Patent Abstract:
A hard disk drive head operates in close proximity and dynamic contact with a rapidly spinning rigid disk surface, the head including a transducer with a magnetically permeable path between a poletip disposed adjacent to the disk surface and a magnetoresistive (MR) sensor situated outside the range of thermal noise generated by the surface contact. The magnetically permeable path is the same as that used to write data to the disk, eliminating errors that occur in conventional transducers having MR sensors at a separate location from the writing poletips. Moreover, the magnetically permeable path is preferably formed in a low profile, highly efficient “planar” loop that allows for manufacturing tolerances in throat height and wear of the terminal poletips from disk contact without poletip saturation or poletip smearing. The MR layer is formed in one of the first manufacturing steps atop the substrate, so that the MR layer has a relatively uniform planar template that is free from contaminants. A preferred embodiment has a laminated yoke for improved high frequency efficiency, with the MR element situated between the yoke lamina for improved sensitivity.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 08/673,281 entitled VIRTUAL CONTACT HARD DISK DRIVE WITH PLANAR TRANSDUCER, filed Jun. 28, 1996, now abandoned, and is also a continuation-in-part of U.S. patent application Ser. No. 08/577,493, still pending, entitled HARD DISK DRIVE HAVING RING HEAD SLIDING ON PERPENDICULAR MEDIA, filed Dec. 22, 1995. Both of these documents are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present invention relates to information storage systems and in particular to electromagnetic transducers for hard disk drives. 
     BACKGROUND OF THE INVENTION 
     Traditional electromagnetic transducers employ a magnetically permeable core coupled with a conductive coil in order to write and read data in an associated magnetic recording surface. In a hard disk drive, such transducers are usually spaced from the rapidly spinning rigid disk by a thin layer of air that moves with the disk surface, often termed an air bearing. This spacing is believed to be important in avoiding damage between the rapidly spinning disk and the transducer, which is appended to a substrate designed to “fly” slightly above the disk surface, buoyed by the moving air layer. This spacing or fly height, however, limits the density with which data can be stored and lowers the resolution and amplitude with which data can be retrieved. In recent years, durable sliding contact operation has been achieved which removes the air layer spacing and thereby enhances resolution, as disclosed in commonly assigned U.S. Pat. No. 5,041,932 to Hamilton. 
     Writing is typically performed by applying a current to the coil so that a magnetic field is induced in the adjacent magnetically permeable core, with the core transmitting a magnetic signal across any spacing and protective coating of the disk to magnetize a tiny pattern, or bit, of the media layer within the disk. Reading of information in the disk is performed by sensing the change in magnetic field of the core as the transducer passes over the bits in the disk, the changing magnetic field inducing a voltage or current in the inductively coupled coil. Alternatively, reading of the information may be accomplished by the employment of a magnetoresistive (MR) sensor, which has a resistance that varies as a function of the magnetic field adjacent to the sensor. In order to increase the amplitude and resolution in reading the bits, the MR sensor is typically positioned on the slider as close to the disk as possible. 
     Such a conventional MR sensor is formed of a very thin film with an edge facing and designed to be aligned with the recorded bits, and is subject to deleterious influences other than the magnetic field of the nearby bits. During manufacture, for instance, minor imperfections in material purity or thickness of the film can result in intolerable variations in magnetoresistance. Similarly, as little as ten millionths of an inch of wear of the sensor due to occasional contact with the disk is enough to cause most currently available, high-density MR hard disk drives to fail. Moreover, fluctuations in the temperature of the sensor can cause changes in resistance that may be confused with magnetic signals. In particular, even occasional contact between the transducer and the disk is known to result in such thermal fluctuations. Differing approaches have been used to avoid such thermal asperities. In U.S. Pat. No. 5,255,141, Valstyn et al. remove an MR or Hall effect sensor from the disk-facing surface of a flying head by utilizing a shunt that is switched to allow sufficient signals for both writing and reading. On the other hand, U.S. Pat. No. 5,455,730 to Dovek et al. employs a thick lubricant and a step to maintain separation between an MR sensor and the disk, and uses electronic manipulation to filter out magnetic signals from thermal noise. 
     An object of the present invention was to provide extremely high signal resolution in a hard disk drive system by designing a transducer to combine dynamic contact operation and MR sensing while keeping the wear and thermal noise from such contact from destroying the transducer or overwhelming the signal resolution. 
