Abstract:
An apparatus and method for lapping and fabricating a read/write head is described. The lapping method includes performing a first lapping process on a structure having the read/write head fabricated therein. The first lapping process is for reducing a first resistive region. The first resistive region is located proximal to a surface of the structure. The first lapping process is for achieving a first lapping benchmark. The lapping method further includes performing a second lapping process on a second resistive region. The second lapping process laps at a rate lesser than the first lapping process. The second lapping process is for achieving a second lapping benchmark. The second resistive region is interposed between the first resistive region and the read/write head. The second resistive region has a different resistive value than the second resistive region.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to magnetic head fabrication. More particularly, the present invention provides a read/write head having a distributed shunt structure for reduced electrostatic discharge and lapping induced.  
       BACKGROUND OF THE INVENTION  
       [0002]     Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.  
         [0003]     The basic hard disk drive model was established approximately 40 years ago and resembles a phonograph. That is, the hard drive model includes a plurality of storage disks or hard disks vertically aligned about a central core that spin at a standard rotational speed. A plurality of magnetic read/write transducer heads, for example, one head per surface of a disk, is mounted on the actuator arm. The actuator arm is utilized to reach out over the disk to or from a location on the disk where information is stored. The complete assembly, e.g., the arm and head, is known as a head gimbal assembly (HGA)  
         [0004]     In operation, the plurality of hard disks are rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are channels or tracks evenly spaced at known intervals across the disks. When a request for a read of a specific portion or track is received, the hard disk drive aligns a head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk drive aligns a head, via the arm, over the specific track location and the head writes the information to the disk.  
         [0005]     Over the years, refinements of the disk and the head have provided great reductions in the size of the hard disk drive. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are generally much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that). Refinements also include the use of smaller components and laser advances within the head portion. That is, by reducing the read/write tolerances of the head portion, the tracks on the disk can be reduced in size by the same margin. Thus, as modern laser and other micro recognition technology are applied to the head, the track size on the disk can be further compressed.  
         [0006]     A second refinement to the hard disk drive is the increased efficiency and reduced size of the spindle motor spinning the disk. That is, as technology has reduced motor size and power draw for small motors, the mechanical portion of the hard disk drive can be reduced and additional revolutions per minute (RPM) can be achieved. For example, it is not uncommon for a hard disk drive to reach speeds of 15,000 RPM. This second refinement provides weight and size reductions to the hard disk drive and increases the linear density of information per track. Increased rates of revolution also provide a faster read and write rate for the disk and decrease the latency, or time required for a data area to become located beneath a head, thereby providing increased speed for accessing data. The increase in data acquisition speed due to the increased RPM of the disk drive and the more efficient read/write head portion provide modern computers with hard disk speed and storage capabilities that are continually increasing.  
         [0007]     Particularly, with regard to data storage devices, these advances have attributed to increases in storage density. However, the increase in storage density has led to a weaker and/or smaller signal strength emitted by each data bit. This has required the development of read/write heads having increased sensitivity to the intensity of the signals emitted by the data bits. Those skilled in the art utilizing techniques for fabricating read/write heads are constantly searching for alternatives that provide increased sensitivity to the read/write head.  
         [0008]     Specifically, within the read/write head fabrication and assembly process, once the read/write head wafer is fabricated and sliced, creating separate head sliders, there is a lapping process. The lapping process thins and polishes the head slider. This lapping process, in part, determines the flying height of the read/write head over the disk, the sensor dimension, and the sensitivity of the sensor.  
