the conventional head slider of FIG.  1 ( a ); 
     FIG. 2 is a plan view of a magnetic disk apparatus of the present invention; 
     FIG. 3 is a cross-sectional view of the magnetic disk apparatus of FIG. 2, taken along the line A—A of FIG. 2; 
     FIG.  4 ( a ) is a plan view of the head slider of the first embodiment of the present invention; 
     FIG.  4 ( b ) is a side view of the head slider of the first embodiment of the present invention; 
     FIG.  4 ( c ) shows an end surface of the air outgoing side of the first embodiment of the present invention; 
     FIG.  5 ( a ) shows the wafer on which a plurality of transducers is formed; 
     FIG.  5 ( b ) shows a slider bar cut out from the wafer; 
     FIG.  5 ( c ) shows the rod type body fixed in a holder; 
     FIGS.  6 ( a )- 6 ( h ) show the manufacturing process of the head slider of the first embodiment of the present invention; 
     FIG.  7 ( a ) is a plan view of the rod type body in the condition shown in FIG.  6 ( c ); 
     FIG.  7 ( b ) is a plan view of the rod type body in the condition shown in FIG.  6 ( f ); 
     FIG.  7 ( c ) is a plan view of the rod type body on which a resist pattern is formed in the second embodiment of the present invention; 
     FIG. 8 shows a polishing apparatus; 
     FIG.  9 ( a ) is cross-sectional view of a surface plate having a conic shaped polishing surface; 
     FIG.  9 ( b ) is a cross-sectional view of a surface plate having a curved polishing surface; 
     FIG.  9 ( c ) is cross-sectional view of a surface plate having a conic shaped polishing surface in which the radius of curvature is different in the inner circumference and outer circumference; 
     FIG.  9 ( d ) is a cross-sectional view of a surface plate having a curved polishing surface in of which the radius of curvature is different in the inner circumference and outer circumference; 
     FIG.  10 ( a ) shows rod type bodies arranged on the surface of the weight; 
     FIG.  10 ( b ) shows the rotating surface plate and weight; 
     FIG.  11 ( a ) is a plan view of the head slider of the second embodiment of the present invention; 
     FIG.  11 ( b ) is a side view of the head slider of the second embodiment of the present invention; 
     FIG.  11 ( c ) shows an end surface of the air outgoing side of the head slider of the second embodiment of the present invention; 
     FIGS.  12 ( a )- 12 ( i ) show steps in the manufacturing process of the head slider of the three-stage structure; and 
     FIGS.  13 ( a )- 13 ( e ) show steps in the manufacturing process of the head slider including the rail and buffer pad consisting of different materials. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG.  2  and FIG. 3 illustrate a magnetic disk in the preferred embodiment of the present invention. A magnetic disk  50  is driven by a spindle motor  52  provided on a base plate  51 . In this embodiment, three magnetic disks are used. 
     An actuator  53  to support and drive the head slider is supported to rotate on the base plate  51 . At one end of the actuator  53 , a plurality of head arms  54  extending in the direction parallel to the recording surface of the magnetic disk  50  are formed. At one end of the head arm  54 , a suspension  55  is mounted. A head slider  1  is mounted to a flexure of the suspension  55  by insulating film (not illustrated). At the other end of actuator  53 , a coil  57  is mounted. 
     On the base plate  51 , a magnetic circuit  58 , formed of a permanent magnet and a yoke, is provided and the coil  57  is arranged within the magnetic gap of the magnetic circuit  58 . With the magnetic coil  58  and coil  57 , a voice coil motor (VCM) is formed. Moreover, the upper part of the base plate  51  is covered with a cover  59 . 
     Operations of the magnetic disk apparatus will then be explained. When the magnetic disk  50  is not rotated, the head slider  1  stops in contact with a save zone (CSS zone)  50   a  of the magnetic disk  50 . The position of the CSS zone  50 a is not limited to the internal circumference of the disk  50  and may be located at the external circumference thereof. Next, when the magnetic disk  50  is rotated by the spindle motor  52 , the head slider floats on the disk, keeping only a small distance therefrom due to the air flow generated by rotation of the magnetic disk  50 . When a current flows into the coil  57  and the head slider is floating, a propulsive force is generated by the coil  57  to rotate the actuator  53 . The head slider moves to a predetermined track of the magnetic disk  50  in order to perform the data reading or writing. 
