Patent Publication Number: US-8524095-B2

Title: Process to make PMR writer with leading edge shield (LES) and leading edge taper (LET)

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the present invention generally relate to leading edge shields and magnetic heads for data recording, and more particularly to a method for manufacturing a leading edge shield and a perpendicular magnetic write head having a tapered write pole. 
     2. Description of the Related Art 
     The heart of a computer&#39;s long term memory is an assembly that is referred to as a magnetic disk drive. The magnetic disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension arm adjacent to a surface of the rotating magnetic disk, and an actuator that swings the suspension arm to place the read and write heads over selected circular tracks on the rotating disk. The read and write heads are directly located on a slider that has an air bearing surface (ABS). The suspension arm biases the slider toward the surface of the disk, and when the disk rotates, air adjacent to the disk moves along with the surface of the disk. The slider flies over the surface of the disk on a cushion of this moving air. When the slider rides on the air bearing, the write and read heads are employed for writing magnetic transitions to and reading magnetic transitions from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions. 
     The write head has traditionally included a coil layer embedded in first, second and third insulation layers (insulation stack), the insulation stack being sandwiched between first and second pole piece layers. A gap is formed between the first and second pole piece layers by a gap layer at an air bearing surface (ABS) of the write head and the pole piece layers are connected at a back gap. Current conducted to the coil layer induces a magnetic flux in the pole pieces which causes a magnetic field to fringe out at a write gap at the ABS for the purpose of writing the aforementioned magnetic transitions in tracks on the moving media, such as in circular tracks on the aforementioned rotating disk. 
     In recent read head designs, a GMR or TMR sensor has been employed for sensing magnetic fields from the rotating magnetic disk. The sensor includes a nonmagnetic conductive layer, or barrier layer, sandwiched between first and second ferromagnetic layers, referred to as a pinned layer and a free layer. First and second leads are connected to the sensor for conducting a sense current there-through. The magnetization of the pinned layer is pinned perpendicular to the air bearing surface (ABS) and the magnetic moment of the free layer is located parallel to the ABS, but free to rotate in response to external magnetic fields. 
     In order to meet the ever increasing demand for improved data rate and data capacity, researchers have recently been focusing their efforts on the development of perpendicular recording systems. A traditional longitudinal recording system, such as one that incorporates the write head described above, stores data as magnetic bits oriented longitudinally along a track in the plane of the surface of the magnetic disk. This longitudinal data bit is recorded by a fringing field that forms between the pair of magnetic poles separated by a write gap. 
     A perpendicular recording system, by contrast, records data as magnetizations oriented perpendicular to the plane of the magnetic disk. The magnetic disk has a magnetically soft underlayer covered by a thin magnetically hard top layer. The perpendicular write head has a write pole with a very small cross section and a return pole having a much larger cross section. A strong, highly concentrated magnetic field emits from the write pole in a direction perpendicular to the magnetic disk surface, magnetizing the magnetically hard top layer. The resulting magnetic flux then travels through the soft underlayer, returning to the return pole where it is sufficiently spread out and weak that it will not erase the signal recorded by the write pole when it passes back through the magnetically hard top layer on its way back to the return pole. 
     In a perpendicular magnetic recording system, it is desirable to maximize write field strength and also maximize field gradient. A strong write field ensures that a magnetic bit can be recorded in the magnetically hard top layer of the magnetic medium. A high field gradient allows for fast magnetic switching of the magnetic field from the write pole, thereby increasing the speed with which the magnetic transitions can be recorded. 
     Some of the problems encountered with perpendicular recording are side writing and side erasure to adjacent tracks on the disk. These problems occur from leakage and fringing of the magnetic flux from the magnetic write head. To minimize these effects, one approach is to provide either a trailing or wrap-around shield on the magnetic write head. The wrap-around shield head has the main pole surrounded on three sides by three shields from the air bearing surface view. These shields allow effective magnetic flux to be provided for writing to the disk, while avoiding leakage and fringing that can lead to the above-described problems. Another solution is to use a slanted pole on the trailing side of a writer. However, both solutions exhibit limitations as higher recording area density are sought for current and future products. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention generally relate to leading edge shields and magnetic write heads, and more specifically to fabrication of leading edge shields and tapered structures within the magnetic heads. 