         [0009]     Prior art  FIG. 1  shows a conventional lapping environment  10  depicting a common lapping process  66  to be performed on a customarily fabricated and sliced read/write head wafer  15 . Read/write head slider  15  includes a deposition surface  25  upon which the layers and components of the read/write head slider  15  are deposited. Read/write head  15  also includes a surface  20  upon which the lapping process  66  is performed. Surface  20  is commonly referred to as an air bearing surface and is the surface of the read/write head slider  15  that is most proximal to a data bearing surface of the platter upon which a data bit is stored. Slider  15  also includes a sensor  40  for sensing the charge state of data on a data storage device, e.g., a hard disk drive, and for affecting change in data charge state. Lapping process  66  is performed on surface  20  and sensor  40  as indicated by arrows  67 . It is noted that conventional lapping processes, e.g.,  66 , are performed directly on sensor  40  as sensor  40  has been extended to contact surface  20  during fabrication.  
         [0010]     However, because lapping process  66  is applied to sensor  40 , the abrasive quality of lapping process  66  creates a layer material under stress of process  66  that can induce degradation of the magnetic sensor response. In many instances, this degradation can completely disable sensor  40 , thus requiring new wafer fabrication. Further, lapping process  66  can also induce surface damage to sensor  40 . Lapping induced surface damage is known to cause deadening of sensor  66 , rendering the sensor incapable of detecting a charge state of a data bit. Further, by virtue of sensor  40  exposure, conventional lapping process  66  can contribute to electrostatic discharge (ESD), further reducing sensitivity of sensor  40 .  
         [0011]     Further, because of sensor  40  being comprised of one material, e.g., a single element or a composition of elements, there is no detectable resistance difference within the material comprising sensor  40 . Thus, conventional lapping processes are resigned to utilize time of lap and rate of lap to control the lapping process.  
         [0012]     A common solution to achieve a better lap is to cause a smoother (more precise) lapping process  66  that, while slower than a rough lap, can provide a finer lap. It is known that a smoother lap can consume a non-trivial amount of time to achieve proper lapping. Economically, at some point the result achieved with a smoother lap is overshadowed by the amount of time, e.g., cost, required to achieve the desired result.  
       SUMMARY OF THE INVENTION  
       [0013]     A method for lapping a read/write head is described. The present method includes performing a first lapping process on a structure having the read/write head fabricated therein, The first lapping process is for reducing a first resistive region. The first resistive region is located proximal to a surface of the structure. The first lapping process is for achieving a first lapping benchmark. The present method further includes performing a second lapping process on a second resistive region. The second lapping process laps at a rate lesser than the first lapping process. The second lapping process is for achieving a second lapping benchmark. The second resistive region is interposed between the first resistive region and the read/write head. The second resistive region having a different resistive value than the second resistive region.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention:  
         [0015]      FIG. 1  is a prior art block diagram of a read/write head wafer lapping environment in which a conventional lapping process is performed on a conventionally fabricated read/write head wafer.  
         [0016]      FIG. 2A  is an illustrated top-view schematic of components of a hard disc drive upon which embodiments of the present invention can be practiced, in accordance with an embodiment of the present invention.  
         [0017]      FIG. 2B  is an exploded view block diagram of a read/write head component of  FIG. 2A  upon which embodiments of the present invention can be practiced, in accordance with an embodiment of the present invention.  
         [0018]      FIG. 3A  is a block diagram of a fabricated read/write head slider structure in accordance with an embodiment of the present invention.  
         [0019]      FIG. 3B  is a block diagram of a read/write head slider and a lapping process applicable to the read/write head slider of  FIG. 3A , in accordance with an embodiment of the present invention.  
         [0020]      FIG. 3C  is a sequential block diagram illustrating results of a first lapping process applied to the read/write head slider of  FIG. 3B .  
         [0021]      FIG. 3D  is a sequential block diagram illustrating results of a second lapping process applied to the read/write head slider of  FIG. 3B , in accordance with an embodiment of the present invention.  
         [0022]      FIG. 4  is a graph diagram illustrating parameters of a lapping process applied to a read/write head slider, in accordance with an embodiment of the present invention.  
         [0023]      FIG. 5  is a flowchart of a lapping process applied to a read/write head slider in accordance with an embodiment of the present invention.  