     FIG. 4 shows the head slider of the first embodiment mounted to the magnetic disk apparatus explained above. FIG.  4 ( a ) shows the surface of the head slider opposing the disk, FIG.  4 ( b ) shows the side surface, and FIG.  4 ( c ) shows the end surface in the air outgoing side. 
     A base material  11  of the head slider in the first embodiment of the present invention is formed of a material such as aluminum titanium carbide (Al 2 O 3 TiC), ferrite or calcium titanate. The head slider has a length L of 0.6 to 1.3 mm, width W of 0.5 to 1.0 mm and height H of 0.1 to 0.4 mm. The head slider  1  is mounted on the magnetic disk apparatus to float from the surface of the rotating magnetic disk  50 . 
     At a surface  1   a  of the basic material  11 , a couple of stripe type rails  3  are projected to generate the predetermined floating force to the head slider  1 . Height h of the rails  3  from the opposing surface  1   a  is preferably 30 μm or less and their width w is 0.5 mm or less. 
     At an air bearing surface  3   a  of the rails  3 , an adsorption preventing pad  5  is formed. The adsorption preventing pad  5  reduces the contact area of the head slider  1  with the magnetic disk  50  and prevents contact of the air bearing surface  3   a  with the magnetic disk  50 . A tapered portion  6  is formed at the air incoming end side of the air bearing surface  3   a  and this tapered portion  6  easily generates a floating force by the air flow. 
     At the end surface in the air outgoing side of the head slider  1 , an electromagnetic transducer  2  (such as an inductive head, a magneto-resistive element and a spin valve magneto-resistive element) is formed. 
     At each corner of the basic material  11 , a buffer pad  4  is formed. The surface of buffer pad  4  is chamfered in a certain radius and processed as a smoothly curving surface. Adequate radius r of the cross-section of the buffer pad is ranged from 0.3 to 0.5 mm. Height of the buffer pad  4  from the opposing surface  1   a  is equal to the height of the rails  3 . 
     In the magnetic disk apparatus employing the contactstartstop system, when rotation of the magnetic disk  50  stops, the head slider  1  is in contact with the CSS zone of the magnetic disk  50 . In general, a lubricating film having viscosity is formed as the upper most layer of the magnetic disk  50 . When the contact area of the lubricating film and the head slider is wide, the head slider is attracted by the surface tension of the lubricating film and is adsorbed to the disk medium. Under this condition, a load of the spindle motor  52  to rotate the magnetic disk  50  becomes large and suspension  55  supporting the head slider deforms. However, in the head slider  1  of the present invention, an adsorption preventing pad  5  is formed at the air bearing surface  3   a.  As a result, the contact area with the magnetic disk  50  is reduced, and adsorption to the magnetic disk  50  of the head slider  1  is prevented. 
     Moreover, in the magnetic disk apparatus employing the contactstartstop system, if it receives a shock when rotation of the magnetic disk stops, the head slider and magnetic disk surface contact each other. However, in the head slider  1  of the present invention, the buffer pad  4  is formed at the corner of the basic material  11  and the buffer pad  4  is in contact with the magnetic disk  50 . Since the buffer pad  4  is covered at the surface with a curving surface as explained above, if the buffer pad  4  is in contact with the magnetic disk  50 , wear of the magnetic disk  50  is eased. Although four buffer pads  4  are formed on the opposing surface  1   a , it is enough when at least one buffer pad  4  exists. 
     The manufacturing process of the head slider  1  illustrated in FIG. 4 will be explained below. 
     First, as illustrated in FIG.  5 ( a ), a plurality of electromagnetic conversion elements  2  are formed in two dimensions on the main surface of the wafer (basic material)  11  consisting of the materials such as aluminum titanium carbide (Al 2 O 3 TiC), ferrite or calcium titanate or the like. The electro-magnetic conversion element  2  is composed of a magneto-resistive element and an inductance element, etc. which are respectively connected to a couple of terminals. predetermined shape through the processes explained later. 
     Next, the wafer  11  is divided by cutting it along the parallel broken lines of FIG.  5 ( a ) with a dicing saw. With the dividing process, a plurality of rod type bodies  12  in which electro-magnetic conversion elements  2  are arranged in a line can be obtained, as illustrated in FIG.  5 ( b ). Since the rod type bodies  12  are eventually divided into a plurality of bodies to become magnetic head sliders, the tapered portion  6  (FIG.  4 ( a )) is formed to the area which becomes the air incoming end of the air bearing surface  3   a  (FIG.  5 ( c )). The surface of the magnetic pole of the electro-magnetic conversion element  2  of the rod type body  12  becomes the disk confronting surface of the slider explained above. 