     SUMMARY OF THE INVENTION 
     The above object has been achieved in a hard disk drive system having a head in close proximity and therefore frequently if not continuously contacting the rapidly spinning rigid disk surface, the head employing a transducer with a magnetically permeable path between a poletip adjacent the disk surface and an MR sensor situated outside the range of thermal noise generated by the surface contact. The magnetically permeable path is the same as that used to write data to the disk, eliminating errors that occur in prior art transducers having MR sensors at a separate location from the writing poletips. Moreover, the magnetically permeable path is preferably formed in a low profile, highly efficient “planar” loop that allows for manufacturing tolerances in throat height and wear of the terminal poletips from disk contact without poletip saturation or poletip smearing. Due to the high density and signal resolution afforded by such contact, sufficient signal is available for both writing and reading without the need for a shunt circuit. 
     In an ultralight, sliding contact embodiment, the transducer is formed primarily from a composite of thin-film layers with any bulk substrate removed. This transducer is designed to avoid flying and has such a low mass as to be insensitive to wear and shock. At least one disk-facing projection removes the vast majority of the transducer from the air that accompanies the spinning disk, reducing the lift felt by the transducer and allowing the projection to slide on the disk. In a somewhat larger partial or virtual contact embodiment, a substrate die remains attached to the thin-film layers on the side of the slider furthest from the disk, while the disk-facing layers are fashioned for an aerodynamic interaction with the moving air layer that causes the front of the slider to slightly raise while the rearward read/write poletips operate in virtual contact with the disk. 
     In either embodiment, the delicate MR layer is formed in one of the first manufacturing steps atop the substrate, so that the MR layer has a relatively uniform planar template that is free from contaminants. Forming the MR layer on such a flat, contaminate-free surface can dramatically increase the manufacturing yield. Also common to both the ultralight contact and the virtual contact embodiments is a low inductance, generally planar transducer that affords tolerance in throat height, both during manufacturing and later due to operational wear from contacting the disk. One embodiment of the planar transducer has a laminated yoke for improved high frequency efficiency, and the MR element in this case may be situated between the yoke lamina, which are also formed early in the process. 
     The shape of the MR layer is optimized for maximum efficiency and stability. Additional stability may be provided by exchange, permanent bias, end pinning or any other suitable stabilization device. The preferred means for linearizing the MR output signal, in order to distinguish the orientations of recorded bits, is by flowing the electric current in the MR element in a direction between parallel and perpendicular to the magnetic flux from a signal. This canted current flow may be achieved by defining conductors adjoining the MR element, and a stabilization layer may optionally first be deposited on the MR element. Other linearizing and stabilizing schemes may employ a soft adjacent underlayer (SAL), permanent magnet layer, end pinning or other devices. The poletips are formed last, allowing for careful tailoring and last-minute variations in track width and other specifications. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of a virtual-contact, magnetoresistive-sensing head of the present invention. 
     FIG. 2 is a bottom view of the disk-facing surface of the head of FIG.  1 . 
     FIG. 3 is a cross-sectional view of an ultralight-contact, magnetoresistive-sensing integrated flexure head of the present invention. 
     FIG. 4 is a bottom view of the disk-facing surface of the head of FIG.  3 . 
     FIG. 5 is a cross-sectional view of an ultralight-contact, magnetoresistive-sensing integrated flexure head of the present invention. 
     FIG. 6 is a top view of the integrated head and flexure of FIG.  5 . 
     FIG. 7 is a top view of some initial steps in forming an MR sensor in a laminated yoke. 
     FIG. 8 is a cross-sectional view of the steps of FIG.  7 . 
     FIG. 9 is a top view of steps subsequent to those shown in FIG. 7 in forming an MR sensor in a laminated yoke. 
     FIG. 10 is a cross-sectional view of the steps of FIG.  9 . 
     FIG. 11 is a cross-sectional view of steps of forming a coil and gently curving laminated yoke coupled to the yoke of FIG.  9 . 
     FIG. 12 is a cross-sectional view of the formation of a pedestal for the gently curving yoke of FIG.  11 . 
     FIG. 13 is a cross-sectional view of the formation of poletip and gap layers adjoining the yoke of FIG.  11 . 
     FIG. 14 is a cross-sectional view of the etching of the poletip layers of FIG.  13 . 
     FIG. 15 is a top view of the etching of the poletip layers of FIG.  13 . 