         [0024]      FIG. 6  is a flowchart of a method for read/write head slider fabrication and an associated lapping process in accordance with an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0025]     A read/write head lapping process and fabrication technique is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It is noted that one skilled in the art will comprehend that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the present invention.  
         [0026]     Some portions of the detailed descriptions, which follow, are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations that can be performed in the fabrication of read/write heads. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical entities. Usually, though not necessarily always, these entities take the form of structures, elements, or layers implemented in the fabrication of read/write head assemblies. It is usual, although not always, that the manipulations, alone or in combination with computer implemented instructions, are performed by a machine particular to the structure and to the manipulation being performed.  
         [0027]     It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical entities and are merely convenient labels applied to these entities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “forming” or “indicating” or “detecting” or “ceasing” or “lapping” or “implementing” or “reducing” or the like, refer to the actions and processes of a read/write head lapping and/or fabrication process or similar technique that manipulates and transforms those entities into operable read/write devices or other such data storage enabling devices.  
         [0028]     The present invention is discussed primarily in the context of read/write head assemblies, such as a current perpendicular plane (CPP) read/write head. Alternatively, embodiments of the present invention are well suited to be implemented in the fabrication of other read/write heads, such as anistropic magnetoresistive ((A)MR) heads or a giant magnetoresistive (GMR) heads. However, it is noted the present invention can be used with other types of read/write heads and associated fabrication techniques that have the capability to affect access upon a storage device and from which data can be stored and/or otherwise manipulated  
         [0029]     With reference now to  FIG. 2A , a schematic drawing of one embodiment of an information storage system comprising a magnetic hard disk file or drive  200  for a computer system is shown. Drive  200  has an outer housing or base  210  containing a disk pack having at least one media or magnetic disk  215 . The disk or disks  215  are rotated (see arrows  206 ) by a spindle motor assembly having a central drive hub  217 . An actuator  221  comprises a plurality of parallel actuator arms  225  (one shown) in the form of a comb that is movably or pivotally mounted to base  210  about a pivot assembly  223 . A controller  219  is also mounted to base  210  for selectively moving the comb of arms  225  relative to disk  215 .  
         [0030]     In the embodiment shown, each arm  225  has extending from it at least one cantilevered load beam and suspension  227 . A magnetic read/write transducer or head is mounted on a slider  229  and secured to a flexure that is flexibly mounted to each suspension  227 . The read/write heads magnetically read data from and/or magnetically write data to disk  215 . The level of integration called the head gimbal assembly is head and the slider  229 , which are mounted on suspension  227 . The slider  229  is usually bonded to the end of suspension  227 . The head is typically “pico” size (approximately 1250×1000×300 microns) and formed from ceramic or intermetallic materials. The head also may be of “femto” size (approximately 850×700×230 microns) and is pre-loaded against the surface of disk  215  (in the range two to ten grams) by suspension  227 .  
         [0031]     Suspensions  227  have a spring-like quality, which biases or urges the air-bearing surface of the slider  229  against the disk  215  to cause the slider  229  to fly at a precise distance from the disk. A voice coil  233  free to move within a conventional voice coil motor magnet assembly  234  (top pole not shown) is also mounted to arms  225  opposite the head gimbal assemblies. Movement of the actuator  221  (indicated by arrow  235 ) by controller  219  moves the head gimbal assemblies along radial arcs across tracks on the disk  215  until the heads settle on their respective target tracks. The head gimbal assemblies operate in a conventional manner and always move in unison with one another, unless drive  211  uses multiple independent actuators (not shown) wherein the arms can move independently of one another.  