     Subsequently, as illustrated in FIG.  5 ( c ), a plurality of rod type bodies  12  are fixed to a holder  14 . The rod type bodies  12  are fixed to the holder  14  with the air bearing surface  3   a  placed upward and the cutting surfaces provided opposed with each other. The inside of the holder  4  has a structure to regulate free movement of the rod type body  12 . The rode type body  12  fixed to the holder  14  is processed to the predetermined shape through the processes explained later. 
     FIGS.  6 ( a ) to  6 ( h ) illustrate the cutting surface of the rod type body  12 . Using FIG. 6, the machining processes of the rod type body  12  in the first embodiment will be explained. 
     In FIG.  6 ( a ), a SiC film  25  is formed in the thickness of 5 nm on the basic material  11  of rod type body  12 , a first DLC film  26  consisting of diamond like carbon (DLC) is formed in the thickness of 30 nm on the SiC film  25 , a SiC film  27  is formed in the thickness of 3 nm on the first DLC film  26  and a second DLC film  28  consisting of DLC is formed in the thickness of 30 nm on the SiC film  27 . 
     The SiC film  25  insulates the electro-magnetic conversion element  2  and also enhances the close contact property (i.e, adhesion) between the first DLC film  26  and base material  11 . The Si film  27  enhances the close contact property between the first DLC film  26  and the second DLC film  28 . The first DLC film  26  protects the air bearing surface  3   a  and electro-magnetic conversion element  2 . The second DLC film  28  is processed and becomes the adsorption preventing pad  5 . These films can be formed by film forming techniques such as the sputtering method, CVD method and evaporation or the like. 
     In FIG.  6 ( b ), a first film resist  29  is stacked on the second DLC film  28  using a laminator. 
     In FIG.  6 ( c ), the first resist  29  is covered with a mask pattern for the purpose of exposing and development. As a result, the resist  29  is left only on particular areas  29   a ,  29   b  of the second DLC film  28 . 
     FIG. 7 is a plan view of the disk confronting surface side of the rod type body. FIG.  7 ( a ) shows the rod type body in the condition illustrated in FIG.  6 ( c ). The broken lines in FIG.  6  and FIG. 7 are the cutting lines for dividing the rod type body  12  into individual head sliders. 
     In FIG.  7 ( a ), the hatched area is the area where the first film resist  29  is placed. In the other area, the second DLC film  28  is exposed. As illustrated in FIG.  7 ( a ), the first film resist  29  is classified into the film resist  29   a  having the stripe pattern and the film resist  29   b  having a semi-circular pattern. The former regulates the shape of the air bearing surface  3   a , while the latter the shape of buffer pad  4 . In FIG.  7 ( a ) and FIG.  7 ( b ), the resist  29   b  rides over the cutting line but it is also possible to perform the patterning to remove the resist  29  on the cutting line, as in FIG.  7 ( c ). Thereby, the layer on the cutting line is removed by subsequent ion milling and cutting which may be done easily in the unit of head slider. 
     In FIG.  6 ( d ), ion milling is performed on the rod type body  12 . With the ion milling, the rod type body  12  allows the area not covered with the first resist  29  to be removed up to the upper layer of the basic material  11 . As a result of ion milling, a recess  41  is formed on the rod type body  12  to identify a couple of rails, and a groove  51  is formed to divide the pad and slider rail. 
     In FIG.  6 ( e ), the resist  29  can be removed. 
     In FIG.  6 ( f ), the second film resist  30  is stacked on the second DLC film  28  and the second resist  30  is left only on the surface where the adsorption preventing pad  5  is to be formed, through masking, exposing and development. 
     FIG.  7 ( b ) is a plan view of the disk confronting surface side of the rod type body  12  placed in the condition of FIG.  6 ( f ). 
     In FIG.  7 ( b ), the hatched area indicates the second resist  30 . The second resist  30  regulates the shape of the surface of the adsorption preventing pad  5  to be formed on the air bearing surface  3   a.    