     FIG. 16 is a cross-sectional view of the creation of a durable pad encasing the poletips of FIG.  14 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a cross-section of a virtual contact head or slider  30  in operation reading or writing data on an adjacent rigid disk  32 , while FIG. 2 shows a view of that head as seen from the disk. The arrows  1 — 1  in FIG. 2 indicate the cross sectional view of FIG.  1 . The slider  30  has a transducer  33  with a magnetically permeable loop or core  35  which is used for both inductive writing and magnetoresistive (MR) reading of bits of data on a media layer  36  of the disk  32 . An MR stripe  38  forms a small part of the loop  35  through which magnetic flux passes during both writing and reading. A projection  40  from a disk-facing surface  42  of the slider has a pair of poletips  44  which are exposed to a recording surface  48  of the disk  32 . The projection  40 , aside from the poletips  44 , is composed essentially of diamond-like-carbon (DLC), which has a favorable tribological relationship with a carbon based layer  50  that overcoats the media layer  36  of the disk  32 . The disk  32  spins relative to the head  30  in a direction shown by arrow  52  at a typical operational speed of several thousand RPM, generally between 2,000 and 10,000 RPM. 
     As will be described in more detail below, the head is constructed in a series of layers which will be mostly parallel to the disk surface  48  during operation, including in this embodiment a substrate  53  upon which the remainder of the layers are formed. The magnetically permeable core  35  is formed of several ribbon-like layers, which in this cross-sectional view are shaped similar to the body of a coat hanger, with the MR stripe  38  disposed near a center of the base and opposed to the poletips  44 . A layer of coils  54  winds around the core  38  in a connected pair of spirals that induce a magnetic flux around the core during writing of signals, the coils provided with voltage through conductors that run along or through the substrate  53  at locations not shown in this cross-section. The flux travels across a gap between the poletips  44  and into the media  36  to magnetize bits of the media. During reading, the magnetic fields from the bits of media  36  cause a magnetic flux to flow around the core  35  including the MR stripe  38 , which is connected by conductive leads to a circuit that senses a change in resistance of the stripe caused by the magnetic field in the core. 
     The disk-facing surface  42  has an air bearing projection  58  near the leading edge  60  that maintains that edge at a higher elevation from the disk  32  than the trailing edge  62 . In front of the air bearing surface  58  is a shallow ramp or step  63  that provides an upward tilt to the slider during start up. Behind the U-shaped projection  58  is a recessed, negative pressure area  64  that adjoins the trailing, magnetically active projection  40 . A balance between the downward forces provided by the negative pressure area  64  and the head suspension, and the upward forces provided by disk surface contact and the aerodynamic lift of the small projection  40 , keep that projection and its exposed poletips  44  in virtual contact with the disk surface, allowing durable, high density data storage and retrieval. The proximity of the poletips to the magnetized bits of the disk allows sufficient signal to propagate around the core for sensing by the MR circuit, and the insulation of the MR stripe from thermal asperities generated by dynamic contact between the projection  40  and the disk  32  keeps noise generated by heat at a minimum. 
     An ultralight head  68  is seen in FIG.  3  and FIG. 4 to also have a body with a projection  70  for operational contact with a rigid disk surface, a magnetically permeable core  72  terminating in a pair of poletips  75  exposed at a tip of the projection and an MR sensor  77  coupled to the core opposite to the poletips. The arrows  3 — 3  in FIG. 4 indicate the cross sectional view of FIG.  3 . Like the virtual contact head outlined above, the ultralight body is built in a series of thin-film layers atop a wafer substrate, the layers designed to be mostly parallel to a magnetic recording surface of a disk. Unlike the virtual contact head, however, the ultralight head is completely removed from the substrate to leave a body formed entirely of thin films. The ultralight head is also designed to have three projections or legs  70 ,  80  and  82  to stabilize contact with the disk during information storage or retrieval, and to avoid aerodynamic lift of even the leading edge of the chip. 