         [0032]      FIG. 2B  is an exploded view of an actuator arm  225  as shown in  FIG. 2A . Upon actuator arm  225  are shown a slider  229  and a read/write head  260  and a sensor  275 . Slider  229  is the intermediate component of  FIG. 2A  which includes a read/write head  260  upon which a read/write head sensor  275  is disposed, in an embodiment of the present invention. Read/write head  260  magnetically reads data from and/or magnetically writes data to disk  215  (not shown). Sensor  275  is for sensing the charge state of a data bit of disc  215  and for affecting a change in the charge state. Sensor  275  is oriented to be operable proximal to the gap between the bottom surface  290  of read/write head  260  (relative to the data bearing surface of disc  215 ) and the data bearing surface of disc  215 . The surface  290  from which sensing is performed by sensor  275  is referred to the air bearing surface (ABS). Embodiments of the present invention provide a lapping and fabrication process for a read/write head  260  including a sensor  275  that are implementable in a disc drive  200 .  
         [0033]      FIG. 3A  is a front-facing block diagram illustrating a read/write head slider  300 , subsequent to the slicing thereof and prior to receiving thereon a lapping process  366 , in an embodiment of the present invention. Slider  300  is implementable as and functionally analogous to slider  229  of  FIGS. 2A and 2B . It is noted that many prior processes have been performed on slider  300  to reach a lapping ready point including, but not limited to, lithography, deposition (vacuum, plating, or sputtering), sensor deposition, shunt deposition, etching, slicing and dicing. Examples of etching processes can include, but which is not limited to, broad-beam ion etching, reactive ion etching, ion-beam etching, polymer etching, and other similar processes. In an embodiment of the present invention, permaloy is used in the fabrication of sensor  305  as well as shunts  335  and  355 . Alternatively, other functionally analogous materials may be used in fabricating sensor  305  and shunts  335  and  355 . In fact, shunt  335 , shunt  355 , and sensor  305  may each be made of alternative functionally analogous materials.  
         [0034]     It is also noted that subsequent to the lapping process as described herein with reference to  FIGS. 3A, 3B ,  3 C,  4 ,  5 , and  6 , slider  300  is subject to additional processes including, but not limited to, subsequent thin film deposition, photolithography, and dry etching that produces a completed read write head slider.  
         [0035]     With continued reference to  FIG. 3A , in one embodiment, subsequent to fabrication and slicing, slider  300  includes a sensor  305 , shunt  335 , and shunt  355 . In an embodiment, shunt  335  and shunt  355  are a resistive material having a resistive value. In one embodiment, shunt  335  can have a greater resistive value than shunt  355 . In an alternative embodiment, shunt  335  can have a lesser resistive value than shunt  355 . In yet another embodiment, shunts  335  and  355  can have similar resistive values. In one embodiment, shunt  335  can have a resistive value of approximately 50 ohms and shunt  355  can have a resistive value of approximately 2 ohms. In the present embodiment, shunt  335  can have, but is not limited to, dimensions of approximately 0.05 micrometers by 2 micrometers. Further, the surface of shunt  355  most remote from sensor  305  can be at a distance of approximately 700 nanometers, prior to lapping process  366 . In the present embodiment, shunt  335  can have, but is not limited to, dimensions of approximately 0.1 micrometers by 1 micrometer. Further, the surface of shunt  335  most remote from sensor  305  can be at a distance of approximately 160 nanometers. It is noted that shunts having alternative resistive values, sizes, and distances (from sensor  305 ) can be implemented in alternative embodiments of the present invention.  
         [0036]     Slider  300  of  FIG. 3A  also includes separations  315 ,  325 , and  345 . Separation  345  is for providing a definitive demarcation between shunt  355  and shunt  335 . Separation  325  is for providing a definitive demarcation between shunt  335  and the point in wafer  300  where sensor  305  is opened. In an embodiment, sensor  305  may be opened at separation  315 . In one embodiment, separations  325  and  345  can provide a separation of 50 nanometers. In an alternative embodiment, separations  325  and  345  may provide varying distances of separation In one embodiment, separation  315  can be utilized for determining the spacer height and can provide 10 nanometers of separation. In an alternative embodiment, separation  315  can be greater than or less than 10 nanometers.  