     One embodiment of the invention provides a method for fabricating a magnetic head. The method generally comprises providing a substrate having a first non-magnetic material disposed thereon, a feature definition formed in the first non-magnetic material, and a first magnetic material disposed in the feature definition, wherein the feature definition has a trapezoidal cross-sectional shape and the first magnetic material forms a planar surface in the feature definition, depositing a second magnetic material on the planar surface, forming a patterned resist material on the second magnetic material to expose a portion of the second magnetic material, etching the exposed second magnetic material to form at least one tapered surface of the second magnetic material, removing the patterned resist material, depositing a second non-magnetic material on the second magnetic material having at least one tapered surface, depositing a third non-magnetic material on the second non-magnetic material, and planarizing the second non-magnetic material and the third non-magnetic material to the surface of the second non-magnetic material. 
     Another embodiment of the invention provides a method for fabricating a magnetic head. The method generally comprises forming a magnetic leading edge shield in a substrate surface, the leading edge shield having a planar surface that tapers from the planar surface to an underlying portion of the substrate surface, depositing a magnetic leading edge material on the leading edge shield material, patterning a resist material on the magnetic leading edge material, wherein the patterned resist material exposes a portion of the magnetic leading edge material, etching the exposed portion of the magnetic leading edge material using the patterned resist material as a mask, wherein the etching removes the exposed portion of the magnetic leading edge material to form one or more tapered surfaces, depositing an etch stop layer over the magnetic leading edge material having one or more tapered surfaces, depositing a bulk fill material over the etch stop layer, and planarizing the bulk fill material to the etch stop layer. 
     Another embodiment of the invention provides one embodiment of a magnetic head. The magnetic head generally comprises a non-magnetic, electrically insulating material, a leading edge shield formed on the non-magnetic, electrically insulating material, a leading edge taper formed on the leading edge shield with the leading edge taper tapering away from an air bearing surface (ABS) end of the magnetic head, a write pole formed on the leading edge taper and the leading edge shield and having a tapered region having a tapered trailing edge portion and a non-tapered region, wherein a thickness of the tapered region of the write pole increases in a direction away from an air bearing surface (ABS) end of the magnetic head, a first non-magnetic layer formed on the non-tapered region of the magnetic pole, a non-magnetic bump layer formed on the tapered region, wherein the non-magnetic bump layer is adjacent to a sidewall portion of the first non-magnetic layer, a second non-magnetic layer formed on a portion of the tapered region of the write pole that is not covered by the bump layer, and a trailing edge shield formed on the tapered region, wherein the trailing edge shield is separated from the write pole by at least the second non-magnetic layer and the bump layer. 
     In another embodiment, method of fabricating a leading edge shield is disclosed. The method includes depositing a chemical mechanical polishing stop layer over a substrate, forming a photoresist mask over the chemical mechanical polishing stop layer, and etching at least a portion of the chemical mechanical polishing stop layer and at least a portion of the substrate to form a feature definition. The method also includes removing the photoresist mask to expose the chemical mechanical polishing stop layer, depositing leading edge shield material into the feature definition and over the exposed chemical mechanical polishing stop layer, chemical mechanical polishing the leading edge shield material to expose the chemical mechanical polishing stop layer, and removing the chemical mechanical polishing stop layer. 
     In another embodiment, a method of fabricating a leading edge shield is disclosed. The method includes forming a photoresist mask over a substrate, etching at least a portion of the substrate to form a feature definition, and removing the photoresist mask to expose the substrate. The method also includes depositing a chemical mechanical polishing stop layer over the substrate and in the feature definition, depositing leading edge shield material over the chemical mechanical polishing stop layer, chemical mechanical polishing the leading edge shield material to expose at least a portion of the chemical mechanical polishing stop layer, and removing the exposed portion of the chemical mechanical polishing stop layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
         FIG. 1  is a schematic illustration of a disk drive system in which the invention might be embodied; 
         FIG. 2  is an air bearing surface (ABS) view of a slider, taken from line  2 - 2  of  FIG. 1 , illustrating the location of a magnetic head thereon; 
         FIG. 3  is a cross sectional view of a magnetic write head according to an embodiment of the present invention; 
         FIG. 4A  is a cross sectional view of a pole tip region of a write head according to an alternate embodiment of the invention; 
         FIG. 4B  is an air bearing surface (ABS) view of the write head of  FIG. 4A , as viewed from line B-B of  FIG. 4A ; 
         FIGS. 5A-5G  illustrate an exemplary method for forming a leading edge shield and leading edge taper for a flared write pole according to an embodiment of the invention; 
         FIGS. 6A-6E  illustrate one embodiment of a method for forming a leading edge shield according to an embodiment of the invention; 
         FIGS. 7A-7E  illustrate another embodiment of a method for forming a leading edge shield according to an embodiment of the invention; and 
         FIGS. 8A-8F  illustrate one embodiment of a method for forming the main pole in addition to the write pole according to an embodiment of the invention. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
     DETAILED DESCRIPTION 
     In the following, reference is made to embodiments of the invention. However, it should be understood that the invention is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the invention. Furthermore, although embodiments of the invention may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the invention. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the invention” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). 