     A magnetically permeable core  72  shown in FIG. 3 has a similar shallow ribbon shape that loops around a coil layer  78  as the gently curved core  35  depicted in FIG. 1, but the core  72  shown in the ultralight head is laminated for improved high frequency performance. That is, a pair of approximately micron thick magnetically permeable layers  84  and  86  are separated by a thin nonmagnetic layer  88  along a generally flat first yoke, and a similar pair of magnetically permeable ribbons  92  and  94  are separated by a thin a magnetic layer  96  along a gently curving second yoke  98 . The MR sensor  77  is a stripe that is parallel with layers  84  and  86  and disposed within a magnetic layer  88 . The MR stripe  77  has a thickness of a few hundred angstroms and may be biased by a canted current conductor formation, a soft adjacent layer, a permanent magnet layer or exchange coupled layer, and is located between closely adjacent layers of the laminated core for improved efficiency. As with the previous embodiment, the efficiency of the planar transducer combined with contact or virtual contact between the magnetic core and the disk allows MR sensing without the use of a shunt. Since reading is performed with the MR sensor  77 , only a single coil layer is used for writing, which mitigates thermal noise from the coil. The thermally conductive second yoke  98  diverts heat away from the MR sensor  77 , while the various alumina layers disposed between the poletips  75  and the sensor  77  shield the sensor from thermal asperities from the head-disk interface. 
     FIG.  5  and FIG. 6 show an ultralight contact, integrated head and flexure beam  100  with a transducer  102  having an MR sensor  105  coupled to a magnetically permeable core  110  at a position opposed to that of a pair of poletips  112 , the poletips being exposed at the end of a disk-facing projection  115 . The arrows  5 — 5  in FIG. 6 indicate the cross sectional view of FIG.  5 . The integrated head and flexure beam  100  is formed, like the ultralight head, on a substrate along with thousands of like beams, from which it is thereafter removed. A split coil layer  117  winds symmetrically around and through the core  110 , with a pair of interconnects  119  providing leads to inner rings of the spiral coil  117 , the interconnects providing a conductive link to a pair of write conductors  122  and  123  that extend along a side of the flexure beam  100 . The MR sensor  105  is similarly connected to a pair of read conductors  124  and  125  that extend along an opposite side of the beam  100 . The beam  100  has a tapered shape and is divided into a pair of hinge strips  127  and  130  which are connected by braces  133 ,  135  and  137 . A mounting end  139  of the beam  100  has a void  140  which allows swage attachment to a baseplate without damage to the beam. Near the mounting end  139  conductors  122 ,  123 ,  124  and  125  are exposed at pads  142 ,  143 ,  144  and  145 , respectively, for connection with drive system electronics. Substantially continuous contact of the head  100  with the disk as provided by this embodiment may help to mitigate thermal fluctuations caused by occasional contact. 
     A preferred construction of the laminated yoke MR sensor  77  utilizing canted current biasing is shown in FIGS. 7-10, which depict early steps in the process of forming the transducer. The arrows  7 — 7  in FIG. 8 indicate the cross sectional view of FIG. 7, while in FIG. 9 the arrows  10 — 10  indicate the cross sectional view of FIG.  10 . Similarly, the arrows  8 — 8  in FIG. 7 indicate the cross sectional view of FIG. 8, while in FIG. 10 the arrows  9 — 9  indicate the cross sectional view of FIG.  9 . The MR sensor  77  and magnetic layers  84  and  86  are formed of “permalloy” (approximately Ni 0.8 Fe 0.2 ) layers which, although separated by the insulative layer  88  and gaps in the magnetic layers, are magnetically coupled to form the first yoke  90 . Magnetically permeable yoke layer  84  is formed first, atop either an insulative layer  150  such as polished alumina or silicon nitride or, for the situation in which the wafer die will remain as part of the finished slider, optionally formed directly upon a wafer substrate  152  made of an insulative material such as alumina, silicon nitride or nonconductive silicon carbide. For ultralight embodiments such as were shown in FIGS. 3-6, a copper layer is typically formed between the wafer  152  and insulative layer  150  so that the transducers can be released from the wafer after they are built. The wafer  152  and/or the insulative layer  150  are traversed with electrical leads, not shown, to allow electrical connection between the transducer and drive electronics. 