         [0037]      FIG. 3A  also depicts a lapping process  366  to be performed on slider  300 . In one embodiment, lapping process  366  commences on surface  320 , an air bearing surface (ABS) of slider  300 . Lapping process  366  is applied in an upward direction (relative to wafer  300  of  FIG. 3A ) as indicated by arrow  367 . Arrow  367  includes a first stage lap end point  370  and a second stage lap end point  380 .  
         [0038]     In one embodiment, lapping process  366  can include a first stage lapping process  369  and a second stage lapping process  379 . First stage end point  370  can cause cessation of first stage lapping process  369  and second stage end point  380  can cause cessation of second stage lapping process  380 . In alternative embodiment, lapping process  366  may have fewer or greater stages.  
         [0039]     In an embodiment, first stage lapping process  369  is a coarser lapping process (less precise) than second stage lapping process  379 . In an alternative embodiment, first stage lapping process  369  and second stage lapping process  379  can have the same lapping rate. In yet another embodiment, first stage lapping process  369  is a finer lapping process (more precise) than second stage lapping process  379 . In one embodiment, first stage lapping process  369  has a lapping rate of 300 nanometers per minute. In one embodiment, second stage lapping process  379  can have lapping rate of 30 nanometers per minute. It is noted that varying lapping rates can be implemented in first stage lapping process  369  and second stage lapping process  379  in another embodiment of the present invention.  
         [0040]     In one embodiment, first stage lapping process  369  commences on surface  320  and reduces slider  300  and shunt  355  to first stage end point  370 . First stage end point  370  can be a stopping point of lapping process  369  predicated on time, lapping rate, or a combination thereof, in an embodiment of the present invention. In one embodiment, first stage end point  370  is when first stage lapping process  369  laps to a resistance target of 15 ohms to shunt  335 . In an alternative embodiment, first stage end point  370  can be when first stage lapping process  369  laps to shunt  335 . Alternatively, first stage end point  370  can be determined by a variety of parameters, depending upon the structure and the desired end result. In the present embodiment, upon reaching first stage end point  370 , first stage lapping process  369  is stopped.  
         [0041]     Continuing, subsequent to stopping first stage lapping process  369  at first stage end point  370 , second stage lapping process  379  commences at first stage end point  370  and continues until reaching second stage end point  380 , in one embodiment of the present invention. Second stage end point  380  can be a stopping point of lapping process  379  predicated on time, lapping rate, or a combination thereof, in an embodiment of the present invention. Second stage end point  380  can also be predicated upon detection of an exponential increase in sensor signal amplitude. This increase is an indication that sensor  305  has been uncovered. In one embodiment, second stage end point  380  is when second stage lapping process  379  laps until sensor  305  is opened (uncovered). In the present embodiment, lapping process  366 , particularly second stage lapping process  379  can cease when the sensor amplitude signal shows an exponential increase. Further, because the distance between the remote surface of the shunts  335  and  355  and sensor  305  is a known quantity, a combination of applied lapping force and lap duration can be utilized to predict the second stage end point  380 , in another embodiment of the present invention. In an alternative embodiment, second stage end point  380  can be when second stage lapping process  379  laps through shunt  335  and reaches separation  315 . Alternatively, second stage end point  380  can be determined by a variety of parameters, depending upon the structure and the desired end result. In the present embodiment, upon reaching second stage end point  380 , second stage lapping process  379  is stopped.  
         [0042]     It is particularly noted that through the utilization of shunts  335  and  355 , the lapping process  366  described herein does not directly contact sensor  305  as in conventional lapping techniques. It is noted that shunts  335  and  355  can provide protection against electrostatic discharge (ESD) during wafer fabrication of the read/write head. It is also noted that embodiments of the present invention further provide for protection against ESD occurring during lapping of read/write head  305  of slider  300 . Further, in tunnel-junction read/write heads, embodiments of the present invention protect against smearing of the sensor which is known to cause widely varying signals and which is common during the early stages of a lapping process  366 . It is additionally noted that embodiments of the present invention further provide for a lapping process  366  which provides increased accuracy in read/write heads having a recessed sensor  305 . This enables embodiments of the present invention to provide a decrease in, if not eliminate, instances of material under stress that can damage sensor  305  as well as all but eliminating electrostatic discharge (ESD).  
