Abstract:
A method and system for manufacturing a perpendicular magnetic recording head is disclosed. The method and system include providing a chemical mechanical planarization (CMP) uniformity structure having an aperture therein and forming a perpendicular magnetic recording pole within the aperture. The CMP uniformity structure may include a CMP barrier layer. The method and system further include fabricating an insulator after formation of the perpendicular magnetic recording pole and performing a CMP to remove a portion of the insulator, expose a portion of the perpendicular magnetic recording pole and planarize an exposed surface of the perpendicular magnetic recording head.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 10/936,921, filed Sep. 8, 2004, herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to magnetic recording technology, and more particularly to a method and system for fabricating a perpendicular recording head. 
     BACKGROUND OF THE INVENTION 
       FIG. 1  depicts a portion of conventional perpendicular magnetic recording (PMR) head  10  as viewed from the air-bearing surface (ABS). The conventional PMR head  10  includes a conventional pole  16  and a top shield  24  separated by a write gap  20 . Note that the top shield  24  also acts as pole during writing using the conventional PMR head  10 . The conventional pole  16  and the top shield  24  are surrounded by insulating layers  18  and  22 . The conventional pole  16  resides on a seed layer  12  and has sidewalls  14 . 
     In conventional applications, the height of the conventional pole  16  is typically less than approximately three-tenths micrometer. The conventional pole  16  also has a negative angle such that the top of the conventional pole  16  is wider than the bottom of the conventional pole  16 . Stated differently, the angle θ of the sidewalls is less than 90 degrees in the conventional pole  16  of  FIG. 1 . A pole having this height and shape is desirable for use in PMR applications. 
       FIG. 2  depicts a conventional method  50  for forming the conventional PMR head  10 . A seed layer  12  for the conventional pole  16  is deposited and the pattern for the conventional pole  16  formed, via steps  52  and  54 , respectively. The material for the conventional pole  16  is plated, via step  56 . The remaining seed layer around the conventional pole  16  is removed, via step  58 . The conventional pole  16  is then trimmed, via step  60 . Consequently, the width of the conventional pole  16  and the negative angle are set in step  60 . The insulator  18  is deposited around the conventional pole  16 , via step  62 . A chemical mechanical planarization (CMP) is performed to planarize the surface and expose the conventional pole  16 , via step  64 . The surface is planarized in order to allow subsequent processing to be performed as desired. The write gap  20  is provided, via step  66 . The top shield  24  that also acts as the pole is deposited and patterned in step  68 . Finally, the region around the top shield  24  is insulated, via step  70 . 
     Although the conventional method  50  can be used to form a conventional PMR head  10 , the variation in the CMP process used in exposing the conventional pole  16  in step  64  has a relatively large vertical variation. In particular, the three-sigma variation in the CMP is on the order of three-tenths micrometer. The variation in the CMP process is thus on the order of the height of the conventional pole  16 . As a result, the height of the conventional pole  16  may be extremely difficult to control and fabrication of suitable conventional PMR heads  10  difficult to repeat. Manufacturing of conventional PMR heads  10  may, therefore, have a very low yield. 
     Accordingly, what is needed is an improved, repeatable method for fabricating a PMR head. The present invention addresses such a need. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a method and system for manufacturing a perpendicular magnetic recording head. The method and system comprise providing a CMP uniformity structure having an aperture therein and forming a perpendicular magnetic recording pole within the aperture. The method and system further include fabricating an insulator after formation of the perpendicular magnetic recording pole and performing a CMP to remove a portion of the insulator, expose a portion of the perpendicular magnetic recording pole and planarize an exposed surface of the perpendicular magnetic recording head. 
     According to the method and system disclosed herein, the present invention allows perpendicular recording poles to be repeatably fabricated using CMP in processing. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is diagram depicting a conventional perpendicular magnetic recording pole. 
         FIG. 2  is a flow chart depicting a conventional method for fabricating a perpendicular magnetic recording pole. 