     Magnetically permeable layer  84  has been formed by window frame plating to a thickness of several microns, with an a magnetic gap  155  in the layer  84  formed adjacent to sensor  77 . To increase magnetic flux through that sensor, the gap is typically filled with an alumina layer that is polished along with magnetic layer  84  to leave each with a thickness between about 1 μm and 3 μm. The yoke layer  84  has an easy axis of magnetization shown by arrow  153  and can also be seen in FIG. 7 to be tapered adjacent to sensor  77 , also in order to channel flux through the sensor. A thin layer  157  of alumina is then sputtered and polished to a thickness of approximately 250 Å-2000 Å, providing a smooth, contaminate free surface for forming the sensor. Forming the MR stripe  77  begins with sputtering a permalloy film to a thickness of about 200 Å, the film having an easy axis of magnetization generally parallel to that of layer  84  and double headed arrow  153 . The film is then covered with a patterned photoresist and ion beam etched to define a generally rectangular stripe extending about 5 μm longitudinally and about 30 μm laterally, although the exact dimensions of the stripe may vary from these figures substantially, depending upon tradeoffs involved in maximizing efficiency and stability. 
     The IBE that defines the outline of the MR stripe  77  may simply remove a window frame shaped border around the stripe, leaving the remainder of the permalloy film as a seed layer for the magnetic layer  86  and a pair of conductive leads  160  and  162  that will be formed later. Alternatively, as shown, the IBE may remove all of the thin permalloy aside from the rectangular stripe  77 . Next, a conductive pattern is formed which provides the leads  160  and  162  to the MR stripe  77 , the leads having respective slanted edges  165  and  168  which are parallel with each other and with edges of a parallelogram shaped conductive bar  170  formed therebetween. A bias layer formed of a permanent magnet or an antiferromagnetic material such as FeMn optionally underlies the conductive pattern adjoining the MR stripe  77 , in order to pin the magnetization of that stripe in the direction of arrow  172 . The leads  160  and  162  and conductive bar  170  are so much more electrically conductive than the MR stripe  77  that an electrical current between leads  160  and  162  in sections  177  of the MR stripe not adjoining leads  160  and  162  or bar  170  flows along the shortest path between the slanted edges  165  and  168  and bars as shown by arrows  180 , essentially perpendicular to those edges and the parallel sides of the intervening bar  170  and at a slant to the easy axis direction  172 . 
     An amagnetic, insulative and preferably alumina layer  182  is sputtered to a thickness of approximately 100 Å-1000 Å on top of the MR stripe  77 , conductive leads  160  and  162 , conductive bar  170  and alumina layer  157 , so that adjoining alumina layers  157  and  182  together form the thin a magnetic layer  88  that separates magnetic layers  84  and  86  for improved high frequency performance. Magnetic layer  86  is then formed atop alumina layer  182  by sputtering a NiFe seed layer and window frame plating to leave a magnetically permeable layer  86  adjacent to and shaped like layer  84 , which together with stripe  77  forms the first yoke  90 . Layer  86 , like layer  84 , tapers toward a gap adjacent to MR stripe  77 , so that magnetic flux from the layers  84  and  86  is encouraged to pass through MR stripe  77 . Another alumina layer  185  is then deposited atop the wafer, filling the gap in layer  86 , after which the wafer is polished flat to the point at which layer  86  has generally the same thickness as layer  84 . 
     The magnetoresistance of the MR stripe  77  varies depending upon an angle θ between the magnetic field and the electric current in the stripe such that the resistance is generally proportional to cos 2 θ. The direction of electric current in stripe  77  is held constant as shown by arrow  190 , which is parallel to current arrows  180 , while the direction of magnetization can change depending upon the flux in the yoke  90 . In the absence of a magnetic field from the yoke layers  84  and  86 , the angle θ between the easy axis  172 , along which the magnetization of the stripe  77  is directed, and the direction of electric current in magnetoresistive sections  177  as shown by arrow  190 , is between 0° and 90° and preferably near 45°. Upon receiving a magnetic signal from a disk by a pair of poletips coupled to the yoke layers  84  and  86 , so that a magnetic flux in those sections is directed as shown by arrows  192 , the magnetic moment of the stripe  77  is rotated in a direction more parallel with current arrows  180  so that the magnetoresistance in sections  177  approaches zero. On the other hand, when a magnetic pattern on the disk creates a magnetic flux in the yoke layers  84  and  86  in a direction of arrow  194 , the magnetic moment within MR stripe  77  is rotated to become more nearly perpendicular to current direction  180  within resistive sections  177 , so that magnetoresistance in those sections  177  rises. This differential resistance based upon the direction of magnetic flux in yoke layers  84  and  86  creates a voltage difference which is used to read the information from the disk. Alternatively, the MR sensor could be formed with a soft adjacent layer (SAL) or other known bias schemes, or could instead be a spin-valve, giant magnetoresistive (GMR) or multilayered, colossal magnetoresistive sensor using techniques known to those skilled in the art. 