         [0043]      FIG. 3B  is an initial sequential illustrated diagram of sensor  305  disposed on a slider  300  for showing lapping process  366 , in an embodiment of the present invention. Lapping process  366 , more particularly, first stage lapping process  369  is to commence. Lapping process  366  is applied to slider  300  at surface  320  and is applied in the direction as indicated by arrows  367 . In the present embodiment, first stage lapping process laps at a rate of 300 nanometers per minute and has ceased upon lapping within 15 ohms of shunt  335 , as indicated by first stage end point  370  as shown in  FIG. 3C .  
         [0044]      FIG. 3C  is a second sequential illustrated diagram of sensor  305  disposed on a slider  300  showing lapping process  366  subsequent to cessation of first stage lapping process  369  upon reaching first stage end point  370 , in an embodiment of the present invention. Lapping process  366 , more particularly, second stage lapping process  369  is to commence. Lapping process  366  is applied to slider  300  at surface  320  and at the remainder of shunt  355  and is applied in the direction as indicated by arrows  367 . In the present embodiment, second stage lapping process laps at a rate of 30 nanometers per minute and has ceased upon opening sensor  305 , as indicated by second stage end point  380  as shown in  FIG. 3D .  
         [0045]      FIG. 3D  is a third sequential illustrated diagram of sensor  305  disposed on a slider  300  showing results of lapping process  366  subsequent to cessation of second stage lapping process  379  upon reaching second stage end point  380 , in an embodiment of the present invention. Lapping process  366 , more particularly, second stage lapping process  369  has lapped slider  300  to the point where an exponential increase in sensor signal amplitude is detected, thus indicating opening of sensor  305 .  
         [0046]      FIG. 4  is a graph  400  depicting simulated resistance values associated with lapping process  366 , including first stage lapping process  369  and second stage lapping process  379 , in an embodiment of the present invention. Lapping process  366  is performed upon a read/write head slider  300 , in an embodiment of the present invention.  
         [0047]     Graph  400  includes a resistance line  401 , representing resistance in ohms, on the left side of graph  400 . On the bottom of graph  400  is a time line  402  representing time in seconds. As lapping process  366  is performed, the lapping is represented in a left to right direction and causes the distance between the lapping process commencing surface, e.g.,  320  and sensor  305  to be reduced. Along the right side of graph  400  is line  305 , representing the surface of sensor  305  that is most proximal to the lapping of lapping process  366 . Further, near the top of the right side of graph  400  are track widths  410 ,  420 ,  430 , and  440 , representing the anticipated resistance for a particular track width. In graph  400 , lines  410 ,  420 ,  430 , and  440  represent track widths of 120 nanometers, 100 nanometers, 80 nanometers, and 60 nanometers, respectively. Also included in graph  400  is first lapping process  369  and second lapping process  379 . Further shown are first stage lap end point  370  and second stage lap end point  380 .  
         [0048]     In accordance with an embodiment of the present invention, lapping process  366  is performed on surface  320  of slider  300  as described herein with reference to  FIGS. 3A-3D ,  5 , and  6 . Accordingly, lapping process  366  begins first lapping process  367  on surface  320  of slider  300  and continues lapping into shunt  355 , in one embodiment of the present invention. As first lapping process  369  proceeds, the lapping resistance (Line  401 ) is shown to geometrically increase. At first stage lap end point  370 , first lapping process  369  is stopped. First stage lap end point  370  is at approximately 15 ohms resistance. In an embodiment, first lapping process  369  laps at a rate of 300 nanometers per minute. Because of the coarse (less precise) lapping of first lapping process  369 , there is significant surface scratching and defamation. Accordingly, by ceasing first lapping process  370  at a resistance of 15 ohms, such that a portion of shunt  355  remains, there is adequate material remaining (e.g., in excess of 200 nanometers before sensor contact) such that a finer (more precise) second lapping process  379  can comprehensively remove any surface deformities and/or abnormalities. It is noted that first stage lap end point  370  can be appropriately adjusted to reflect changes is the lapping rate of first lapping process  369 .  