     Embodiments of the invention are generally related to leading edge shields and magnetic write heads, and more specifically to methods for fabrication of leading edge shields and tapered magnetic poles. A magnetic pole may have a plurality of tapered surfaces at or near an air bearing surface (ABS), wherein a thickness of the write pole increases in a direction away from the ABS. 
     Referring now to  FIG. 1 , there is shown a disk drive  100  embodying this invention. As shown in  FIG. 1 , at least one rotatable magnetic disk  112  is supported on a spindle  114  and rotated by a disk drive motor  118 . The magnetic recording on each disk is in the form of annular patterns of concentric data tracks (not shown) on the magnetic disk  112 . 
     At least one slider  113  is positioned near the magnetic disk  112 , each slider  113  supporting one or more magnetic head assemblies  121 . As the magnetic disk rotates, the slider  113  moves radially in and out over the disk surface  122  so that the magnetic head assembly  121  may access different tracks of the magnetic disk where desired data are written. Each slider  113  is attached to an actuator arm  119  by way of a suspension  115 . The suspension  115  provides a slight spring force which biases slider  113  against the disk surface  122 . Each actuator arm  119  is attached to an actuator means  127 . The actuator means  127  as shown in  FIG. 1  may be a voice coil motor (VCM). The VCM comprises a coil movable within a fixed magnetic field, the direction and speed of the coil movements being controlled by the motor current signals supplied by controller  129 . 
     During operation of the disk storage system, the rotation of the magnetic disk  112  generates an air bearing between the slider  113  and the disk surface  122  which exerts an upward force or lift on the slider. The air bearing thus counter-balances the slight spring force of suspension  115  and supports slider  113  off and slightly above the disk surface by a small, substantially constant spacing during normal operation. 
     The various components of the disk storage system are controlled in operation by control signals generated by control unit  129 , such as access control signals and internal clock signals. Typically, the control unit  129  comprises logic control circuits, storage means and a microprocessor. The control unit  129  generates control signals to control various system operations such as drive motor control signals on line  123  and head position and seek control signals on line  128 . The control signals on line  128  provide the desired current profiles to optimally move and position slider  113  to the desired data track on disk  112 . Write and read signals are communicated to and from write and read heads  121  by way of recording channel  125 . 
     With reference to  FIG. 2 , the orientation of the magnetic head  121  in a slider  113  can be seen in more detail.  FIG. 2  is an ABS view of the slider  113 , and as can be seen the magnetic head including an inductive write head and a read sensor, is located at a trailing edge of the slider. The above description of a typical magnetic disk storage system and the accompanying illustration of  FIG. 1  are for representation purposes only. It should be apparent that disk storage systems may contain a large number of disks and actuators, and each actuator may support a number of sliders. 
     With reference now to  FIG. 3 , the invention can be embodied in a magnetic head  302  having a tapered write pole and a tapered leading edge. A non-magnetic bump may also be included in the embodiment as shown in  FIG. 3 . The magnetic write head  302  includes a magnetic write pole  304  and a magnetic return pole  306 . A magnetic back gap layer  308  and magnetic shaping layer  310  magnetically connect the return pole  306  with the write pole  304  at a location removed from an air bearing surface ABS. The magnetic write pole is further defined by a leading edge shield  307  and a leading edge taper  305 . 
     An electrically conductive, non-magnetic write coil  318  passes between the write pole  304  and the return pole  306  and may also pass above the write pole  304 . The write coil  318  can sit on top of a non-magnetic, electrically insulating material  322  and is also embedded in a non-magnetic, electrically insulating material  320  such as alumina and/or a hard baked photoresist. 
     During operation, an electrical current flowing through the coil  318  induces a magnetic field the results in a magnetic flux flowing through the write pole  304 . This causes a magnetic field to be emitted from the write pole  304  toward a magnetic medium such as the magnetic medium  122  shown in  FIG. 1 . This magnetic write field flows through the medium to return to the return pole  306  which has a sufficiently large cross section that it does not erase the magnetic bit written by the write pole  304 . 