     As is apparent in the broader view of FIG. 11, during the previously described formation of first yoke  90  and sensor  77  a pair of conductive leads  195  and  197  have been concomitantly formed in segments to provide electrical current through a soon to be described transducer coil used for writing. A silicon carbide etch stop layer  196  is sputtered to a thickness of a few thousand angstroms atop yoke layer  86 , alumina layer  185  and lead  195 , after which lead  195  is exposed by IBE. An extension of lead  195  is then plated through a hole in a photoresist exposing that lead, after which the resist is removed and another alumina layer  200  is sputtered and lapped flat to a thickness of a few microns on top of etch stop  196 . A NiFeMo or Ti/Cu seed layer is then sputtered, then covered with another photoresist layer which is patterned with a pair of oppositely circling spirals that are connected at a crossover winding adjacent to sensor  77 , and then electroplated with copper to form a coil layer  202 , which is connected with the lead  195 . The patterned spiral resist is then removed as is the seed layer between coils, to leave the coil layer  202  which spirals outwardly from leads  195  and  197  to meet at crossover winding  205 . A layer  207  of alumina is deposited on and about the coil  202 , then lapped flat to leave a few microns atop the coil. An etch-stop layer  210  of SiC is then deposited to cover alumina layer  207 , masked and patterned by IBE to remain atop the coil spirals  202 , for protection during isotropic etching of a later formed alumina layer  218 , the etching creating a sloping pedestal  220 . 
     FIG. 12 details the pedestal creation, in which alumina layer  218  is formed on top of etch-stop  210 , the alumina layer polished and covered with a MoNiFe cap  222  adjacent to crossover winding  205 , so that isotropic chemical etching of that alumina layer  218  forms the pedestal  220  with sloping sides, after which the cap and the etch-stop  210  not covered by pedestal  220  are removed. Apertures in a photoresist are then formed over the ends of yoke  90 , allowing another isotropic etch to produce the sloping sides  212  and  213  adjacent to the ends of yoke  90  and above etch stop  196 . This etch stop  196  may then be removed from the bottom between the sloping sides by IBE or RIE. A first gently curving yoke layer  225  of NiFe is then formed by window frame plating, the sloping sides  212  and  213  allowing the ends of that layer to adjoin the ends of yoke  90 , while projecting away from sensor  77  atop the pedestal  220 . A thin, a magnetic layer of alumina  230  is then sputtered on the yoke layer  225 , after which a second gently curving yoke layer  233  is window frame plated atop the first  225 , separated by the thin a magnetic layer  230  to form an efficient, gently curving second yoke  215 . Another alumina layer  235  is deposited on second yoke  215  and then lapped along with the portion of yoke  215  projecting above the pedestal  220  until yoke layer  225  is separated into two sections over the pedestal, with a gap between the sections. 
     FIG. 13 shows the formation of a pair of poletips atop the separated second yoke  215 , beginning with the window frame plating of permalloy or other magnetically permeable material to form a first pole layer  237 , preferably of NiFe, leaving an essentially vertical edge  238  disposed over the gap in the yoke  215 . A thin (approximately 2000 Å) layer  240  of high magnetic saturation (high B S ) material such as FeAl(N) is then sputtered over pole layer  237  and edge  238  and then photomasked and trimmed by IBE to avoid connecting the separated sections of yoke layer  215  with a high B S  path, leaving a vertical high B S  section  241 . A thin layer  242  of a magnetic material such as hydrogenated carbon, SiC or Si is then similarly deposited, creating an essentially vertical section  245  formed adjacent to the edge  238 , which will become an a magnetic gap between the poletips. Although the section  245  of a magnetic material that will become the gap is formed on essentially vertical sides of the pole and high B S  layers  238  and  241  that may be at least several microns in height, a uniform thickness of the high B S  section  241  adjoining edge  238  and gap section  245  are formed by sputtering in a vacuum chamber while positioning the platform holding the wafer on which the transducers are being formed such that the sputtered material impinges upon the edge  238  of the pole layer  237  as well as the top of that layer. This uniform formation on a vertical edge can be accomplished by rotating or transporting the wafer across the base of the sputtering chamber, or simply by positioning the wafer at a location at which the sputtering material as an angled approach. The a magnetic layer  242  is then trimmed, leaving gap section  245 . A second high B S  layer  247  is then sputtered over the previously formed layers to form, in part, another essentially vertical high B S  section  250 , the layer  247  then optionally masked and etched by IBE along the mask edge so that the vertical section  250  is connected to the yoke  215 . A second pole layer  255  is formed by window frame plating or sheet plating, after which the wafer is lapped flat, exposing first pole layer  237  and tips of the gap  245  and high B S  sections  250  covering a magnetic layer  150  and alumina layer  144 . The dimensions of the vertical gap  245  that face a disk will set the magnetic resolution during communication between the transducer and conventional longitudinal media, the width of the gap  245  being uniform and typically between about 0.05 μm and 0.4 μm, and preferably about 0.20 μm currently. 