         [0049]     Still referring to  FIG. 4 , second lapping process  379  commences at first stage lap end point  370 , subsequent to cessation of first lapping process  369 , in an embodiment of the present invention. As shown in  FIG. 3C , a portion of shunt  355  remains and upon which second lapping process  379  commences. In the present embodiment, second lapping process  379  laps at a rate of 30 nanometers per minute, although alternative lapping rates could be implemented. Second lapping process  379  continues until reaching second stage lap end point  380  in accordance with an embodiment of the present invention. Second lapping process  379  laps through shunt  355 , separation  345 , shunt  335 , separation  325  and uncovers sensor  305  when lap enters separation  315 , in an embodiment. In an embodiment of the present invention, second stage lap end point  380  can be determined by detecting an exponential increase is sensor signal amplitude, a result of uncovering sensor  305 . Graph  400  also includes track width lines  410 ,  420 ,  430 , and  440 , It is noted that the lapping resistance during second lapping process  379  remains constant once lapping process  379  enters separation  325 . It is noted that as the track width decreases, lapping resistance increases.  
         [0050]      FIG. 5  is a flowchart  500  of a process for steps performed in accordance with one embodiment of the present invention for lapping of a read/write head slider. Flowchart  500  includes processes of the present invention which, in one embodiment, are carried out by fabrication and processing devices and components under the control of computer readable and computer executable instructions. The computer readable and computer executable instructions enable the fabrication and processing of a read/write head slider, e.g., slider  300 . The computer readable and computer executable instructions may reside in any type of computer readable medium. Although specific steps are disclosed in flowchart  500 , such steps are exemplary. That is, the present invention is well suited to performing various other steps or variations of the steps recited in  FIG. 5 . Within the present embodiment, it should be appreciated that the steps of flowchart  500  may be performed by software, by hardware or by any combination of software and hardware for facilitating a lapping of a fabricated and sliced read/write head slider, in an embodiment of the present invention.  
         [0051]     In step  510  of  FIG. 5 , a first lapping process, e.g.,  369 , of a lapping process  366 , as described herein with reference to  FIG. 3A, 3B ,  4 , and  6 , is performed on a fabricated read/write head slider  300  in an embodiment of the present invention. First lapping process  369  commences on surface  320  and laps into shunt  355  until reaching first stage lap end point  370 .  
         [0052]     In step  520  of flowchart  500  of  FIG. 5 , first lapping process  369  has reached first stage lap end point  370  and has ceased lapping, as described herein with reference to  FIGS. 3A, 3B ,  4 , and  6 . In an embodiment, first lapping process  369  laps at a rate of 300 nanometers per minute. In an embodiment, first stage lap end point  370  is at 15 ohms of lapping resistance within shunt  355 , as shown in  FIG. 4 .  
         [0053]     In step  530  of flowchart  500 , a second lapping process  379  of lapping process  366  is performed on read/write head slider  300  in an embodiment of the present invention. Second lapping process  379  commences at first stage lap end point  370  and begins lapping upon the remainder of shunt  355 , in an embodiment and as described herein with reference to  FIGS. 3A, 3C ,  4  and  6 . In an embodiment, second lapping process  379  laps at a rate of 30 nanometers per minute. Second lapping process  379  continues until reaching second stage lap end point  380 .  