     In order to increase the write field gradient (and thereby increase switching speed), the write head  302  also includes a magnetic leading shield  307  having a leading edge taper  305 . Additionally, in order to increase the write field gradient (and thereby increase switching speed), the write head  302  also includes a magnetic trailing shield  312 . This trailing shield  312  is separated from the write pole  304  by a trailing gap layer  332 . The write pole  304  may also be connected with a trailing return pole  316  that connects the trailing shield  312  with the back portion of the write head  302 , such as the back portion of the shaping layer  310 . 
     In some embodiments, the first width of the write head is between 20 nm and 150 nm and can taper away from the air bearing surface (ABS) at an angle α with respect to a plane parallel to the ABS surface. In one embodiment α is between about 30° and about 60°. 
     With reference now to  FIGS. 4A and 4B , a pole tip portion of a write head according to one embodiment of the invention is shown. As shown in  FIG. 4A , the write head  402  includes a write pole  404  that has a tapered trailing edge portion  406  (similar to the previously described embodiment), but which also has a tapered leading edge portion  408 . Having both tapered trailing and leading edges further optimizes the performance of the write head  402  by focusing magnetic flux to the tip of the write pole  404  while avoiding magnetic saturation of the write pole  404 . 
     The write head  402  has a leading edge shield  410 , a magnetic leading edge shield with a leading edge taper  411  as well as a trailing edge shield  412 , and a trailing magnetic shield. The leading edge shield  410  is separated from the write pole  404  by a leading gap distance  414 , and the trailing edge shield  412  is separated from the trailing edge of the write pole  404  by a trailing gap distance  416 , the leading gap distance  414  being significantly larger than the trailing gap distance  416  so as to prevent magnetic write field from being drawn toward the leading edge shield  410  during operation. The leading gap distance  414  is preferably at least twice the trailing gap distance  416 , and is more preferably about four times the trailing gap distance  416 . In one example, the leading gap distance  414  can be about 100 μm, whereas the trailing gap distance  416  can be about 25 μm. 
     The leading edge shield  410  is separated from the write pole  404  by first and second nonmagnetic layers  418 ,  420 . The first layer  418  can be constructed of a material such as chromium (Cr) or an alloy of nickel-chromium (NiCr). The second layer  420  can be constructed of a material such as ruthenium (Ru). 
     The write head also includes a non-magnetic spacer layer  422  which can be constructed of a material such as NiCr and can have a thickness of 50-200 μm. The non-magnetic spacer layer has a front edge  424  that is located a desired distance from the air bearing surface ABS. A non-magnetic bump  426 , constructed of a material such as alumina Al 2 O 3  is formed at the front edge of the non-magnetic spacer layer  422 , extending over a portion of the tapered trailing edge  406  of the write pole  404 . The non-magnetic spacer layer  422  and non-magnetic bump layer  426  provide additional spacing between the trailing edge shield  412  and the write pole  404  and also optimize the profile of this spacing by providing a smooth transition to this additional spacing. 
     The write head also includes a non-magnetic trailing gap layer  428  that separates the trailing edge shield  412  from the write pole  404  and which may also extend over the non-magnetic bump  426  and non-magnetic spacer layer  422 . The nonmagnetic trailing gap layer can be constructed of a material such as Ruthenium. In addition, non-magnetic, electrically insulating fill layers  430  may be provided behind the shields  410 ,  412 , although structures could be included in these regions as well. Also, a high magnetic moment seed layer  432  such as cobalt-iron (CoFe) may be included at the bottom of the trailing edge shield  412  to improve the performance of the trailing shield. 
       FIG. 4B  shows the write head  402  as viewed from the air bearing surface. As can be seen in  FIG. 4B , the trailing edge shield  412  extends downward beyond the sides of the write pole to form side shielding portions  452 ,  454 . For this reason, the trailing edge shield  412  can also be referred to as a “wrap-around” shield. Write head also includes non-magnetic insulating side fill layers  456 ,  458  that (for reasons that will become apparent below) are preferably constructed of a reaction ion etchable (RIEable) material such as SiO 2  or alumina. It also can be seen, that the non-magnetic side fill layers have substantially vertical outer sides, and that the layer  420  discussed above with reference to  FIG. 4A , also extends up the sides of the write head (also for reasons that will become apparent below). The thickness of the layers  420 ,  456 ,  428 ,  432  define the side gap distance  460 . 