     Referring now to FIG.  14  and FIG. 15, a photoresist mask  260  has been formed in an elongated hexagonal shape desired for a pair of poletips  264  and  266 , however, the mask  260  is larger than the eventual poletip area, to compensate for removal of a portion of the mask during etching. The etching is done by IBE with the ion beam directed at a preselected angle α to the surface of the pole layers  237  and  255 , while the wafer is rotated, in order to form vertical sides of the poletips  264  and  266 . This angled, rotating IBE also forms a tapered skirt  268  of the poletips  264  and  266 , the skirt  268  acting as an aid to the subsequent formation of the DLC that will surround the poletips, since the absence of an acute, shadowed corner mitigates formation of weakened regions in the DLC which tend to crack. The vertical sides of the poletips  264  and  266  allows operational wear of the poletips to occur without changing the magnetic track width of the head. On the other hand, the skirt  268  allows the DLC that wraps around the poletips  264  and  266  to be formed without cracks or gaps which can occur, for example, in depositing DLC by plasma enhanced chemical vapor deposition (PECVD) onto a vertically etched pair of poletips. Although this tapered skirt  268  can be achieved by a variety of techniques, an angled, rotating IBE is preferred that exactingly tailors both the vertical poletips  264  and  266  and tapered skirts  268 . 
     As shown in FIG. 14, the photoresist mask  260  has an etch rate that is similar to that of the NiFe pole layers  237  and  255 , so that when the angle α is approximately 45° the pole layer  255  and the mask  260  are etched a similar amount, as shown by dashed line  270 . Pole layer  237 , however, is partially shielded from the angled IBE by the mask  260 , so that a portion of layer  237  that is adjacent to the mask is not etched, while another portion is etched as shown by dashed line  272 . As the wafer substrate is rotated during etching, layer  255  will have a non-etched portion adjacent to an opposite end of the elongated mask  260 , as will areas adjacent to the sides of the elongated mask. The angle a may be changed to further control the shaping of the poletips  264  and  266 , for example to employ a greater angle such as about 60° toward the end of the IBE. This rotating, angled IBE is continued for an appropriate time to create a pair of poletips  264  and  266  having vertical sides with a tapered skirt  268  and a flat, elongated hexagonal top centered about the gap  245 . 
     The wafer and multiple transducers are then ready for the formation of the disk-facing surface of each transducer, including features such as the trailing pad  40  and air bearing pad  58  of the virtual-contact embodiment, the triad of pads  70 ,  80  and  82  of the ultralight-contact slider, or the unitary projection  115  of the ultralight-contact, integrated flexure head. Since each embodiment has a pad or projection encompassing the poletips, FIG. 16 focuses on the formation of such a magnetically active pad for clarity. An adhesion layer  280  of Si is deposited to a thickness of about 1000 Å atop the poletips  264  and  266  and alumina layer  235 . A layer  282  of DLC is then deposited by PECVD onto the adhesion layer  280 . An approximately 1500 Å thick layer  285  of NiFe is then sputter deposited, which is then patterned by IBE with a lithographically defined photoresist mask  288  to leave, after IBE, a NiFe mask  290  disposed over the DLC covered poletips  264  and  266 . The DLC layer  282  covered with the NiFe masks is then RIE etched along edges  292  with O 2  plasma to leave projections  295  of DLC that encase the poletips, with any other disk-facing projections also being formed at this time. The pads  295  are then lapped to expose the poletips  264  and  266 . The heads are now divided from each other by either dicing of the wafer to yield virtual-contact heads or chemically dissolving the release layer to yield ultralight-contact heads.

Technology Classification (CPC): 6