         [0054]     In step  540  of flowchart  500 , as second lapping process  379  continues reducing shunt  355 , separator  345 , shunt  335 , separator  325 , and separator  315 , an exponential increase in sensor signal amplitude is detected, as shown in  FIG. 4 . The detection of the increase in sensor signal amplitude indicates uncovering of sensor  305 , in accordance with an embodiment of the present invention.  
         [0055]     Accordingly, in step  550  of flowchart  500 , second lapping process  379  stops at second stage lap end point  380 , in accordance with an embodiment of the present invention.  
         [0056]      FIG. 6  is a flowchart  600  of a process for steps performed in accordance with one embodiment of the present invention for the fabrication and subsequent lapping of a read/write head slider. Flowchart  600  includes processes of the present invention which, in one embodiment, are carried out by fabrication and processing devices and components under the control of computer readable and computer executable instructions. The computer readable and computer executable instructions enable the fabrication and processing of a read/write head slider, e.g., slider  300 . The computer readable and computer executable instructions may reside in any type of computer readable medium. Although specific steps are disclosed in flowchart  600 , such steps are exemplary. That is, the present invention is well suited to performing various other steps or variations of the steps recited in  FIG. 6 . Within the present embodiment, it should be appreciated that the steps of flowchart  600  may be performed by software, by hardware or by any combination of software and hardware for facilitating the fabrication and lapping of a sliced read/write head slider, in an embodiment of the present invention.  
         [0057]     In step  610  of flowchart  600 , a read/write head slider  300  including a sensor  305 , shunts  335  and  355 , and separators  315 ,  325 , and  335  is fabricated in accordance with an embodiment of the present invention and as described herein with reference to  FIG. 3 . Upon fabrication, read/write head  305  is subject to slicing, the process that separates each read/write head  305  from the wafer and becomes part of slider  300 .  
         [0058]     In step  620  of  FIG. 6 , a first lapping process, e.g.,  369 , of a lapping process  366 , as described herein with reference to  FIGS. 3A, 3B , and  4 , is performed on a read/write head slider  300  in an embodiment of the present invention First lapping process  369  commences on surface  320  and laps into shunt  355  until reaching first stage lap end point  370 .  
         [0059]     In step  630  of flowchart  600  of  FIG. 6 , first lapping process  369  has reached first stage lap end point  370  and has ceased lapping, as described herein with reference to  FIGS. 3A, 3B , and  4 . In an embodiment, first lapping process  369  laps at a rate of 300 nanometers per minute. In an embodiment, first stage lap end point  370  is at 15 ohms of lapping resistance within shunt  355 , as shown in  FIG. 4 .  
         [0060]     In step  640  of flowchart  600 , a second lapping process  379  of lapping process  366  is performed on read/write head slider  300  in an embodiment of the present invention. Second lapping process  379  commences at first stage lap end point  370  and begins lapping upon the remainder of shunt  355 , in an embodiment and as described herein with reference to  FIGS. 3A, 3C , and  4 . In an embodiment, second lapping process  379  laps at a rate of 30 nanometers per minute. Second lapping process  379  continues until reaching second stage lap end point  380 .  
         [0061]     In step  650  of flowchart  600 , as second lapping process  379  continues reducing shunt  355 , separator  345 , shunt  335 , separator  325 , and separator  315 , an exponential increase in sensor signal amplitude is detected, as shown in  FIG. 4 . The detection of the increase in sensor signal amplitude indicates uncovering of sensor  305 , in accordance with an embodiment of the present invention.  
         [0062]     Accordingly, in step  660  of flowchart  600 , second lapping process  379  stops at second stage lap end point  380 , as described herein with reference to  FIGS. 3A, 3C ,  3 D,  4 , and  5 , in accordance with an embodiment of the present invention.  
         [0063]     Advantageously, embodiments of the present invention provide a method for fabrication of a read/write head sensor that provides protection against lapping induced sensor damage as well as reducing instances of handling induced ESD. Further, embodiments of the present invention provide a finer (more precise) method of lapping, thus providing an increase in sensor sensitivity.  
         [0064]     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.