     It can be seen in  FIG. 4B , that the layers  418  and  428  extend between the trailing edge shield  412  and the leading edge shield  410  so that the shields  412 ,  410  do not contact one another. In another embodiment of the invention, the layers  418  and  428  terminate at some point away from the write pole  404  so that the trailing edge shield  412  and leading edge shield  410  make magnetic contact at regions beyond the layers  418 , 428 . This embodiment can improve the performance of the trailing edge shield  412  by improving the flow of magnetic flux from the trailing edge shield  412 . 
       FIGS. 5A through 8G  describe embodiments of methods for manufacturing a magnetic write head according to the various embodiments described above with reference to  FIG. 3  and  FIGS. 4A-4B . 
       FIGS. 5A-5G  illustrate exemplary steps performed during fabrication of a leading edge taper of a write pole according to an embodiment of the invention. 
     As illustrated in  FIG. 5A , in one embodiment, fabrication of the structure may begin by providing a substrate material  500 . The substrate material  500  may be composed of a non-magnetic material, such as aluminum oxide (Al 2 O 3 ), also known as “alumina”. While not shown in the Figures, the substrate material  500  may include one or more other components of a magnetic head, e.g., a read head and one or more components of a write head already formed therein. Additionally, while not shown, the substrate material  500  may include a reaction ion etchable stop layer ( 310  above) disposed therein to form the bottom of any feature definition. Substrate material  500  may correspond to insulating material  320  of  FIG. 3 . In an alternative embodiment, the substrate material  500  may be a magnetic material as described herein. 
     A layer of material  510  that is resistant to reactive ion etching (RIE), a RIE stop layer, is deposited over the substrate. The RIE stop layer  510  can be a non-magnetic material such as tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), chromium (Cr), an alloy of nickel and chromium (NiCr), ruthenium (Ru), and combinations thereof, or laminated layers of these materials. 
     A fill layer  520  is deposited over the material layer  510 . The fill layer  520  may be a reactive ion etchable (RIEable) material, for example, alumina (Al 2 O 3 ), silicon dioxide (SiO 2 ), silicon nitride, and is deposited at least as thick as the desired thickness of a desired write pole thickness, as will become apparent below. 
     A feature definition  535  may be formed in the reactive ion etchable material (RIEable) of the fill layer  520  by a reactive ion etching (RIE) process, such as ion beam etching (IBE). The reactive ion etching (RIE) process is preferably performed at one or more angles relative to normal to form the fill layer  520  with the feature definition  535  having tapered side walls  537 . The one or more angles are from 10° to 60° relative to normal and are angled outward from the bottom of the feature definition to the top of the feature definition. Such a structure provides for a tapered structure from the surface into the material  520 , which can form a trapezoidal shape. 
     A non-magnetic material  530 , which may be a polishing stop material as described in  FIGS. 6A-6E , may be deposited by a conformal deposition process such as atomic layer deposition. This non-magnetic material  530  may be a non-magnetic material including tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), chromium (Cr), an alloy of nickel and chromium (NiCr), ruthenium (Ru), and combinations thereof, or laminated layers of these materials, and may be deposited to a sufficient thickness to advantageously reduce the width of the trench in order to shrink the track width of the yet to be formed write pole. 
     Then, a magnetic material  540 , such as cobalt-iron (CoFe) or cobalt-nickel-iron (CoNiFe), may be deposited, such as by electroplating, into the feature definition  535  formed in the fill layer  520 . The magnetic material  540  forms the leading edge shield material of the structure for a later main pole structure. A chemical mechanical polishing (CMP) process may be performed to planarize the magnetic layer  540 , leaving a structure as shown in  FIG. 5A , with a write pole material  540  in the feature definition  535 . An ion milling may then also be performed to remove portions of the non-magnetic layer  535  that may extend over the fill layer  520 . 
     Referring to  FIG. 5B , a magnetic material  550 , which will be a lead edge taper material, is then conformally deposited, such as by a sputtering process, on the planarized surface of the fill layer  520 , non-magnetic material  530 , and magnetic material  540 . The magnetic material  550  is a metal alloy selected from the group of nickel-iron (NiFe), cobalt-iron (CoFe), cobalt-nickel-iron (CoNiFe), and combinations thereof. The magnetic material  550  may the same material or a different material from the magnetic layer  540 . The magnetic material  550  may be deposited by a sputtering process, and may be deposited to a thickness from about 500 Å to about 1500 Å, for example about 1100 Å. A photoresist/resist material  560  is then deposited and patterned on the magnetic material  550 . 