         FIGS. 3A-3E  depict a perpendicular magnetic recording head formed in accordance with an exemplary embodiment of the present invention. 
         FIG. 4  is a high-level flow chart depicting one embodiment of a method in accordance with the present invention for fabricating a perpendicular magnetic recording pole in accordance with an exemplary embodiment of the present invention. 
         FIG. 5  is a flow chart depicting a method for providing a perpendicular magnetic recording pole in accordance with an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 3A-3E  depict one embodiment of a PMR head  100  formed during fabrication in accordance with an exemplary embodiment of the present invention during fabrication. To enhance clarity  FIGS. 3A-3E  are not drawn to scale.  FIG. 3A  depicts a preferred embodiment of the CMP uniformity structure  110  used in forming a PMR (not shown in  FIG. 3A ) pole for the PMR head  100 . The CMP uniformity structure  110  includes an aperture  116  therein. The PMR pole for the PMR head  100  is formed in the aperture  116 . The CMP uniformity structure  110  used to reduce the variations in the CMP process, as described below. To form the CMP uniformity structure  110 , its layer of the CMP uniformity structure  110  are deposited and patterned, generally using photolithography. 
     In a preferred embodiment, depicted in  FIG. 3A , the CMP uniformity structure  110  includes a CMP support structure  112  and a CMP barrier layer  114 . The CMP support structure  112  is insulating and, in a preferred embodiment, includes material(s) such as Al 2 O 3 , SiO 2 , SiN, and/or diamond-like carbon. In a preferred embodiment, the CMP support structure  112  has a thickness that is at least the desired final thickness of the PMR pole being formed. In one embodiment, the CMP support structure  112  has a thickness of 0.1-0.4 μm. The CMP barrier layer  114  includes at least one of Ta, Ti, TiN, TaN, diamond-like carbon. Also in a preferred embodiment, CMP barrier layer  114  is configured to have a removal rate of at least approximately five to ten times slower than the removal rate of an insulator used to insulate the pole during a CMP designed to remove the insulator. 
       FIG. 3B  depicts the PMR head  100  after the PMR pole  130  has been formed. Thus, a seed layer  120  and the PMR pole  130  are shown. In a preferred embodiment, the PMR pole  130  is formed by providing a pattern (not shown) having an opening in which the PMR pole  130  has been plated. Note that layers  132 , which include the excess pole material that has been plated when the PMR pole  130  was plated, are shown. However, these layers  132  are subsequently removed. The top  136 , bottom  134 , and sides  131  and  133  of the PMR pole  130  are also specifically indicated. 
       FIG. 3C  depicts the PMR head  100  after the PMR pole  130  has been trimmed, portions of the seed layer  120  around the PMR pole  130  have been removed, and an insulator  140  has been deposited. The critical dimensions and the negative angle for the PMR pole  130  have been set by the pole trim. The negative angle of the PMR pole  130  can be seen in that the top  134  of the PMR pole  130  is wider than the bottom  136  of the PMR pole  130 . Thus, the left side  131  of the PMR pole  130  is at an angle, Θ 1 , counterclockwise from a vertical dropped down from the upper left corner of the PMR pole  130 . Similarly, the right side  133  of the PMR pole  230  is at an angle, Θ 2 , clockwise from a vertical dropped down from the upper right corner of the PMR pole  130 . Thus, the PMR pole  130  has a negative angle. As can also be seen in  FIG. 3C , the insulator  140  fills in the gaps between the PMR pole  130  and the CMP support structure  112  and the CMP barrier layer  114 . 