     In FIG.  6 ( g ), the rod type body  12  illustrated in FIG.  6 ( f ) is etched by oxygen plasma. As a result, the second DLC film  28  is selectively etched, leaving the area covered with the second resist  30 . The DLC film  28  which is left becomes the adsorption preventing pad  5 . The etching rate for the Si film  27  by such oxygen plasma is extremely small or zero and the Si film  27  functions as the etching stopper. Therefore, it is not required to control the etching time as precisely as in ion milling, and fluctuation in the amount of etching among a plurality of rod type bodies can be controlled. 
     In FIG.  6 ( h ), the second film resist  30  is removed and the exposed Si film  27  is removed by CF 4  plasma etching. In the CF 4  plasma etching, since the remaining DLC film is not removed, the etching depth of the Si film  27  can be controlled easily. In the figure, the area indicated by the reference numeral  26   a  on the first DLC film  26  becomes the rail  3  and the area indicated by  26   b  becomes the buffer pad  4 . 
     The rod type body  12  shaped to the predetermined shape is removed from the holder  14 . The rod type body  12  is subjected to the polishing process by a polishing apparatus for the purpose of chamfering the DLC film  26   b.    
     FIG. 8 is an external appearance of the polishing apparatus. 
     As illustrated in FIG. 8, the polishing apparatus includes a surface plate  61  and a weight  62 . The polishing surface  65  of the surface plate  61  has a certain curvature and rotates around the rotating shaft. The weight  62  holds the rod type body  12  at the surface opposed to the polishing surface  65  and presses this rod type body  12  to the surface of the surface plate  61  and also rotates by itself on the polishing surface  65 . 
     FIG. 9 is a cross-sectional view of the surface plate  61  along the line passing the center of the surface plate  61 . 
     The polishing surface  65  of the surface plate  61  may be a conic surface as illustrated in FIG.  9 ( a ) or the curving surface as illustrated in FIG.  9 ( b ). Moreover, in regard to the polishing surface  65 , the radius of curvature may be different in the inner circumference and outer circumference as illustrated in FIG.  9 ( c ) and FIG.  9 ( d ). In general, it is easier to form the conic surface rather than to form the curving surface and the surface plate having the shape of polishing surface as illustrated in FIG.  9 ( a ) and FIG.  9 ( c ). 
     FIG. 10 shows the polishing process for the rod type body  12 . 
     As illustrated in FIG.  10 ( a ), an elastic material sheet (rubber plate  63 ) is adhered to the surface of the weight  62  opposing the polishing surface  65 . On the rubber plate  63 , a rod type body  12  is adhered. The rod type body  12  is arranged in its longitudinal direction along the circumference direction of the weight  62 . 
     The rod type body  12  attached to the weight  62  is pushed to the polishing surface  65  of the surface plate  61  as illustrated in FIG.  10 ( b ). The surface plate  61  and weight  62  rotate around the rotating shaft to polish the rod type body  12 . Since the rod type body  12  is rotated on the polishing surface  65  having a curvature, this curvature is transferred to the surface to be polished (surface opposing to the disk) of the rod type body. As a result, the edge of DLC film  26   b  formed on the basic material  11  of the rod type body  12  is removed to form a curving surface. 
     Although the adsorption preventing pad  5  is formed on the head slider illustrated in FIG. 4, this pad is not always required in the present invention. The adsorption pad of the head slider  1  illustrated in FIG. 4 can be omitted by omitting the formation of the Si film  27  and DLC film  28  in the process illustrated in FIG.  6 ( a ) and then selectively etching the first DLC film  26  with ion milling or oxygen plasma using the resist pattern illustrated in FIG.  7 ( a ). 
     FIG. 11 shows the head slider of the second embodiment of the present invention. 
     The head slider illustrated in FIG. 4 allows the buffer pad  4  to be formed on the corner of the basic material  11  but the buffer pad  4  is formed at the position isolated from the corner in the head slider of the second embodiment. The height of the buffer pad is preferably equal to that of the rail. 
     The manufacturing process of the head slider of the second embodiment is almost identical to that of the first embodiment. The difference is that the first film resist  29  is formed in the pattern illustrated in FIG.  7 ( c ) in the process (patterning of the first film resist  29 ) illustrated in FIG.  6 ( c ). Moreover, even in the head slider in the second embodiment, the adsorption preventing pad  5  can be omitted by omitting the Si film  27  and second DLC film  28  in the process illustrated in FIG.  6 ( a ). 