     Referring to  FIG. 5C , an ion milling process or a reactive ion etch process, such as a ion beam etching (IBE) process, may be performed to remove portions of the magnetic layer  550  exposed by the patterned photoresist/resist material  560 . The ion milling is performed to remove a portion of the magnetic material layer  550  at a preferred angle, thereby allowing the formation of a tapered surface  555  on the magnetic material layer  550 . Additionally, the magnetic layer may be ion milled to provide for the tapered material having the end of the taper portions be within the horizontal surface bounds of the underlying magnetic material  540  as shown in  FIG. 5C . In one embodiment, the magnetic material layer  550  has a tapered portions coupled only to the underlying magnetic material  540  on the substrate surface. 
     The ion milling is performed at one or more angles relative to normal, such that shadowing from the patterned photoresist/resist layer  560  causes the tapered surface to form an angle from 10 to 60 degrees, such as from 20 to 40 degrees, for example, about 30 degrees with respect to a plane that is parallel with the surfaces of the as deposited layers. The tapered structure forms the leading edge taper structure. As shown on the Figures, the leading edge taper may have more than one tapered side, and each side may have the same or substantially the same angles. If any non-magnetic material  550  was disposed on the surface of the layers (not shown), the non-magnetic material  530  may be removed with the ion milling process. 
     Referring to  FIG. 5D , the patterned photoresist/resist material  560  is then removed from the magnetic layer  550 . The patterned photoresist/resist material  560  may be removed by a liftoff or ashing process. 
     Referring to  FIG. 5E , a non-magnetic layer  570  is conformally deposited over the magnetic material layer  550  and the exposed surfaces of the fill layer  520 , non-magnetic material  530 , and magnetic material  540 . The non-magnetic layer  570  may be a reactive ion etching (RIE) stop layer and may be a non-magnetic material including tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), chromium (Cr), an alloy of nickel and chromium (NiCr) ruthenium (Ru), and combinations thereof, or laminated layers of these materials. The non-magnetic layer  570  may be deposited to a thickness of 40-60 μm or about 50 μm. 
     Referring to  FIG. 5F , a bulk layer  580  of a non-magnetic material, such as alumina, may be deposited over the conformal non-magnetic RIE stop layer  570 . 
     The bulk layer  580  (and optionally, the non-magnetic RIE stop layer  570 ) may then be planarized. The substrate material  500  and bulk layer  580  may be of the same material, and may comprises a material selected from the group of alumina (Al 2 O 3 ), silicon oxide, silicon nitride, an combinations thereof, amongst other dielectric materials. The formed structure may then provide for main pole processing. 
       FIG. 5G , illustrates the layering structure after the air bearing surface process which shows the leading edge shield portion  340  and the leading edge taper portion  355  containing the ABS allowing for the formation of the write pole with a leading tapered surface as shown in  FIG. 3 . 
     The structure formed in  FIG. 5A , may be formed by several different processes, of which two embodiments can be described as follows with reference to  FIGS. 6A-6E  and  FIGS. 7A-7E , respectively. 
     One manner to form the leading edge shield comprises depositing a seed layer over a substrate. The seed layer may be deposited by conventional deposition techniques such as electroplating or sputtering. A photoresist mask is then formed which leaves select areas of the seed layer exposed. The magnetic material is then deposited onto the exposed areas of the seed layer. The mask may then be removed, as well as the exposed seed layer that underlies the mask. The removal may occur utilizing ion beam milling to expose the underlying substrate. A layer of Al 2 O 3  may then be formed over the exposed surfaces which include portions of the substrate and the magnetic material. The Al 2 O 3  may then be planarized back using a CMP process to expose the magnetic material, which is also polished at least partially. The process flow is simple, but can not achieve the desired uniformity for the preferred 0.1 to 0.3 micron thickness of the leading edge shield and hence, has no manufacturability. In contrast, the process flow discussed below in regards to  FIGS. 6A-6E  includes depositing a CMP stop layer, photo pattern, etch, refill, CMP and light mill to provide a better leading edge shield thickness mean and uniformity control. The process flow discussed below in regards to  FIGS. 7A-7E  involves etching, refilling with a stop layer and leading edge shield material, then CMP and light ion beam etching. The process flow for  FIGS. 6A-6E  will leave no process signature of the CMP stop layer while the process flow for  FIGS. 7A-7E  will have the process signature of a CMP stop layer. The leading edge shield, for both  FIGS. 6A-6E  and  FIGS. 7A-7E  are fabricated after the reader is completed. The leading edge shield is fabricated with a throat height length ranging from about 0.2 microns to about 0.3 microns. The thickness of the leading edge shield is between about 0.1 microns and about 0.3 microns. The magnetic material for the leading edge shield may comprise soft magnetic materials such as NiFe, CoNiFe, and CoFe. 