     Note that the aperture  116  of the CMP uniformity structure  110  has a diameter that is selected based on several considerations. The aperture  116  is sufficiently wide such that the CMP uniformity structure  110  does not adversely affect any photolithography performed for the PMR pole. The width of the aperture  116  is also selected to allow for the pole trim that sets the critical dimensions of the PMR pole  130 . The pole trim is preferably performed using argon ions aimed at an angle from normal to the surface of the PMR pole  130 . Consequently, the aperture  116  is also wide enough such that the ions do not impact the CMP barrier layer  114  or the CMP support structure  112  in lieu of the PMR pole  130 . On the other hand, the aperture  116  is narrow enough such that the CMP uniformity structure  110  allows the uniformity of the CMP step, discussed below, to be improved to be better than the thickness of the PMR pole  130 . Thus, in a preferred embodiment, the width of the aperture  116  is on the order of ten times the width of the PMR pole  130 . This is because the sides  118  of the aperture  116  are desired to be a distance away from the edges  131  and  133  of the PMR pole  130  that is approximately five times the width of the PMR pole  130 . Consequently, in a preferred embodiment, the width of the aperture  116  is approximately one hundred microns. 
       FIG. 3D  depicts the PMR head  100  after completion of a CMP step that is engineered to remove the insulator  140 . Thus, the excess insulator  140  has been removed, the PMR pole  130  exposed, and the exposed surface planarized. Because of the CMP uniformity structure  110 , the variation in height of the top, exposed surface of the PMR head  100  is reduced. In addition, in the embodiment shown, the CMP barrier layer  114  has been removed. However, nothing prevents at least a portion of the CMP barrier layer  114  from remaining as part of the PMR head  100 . In a preferred embodiment, the CMP barrier layer  114  is configured such that the CMP discussed above the insulator  140  at least five to ten times more rapidly than the CMP barrier layer  214 . Thus, the removal rate of the insulator  140  is approximately five to ten times higher than the removal rate of the CMP barrier layer  114 . In addition, because of the CMP uniformity structure  110 , resulting surface has less variation in height than a conventional structure. The three sigma variation is less than the height of the PMR pole  130 . In one embodiment, the three sigma variation is on the order of 0.1 μm. Once the CMP has been completed, any remaining CMP barrier layer  14  may be removed, preferably using a reactive ion etch. 
       FIG. 3E  depicts the PMR  100  after completion. Thus, the write gap  150 , top shield  160 , and insulator  170  are depicted. 
     Thus, the PMR pole  130  may be more reliably fabricated and a more planar surface provided for subsequent steps in manufacturing the PMR head. Moreover, the CMP may be more easily and closely controlled by measuring the thickness of the insulator on top of the CMP barrier layer. Consequently, the PMR head  100  may be more reliably fabricated at higher dimensions 
       FIG. 4  depicts a high-level flow chart of a method  200  for providing a PMR head in accordance with an exemplary embodiment of the present invention. The method  200  is described in the context of forming a single PMR head  200 . However, one of ordinary skill in the art will readily recognize that typically multiple PMR heads  100  are fabricated simultaneously on a substrate. One of ordinary skill in the art will also readily recognize that other and/or additional steps not inconsistent with the present invention may be included in the method  200 . Further, for clarity, the method  200  is described in the context of PMR heads  100 . However, nothing prevents the use of the method  200  with another PMR head (not shown). 
     The CMP uniformity structure  110  is fabricated, via step  202 . Step  102  preferably includes depositing the layer(s) of the CMP uniformity structure and patterning the CMP uniformity structure, generally using photolithography. A PMR pole  139  is formed, via step  204 . Step  204  includes depositing a seed layer, performing photolithography to provide a pattern for the PMR pole, electroplating the PMR pole, removing excess seed layer, and trimming the pole. An insulating layer  140  is fabricated, preferably by sputtering Al 2 O 3 , via step  206 . Thus, the PMR pole  130  is insulated. The insulator  140  preferably fills the aperture around the PMR pole  130 . A CMP is then performed, via step  208 . The CMP is configured to remove the insulator, thereby exposing the PMR pole and planarizing the surface. The CMP uniformity  110  structure provided in step  202  is configured to improve the uniformity of the CMP performed in step  208  and provide a more planar surface. In addition, the CMP barrier layer  114 , if used, is significantly more resistant to removal by the CMP in step  108  than the insulator. Fabrication of the PMR head can then be completed. 