     The buffer pad  4  of the head slider in the second embodiment illustrated in FIG. 11 is formed as a column but it may be an elliptical pillar or a square pillar. Particularly, since the column and elliptical pillar have the curved edge and therefore it assures a certain shock resistance even when the chamfering is not carried out. 
     In the head slider in the first and second embodiments, the height of the slider rail  3  is equal to the height of the buffer pad  4  but the height of the buffer pad  4  may be lower than the slider rail  3 . The manufacturing method of the head slider having the structure explained above will be explained using FIG.  12 . The process up to fixing the rod type body  12  cut out from the wafer to the holder  14  and the polishing process for the rod type body are common to the embodiments explained previously. 
     In FIG.  12 ( a ), the SiC film  25  in the thickness of 5 nm, first DLC film  26  in the thickness of 30 nm, SiC film  27  in the thickness of 3 nm, second DLC film  28  in the thickness of 30 nm, second SiC film  29  in the thickness of 3 nm and third DLC film  30  in the thickness of 30 nm are sequentially laminated on the basic material  11  of the rod type body  12 . 
     In FIG.  12 ( b ), a film resist  31  is formed on the third DLC film  30  and the film resist  31  is processed to the predetermined pattern through the masking, exposing and developing processes. 
     In FIG.  12 ( c ), the rod type body  12  is etched by the ion milling up to the depth of the upper layer part of the basic material  11 . 
     In FIG.  12 ( d ), the film resist  31  is removed and the film resist  32  is formed at the surface of rod type body  12 . Moreover, the resist  32  is left only at the area in which the rail is to be formed through the masking, exposing and developing processes. 
     In FIG.  12 ( e ), the third DLC film  30  on the area where the buffer pad is to be formed is removed by the oxygen plasma etching. 
     In FIG.  12 ( f ), the second Si film  29  exposed at the surface is removed by the CF 4  etching process. 
     In FIG.  12 ( g ), the resist  32  is removed and the film resist  33  is formed at the surface of rod type body  12 . Moreover, the film  33  is left only at the surface where the adsorption preventing pad is to be formed through the masking, exposing and developing processes. 
     In FIG.  12 ( h ), the exposed DLC film  28  and DLC film  30  are removed by oxygen plasma etching. 
     In FIG.  12 ( i ), the resist  33  is removed and moreover exposed Si films  27  and  29  are removed by CF 4  etching. 
     In the head slider of the embodiments explained above, the rail  3  and buffer pad  4  are formed of the same material but these may also be formed of different materials. 
     The process for manufacturing heads including the rail  2  and buffer pad  4  formed of different materials will be explained. 
     In FIG.  13 ( a ), a pad layer  35  which becomes a material of buffer pad  4  is formed to the rod type body  12  on which the rail  3  and adsorption preventing pad  28  are already formed. As the material of pad  4 , C, Si, SiC and SiO 2  may be listed and any suitable method is selected as the film forming method from the sputtering method, CVD method and evaporation method. For the process up to formation of the rail and adsorption preventing pad, various methods used can be utilized. 
     In FIG.  13 ( b ), a resist  36  is formed on the pad layer  35 . 
     In FIG.  13 ( c ), the resist  36  is patterned and it is left only at the surface where the buffer pad is to be formed through the exposing and developing process. 
     In FIG.  13 ( d ), the pad layer  35  not covered with the resist  36  is removed by ion milling or plasma etching. Particularly, when the pad layer  35  is formed of material such as Si and SiC, it is preferable to use CF 4  plasma etching from the point of view of easiness in management of the etching depth. 
     In FIG.  13 ( e ), the resist  36  is removed. Moreover, the exposed Si film  27  is removed by CF 4  etching. When CF 4  plasma etching is used in the step illustrated in FIG.  13 ( d ), it is also effective for removal of the Si film  27  and therefore such etching is not required here. Or, the Si film  27  may be removed before formation of the buffer pad. 
     As explained above, the head slider of the present invention is characterized in that the pad is formed at the side edge of the surface opposing the disk. When the disk apparatus loading the head slider of the present invention receives a shock, the disk is in contact with the pad and contact between the disk and a sharp angle of the head slider may be avoided. Namely, wear of the disk and head slider can be alleviated through loading of the head slider of the present invention. As a result, shock resistance of the disk apparatus can be improved and high reliability can also be assured. 
     While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.