     Referring to  FIGS. 6A-6E , the structure of  FIG. 5A  may be formed by first providing a substrate material  600 . The substrate material  600  may be composed of a non-magnetic material, such as aluminum oxide (Al 2 O 3 ), also know as “alumina”. While not shown in the Figures, the substrate material  600  may include one or more other components of a magnetic head, e.g., a read head and one or more components of a write head already formed therein. Additionally, while not shown, the substrate material  600  may include a reaction ion etchable layer stop layer ( 310  above) disposed therein to form the bottom of any feature definition. Substrate material  600  may correspond to insulating material  320  of  FIG. 3 . In an alternative embodiment, the substrate material  600  may be a magnetic material as described herein. 
     A layer of material  610  that is resistant to chemical mechanical polishing (CMP), a CMP resistance material (or CMP stop layer), is deposited over the substrate. The CMP resistance material  610  may be a material selected from the group consisting of iridium (Ir), ruthenium (Ru), Rhodium (Rh), tantalum (Ta), and combinations thereof, and is preferably a non-magnetic material. The CMP resistance material  610  may be deposited to a thickness from 100 Å to 500 Å. A photoresist material  620  is then deposited and patterned on the CMP resistance material  610 . 
     Referring to  FIG. 6B , a feature definition  625  may be formed in the substrate material  600  by reactive ion etching (RIE) or ion beam etching (IBE) the exposed CMP resistance material  610  and the underlying substrate material  600 . The reactive ion etch process is preferably performed at one or more angles relative to normal to form the feature definition  625  having tapered side walls  627 . The one or more angles are from 10° to 60° relative to normal and are angled outward from the bottom of the feature definition to the top of the feature definition. The photoresist/resist material  620  is also removed after the etching process, such as by a liftoff or ashing process. The feature definition is formed having a depth (or thickness) from 0.1 μm to 0.3 μm. 
     A magnetic material  630 , such as cobalt-iron (CoFe) of cobalt-nickel-iron (CoNiFe), may be deposited on the CMP stop layer  610  and into the feature definition  625  formed in the substrate material  600  as shown in  FIG. 6C . The magnetic material  630  may be deposited by a plating process, such as electroplating, or a physical vapor deposition (sputtering) process. 
     A planarization process, such as by a chemical mechanical polishing (CMP) process, may be performed to remove the magnetic layer  630  deposited over the CMP stop layer  610  and planarize the magnetic layer  630  to the CMP resistance material  610 , leaving a structure shown in  FIG. 6D , which is in essence a leading edge shield formed in the feature definition  625 . 
     An ion milling, such as by a light ion beam etching process (IBE) or sputter etching process may then also be performed to remove portions of the CMP resistance material  610  still remaining after the planarization process as shown in  FIG. 6E . The ion milling can be skipped if a LET process is used further down the line. The ion milling may remove between about 100 Angstroms and about 500 Angstroms. 
     Referring to  FIGS. 7A-7E , the structure may be formed by first providing a substrate material  700 . The substrate material  700  may be composed of a non-magnetic material, such as Aluminum Oxide (Al 2 O 3 ), also know as “alumina”. While not shown in the figures, the substrate material  700  may include one or more other components of a magnetic head, e.g., a read head and one or more components of a write head already formed therein. A photoresist/resist material  720  is then deposited and patterned on the substrate material  700 . Additionally, while not shown, the substrate material  700  may include a reaction ion etchable layer stop layer ( 310  above) disposed therein to form the bottom of any feature definition. Substrate material  700  may correspond to insulating material  320  of  FIG. 3 . In an alternative embodiment, the substrate material  700  may be a magnetic material as described herein. 
     Referring to  FIG. 7B , a feature definition  725  may be formed in the substrate material  700  by reactive ion etching (RIE) or ion beam etching (IBM) the exposed substrate material  700 . The reactive ion etch process is preferably performed at one or more angles relative to normal to form the feature definition  725  having tapered side walls  727 . The one or more angles are from 10° to 60° relative to normal and are angled outward from the bottom of the feature definition  725  to the top of the feature definition  725 . The feature definition  725  is formed having a depth (or thickness) from 0.1 μm to 0.3 μm. The photoresist/resist material  720  is also removed after the etching process, such as by a liftoff or ashing process. 