     Using the method  200 , the PMR pole  130  may be provided. Because of the use of the CMP uniformity structure  110 , the CMP performed in step  208  results in a more planar surface. In particular, a three sigma variation in height of the PMR head of below 0.1 μm may be achieved. Thus, the PMR pole may be more reliably fabricated and a more planar surface provided for subsequent steps in manufacturing the PMR head. Moreover, the CMP performed in the method  200  may be more easily and closely controlled by measuring the thickness of the insulator on top of the CMP barrier layer. Consequently, the method  100  can be used in fabricating a PMR head. 
       FIG. 5  depicts a more-detailed flow chart of a method  250  for providing a PMR head in accordance with an exemplary embodiment of the present invention. The method  250  is described in the context of the PMR head  100 . Consequently, the method  250  is described in the context of the PMR head  100  depicted in  FIGS. 3A-3E . Referring to  FIGS. 3A-3E  and  FIG. 5 , the method  150  is also described in the context of forming a single PMR head  100 . However, one of ordinary skill in the art will readily recognize that typically multiple PMR heads  100  are fabricated simultaneously on a substrate. One of ordinary skill in the art will also readily recognize that other and/or additional steps not inconsistent with the present invention may be included in the method  250 . 
     The method  250  commences with formation of the CMP uniformity structure  110 , via step  252 . Step  252  preferably includes depositing the layer(s) of the CMP uniformity structure  110  and patterning the CMP uniformity structure  110 , generally using photolithography. In a preferred embodiment, step  202  include depositing the insulating layer(s) for the CMP support structure  112 , depositing the layer(s) for the CMP barrier layer  114 , and providing the aperture  116  and any other features in the CMP uniformity structure  110  using photolithography. 
     The PMR pole  130  is formed in steps  254 - 264  of the method  250 . Thus, a seed  120  is provided, via step  254 . A pattern for the PMR pole  130  is provided, via step  256 . The pattern includes an opening (not shown) in which the PMR pole can be plated. The PMR pole  130  is then plated, via step  258 . 
     The seed layer  120  is removed from the region around the PMR pole  130 , via step  260 . A field etch and pole trim are performed, via steps  262  and  264 , respectively. The critical dimensions of the PMR pole  130  are set and the negative angle for the PMR pole  130  are provided by the pole trim performed in step  264 . 
     An insulator is provided to insulate the PMR pole  130 , via step  266 . The insulator is preferably Al 2 O 3  that is sputtered. 
     The CMP is performed to remove the excess portion of the insulator  140  and expose the PMR pole  130 , via step  268 . The CMP performed in step  168  is thus engineered to remove the insulator  140  and planarize the remaining exposed surface. In a preferred embodiment, therefore, the CMP performed in step  268  is designed to remove Al 2 O 3 . In a preferred embodiment, the CMP barrier layer  114  is configured such that the CMP performed in step  268  removes the insulator  140  at least five to ten times more rapidly than the CMP barrier layer  114 . Thus, the removal rate of the insulator  140  in the CMP step  268  is approximately five to ten times higher than the removal rate of the CMP barrier layer  114  during the CMP step  268 . 
     Fabrication of the PMR head  100  is completed, via step  272 . Step  272  thus preferably includes formation of a write gap, fabrication of a top shield including photolithography and deposition of a seed layer, providing another insulating layer that is preferably Al 2 O 3 , and performing a subsequent CMP. 
     Thus, the method  250  can be used to provide a PMR head. Because of the use of the CMP uniformity structure, the CMP performed in step  268  results in a more planar surface. In particular, a three sigma variation in height of the PMR head  100  of below 0.1 μm may be achieved. Thus, the PMR pole  130  may be more reliably fabricated and a more planar surface provided for subsequent steps in manufacturing the PMR head. Moreover, the CMP performed in the method  250  may be more easily and closely controlled by measuring the thickness of the insulator on top of the CMP barrier layer. Consequently, the method  250  provides a more reliable method for fabricating a PMR head.