     Referring to  FIG. 7C , a layer of material that is resistant to chemical mechanical polishing (CMP), a CMP resistance material  710  (or CMP stop layer), is deposited over the substrate and in the feature definition conformally. The CMP resistance material  710  may be a material selected from the group consisting of iridium (Ir), ruthenium (Ru), Rhodium (Rh), tantalum (Ta), and combinations thereof, and is preferably a non-magnetic material. The CMP resistance material  710  may be sputter deposited to a thickness from 100 Å to 500 Å. 
     A magnetic material  730 , such as cobalt-iron (CoFe) or cobalt-nickel-iron (CoNiFe), may be deposited onto the CMP resistance material  710  and into the feature definition  725  formed in the substrate material  700  as shown in  FIG. 7C . The magnetic material  730  may be deposited by a plating process, such as electroplating, or a physical vapor deposition (sputtering) process. 
     A planarization process, such as by a chemical mechanical polishing (CMP) process, may be performed to remove and planarize the magnetic layer  730  to the CMP resistance material  710 , leaving a structure shown in  FIG. 7D , which is in essence a leading edge shield formed in the feature definition  725 . 
     An ion milling, such as by a light ion beam etching process (IBE) may then also be performed to remove portions of the CMP resistance material  710  still remaining after the planarization process as shown in  FIG. 7E . 
     The process flows shown in  FIGS. 6A-6E  and  7 A- 7 E are comparable. The process flow in  FIGS. 6A-6E  will leave no process signature of a CMP stop layer while the process flow in  FIGS. 7A-7E  will have a process signature of a CMP stop layer. A Cr/NiCr RIE stop layer may be deposited on the leading edge shield after the leading edge shield is completed to make a perpendicular write head with a four side wrap-around shield but without the leading edge taper. After the leading edge shield is done, the leading edge taper can also be built upon the leading edge shield so that the perpendicular write head will have both a leading edge shield and a leading edge taper. 
     Referring to  FIGS. 8A-8F , one embodiment of forming a main pole on the write material is as follows. 
     The non-magnetic fill material  380  as shown in  FIG. 5F  is removed. An optional non-magnetic step layer, preferably constructed of NiCr may be deposited over the non-magnetic layer  570  (non-magnetic reactive ion etching (RIE) stop layer) and the leading edge taper material  555 . The pole material  810  may then be deposited and planarized. The pole material  810  may comprise a magnetic material as described herein. 
     A non-magnetic step layer  820 , preferably constructed of NiCr is deposited over the pole material  810 . A mask layer and/or a photoresist/resist layer (not shown) are deposited and patterned over the non-magnetic step layer  820  and the pole material  810 . The non-magnetic step layer  820  and the pole material  810  are then etched and patterned by an ion milling process to form an upper tapered surface  825 . Any mask or photoresist/resist material are then removed to provide the structure as shown in  FIG. 8B . 
     A layer of non-magnetic material  830 , such as alumina, is deposited by a conformal deposition process such as atomic layer deposition or chemical vapor deposition as shown in  FIG. 8C . 
     Then, an ion milling is performed to preferentially remove horizontally disposed portions of the alumina layer, leaving an alumina bump  835  at the front edge of the non-magnetic step layer  820 . A layer of non-magnetic material  840  is deposited to a thickness to define a desired trailing gap thickness as shown in  FIG. 8D . The trailing gap layer  840  can be constructed of ruthenium and other non-magnetic materials. A non-magnetic, electrically insulating material  860 , such as alumina  860 , may then be deposited on the trailing gap layer  840 . 
     Referring to  FIG. 8E , the non-magnetic, electrically insulating material  860  may then be etched to expose a portion of the trailing gap layer  840  formed from the air bearing surface to a portion along the substantially horizontal portion of the trailing gap layer  840 . An optional high magnetic moment seed layer  850  may be deposited and patterned on the exposed trailing gap layer  840 . A trailing shield  870  may be deposited on the high magnetic seed layer  850 . The high magnetic moment seed layer  850  may be provided at the leading edge of the trailing shield  870  ( 312 ) to maximize the performance of the trailing shield. 
     Additional structures, such as a trailing return pole, additional non-magnetic, electrically insulating material, and coils may be formed on the structure to form the head structure. The structure may then be processed to form an air bearing surface, as shown by line ABS formed through the structure in  FIG. 8F  to form the structure as shown in  FIG. 3 . 
     While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.