Patent Publication Number: US-2018040341-A1

Title: Magnetic devices with variable overcoats

Description:
PRIORITY 
     This application claims priority to U.S. Provisional Application No. 61/740,514 entitled “MAGNETIC DEVICES HAVING VARIABLE OVERCOATS ON WRITER AND READER” having docket number 430.17293000 filed on Dec. 21, 2012, the disclosure of which is incorporated herein by reference thereto. 
    
    
     BACKGROUND 
     The heat assisted magnetic recording (HAMR) process can involve an environment that can be extremely corrosive because of the high temperature and exposure to corrosive chemistries. Furthermore, designs using close head-media spacing will experience more rapid wear of any narrow, protruded features such as write poles. Because of the harsh environment and the desire to protect some of the more delicate structures, for example the near field transducer (NFT) and the write pole for example, there remains a need for different types of overcoats. 
     SUMMARY 
     A magnetic device including: a magnetic reader; a magnetic writer; and a variable overcoat, the variable overcoat positioned over at least the magnetic reader and writer, the variable overcoat having an overcoat layer, the overcoat layer having a substantially constant thickness and material; and at least one disparate overcoat portion, the disparate overcoat portion having a different thickness, a different material, or both, than the overcoat layer. 
     A method includes depositing a first layer over the entire surface of a structure, the structure having a magnetic reader and a magnetic writer, wherein the magnetic reader and the magnetic writer are positioned adjacent to each other on a substrate; removing a portion of the first layer over at least the magnetic reader; and depositing a second layer over the entire surface of the first layer, wherein the first layer and the second layer make up a variable overcoat, the variable overcoat having a disparate overcoat region over the magnetic writer. 
     A method that includes depositing a first layer on the entire surface of a structure, the structure including a magnetic reader and a magnetic writer, wherein the magnetic reader and the magnetic writer are positioned adjacent to each other on a substrate; masking regions of the surface to form exposed and unexposed regions; depositing a second layer on the surface of the exposed and unexposed regions; and removing the unexposed regions and the second layer on the unexposed regions. 
     The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a pictorial representation of a data storage device in the form of a disc drive that can include a recording head constructed in accordance with an aspect of this disclosure. 
         FIG. 2  is a side elevation view of a recording head constructed in accordance with an aspect of the invention. 
         FIG. 3  is a schematic depiction of a device, looking from the air bearing surface (ABS). 
         FIG. 4A  is a schematic depiction of a device, looking from the air bearing surface (ABS), depicting a disparate overcoat region over the magnetic writer. 
         FIG. 4B  is a side view of a schematic depiction of a portion of the device of  FIG. 4A  from a cross track direction. 
         FIG. 5A  is a schematic depiction of a device, looking from the air bearing surface (ABS), depicting two disparate overcoat regions. 
         FIG. 5B  is a side view of a schematic depiction of a portion of the device of  FIG. 5A  from a cross track direction. 
         FIGS. 6A to 6E  depict cross sections of articles at various stages of completion for a disclosed method. 
         FIGS. 7A to 7D  depict cross sections of articles at various stages of completion for a disclosed method. 
         FIGS. 8A, 8B, and 8C  show optical microscopic images of devices having disclosed disparate overcoat regions. 
         FIGS. 9A to 9D  depict cross sections of articles at various stages of completion for a disclosed method. 
         FIGS. 10A to 10D  depict cross sections of articles at various stages of completion for a disclosed method. 
         FIGS. 11A, 11B, and 11C  are atomic force microscopy (AFM) images of an article at various stages of manufacture. 
         FIG. 12  is an illustration of an article that can be formed using various methods disclosed herein. 
     
    
    
     The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. 
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying set of drawings that form a part hereof and in which are shown by way of illustration several specific embodiments. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. 
     Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. 
     The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     “Include,” “including,” or like terms means encompassing but not limited to, that is, including and not exclusive. It should be noted that “top” and “bottom” (or other terms like “upper” and “lower”) are utilized strictly for relative descriptions and do not imply any overall orientation of the article in which the described element is located. 
     Disclosed devices can offer the advantage of providing more efficient transfer of energy from an energy source to the magnetic storage media to be heated, a smaller focal point at the point of heating, or some combination thereof. In some embodiments, disclosed devices can be used within other devices or systems, such as magnetic recording heads, more specifically, thermally or heat assisted magnetic recording (HAMR) heads, or disc drives that include such devices. 
     Disclosed herein are NFTs and devices that include such NFTs.  FIG. 1  is a pictorial representation of a data storage device in the form of a disc drive  10  that can utilize disclosed NFTs. The disc drive  10  includes a housing  12  (with the upper portion removed and the lower portion visible in this view) sized and configured to contain the various components of the disc drive. The disc drive  10  includes a spindle motor  14  for rotating at least one magnetic storage media  16  within the housing. At least one arm  18  is contained within the housing  12 , with each arm  18  having a first end  20  with a recording head or slider  22 , and a second end  24  pivotally mounted on a shaft by a bearing  26 . An actuator motor  28  is located at the arm&#39;s second end  24  for pivoting the arm  18  to position the recording head  22  over a desired sector or track  27  of the disc  16 . The actuator motor  28  is regulated by a controller, which is not shown in this view and is well-known in the art. The storage media may include, for example, continuous media or bit patterned media. 
     For heat assisted magnetic recording (HAMR), electromagnetic radiation, for example, visible, infrared or ultraviolet light is directed onto a surface of the data storage media to raise the temperature of a localized area of the media to facilitate switching of the magnetization of the area. Recent designs of HAMR recording heads include a thin film waveguide on a slider to guide light toward the storage media and a near field transducer to focus the light to a spot size smaller than the diffraction limit. While  FIG. 1  shows a disc drive, disclosed NFTs can be utilized in other devices that include a near field transducer. 
       FIG. 2  is a side elevation view of a recording head that may include a disclosed NFT; the recording head is positioned near a storage media. The recording head  30  includes a substrate  32 , a base coat  34  on the substrate, a bottom pole  36  on the base coat, and a top pole  38  that is magnetically coupled to the bottom pole through a yoke or pedestal  40 . A waveguide  42  is positioned between the top and bottom poles. The waveguide includes a core layer  44  and cladding layers  46  and  48  on opposite sides of the core layer. A mirror  50  is positioned adjacent to one of the cladding layers. The top pole is a two-piece pole that includes a first portion, or pole body  52 , having a first end  54  that is spaced from the air bearing surface  56 , and a second portion, or sloped pole piece  58 , extending from the first portion and tilted in a direction toward the bottom pole. The second portion is structured to include an end adjacent to the air bearing surface  56  of the recording head, with the end being closer to the waveguide than the first portion of the top pole. A planar coil  60  also extends between the top and bottom poles and around the pedestal. In this example, the top pole serves as a write pole and the bottom pole serves as a return pole. 
     An insulating material  62  separates the coil turns. In one example, the substrate can be AlTiC, the core layer can be Ta 2 O 5 , and the cladding layers (and other insulating layers) can be Al 2 O 3 . A top layer of insulating material  63  can be formed on the top pole. A heat sink  64  is positioned adjacent to the sloped pole piece  58 . The heat sink can be comprised of a non-magnetic material, such as for example Au. 
     As illustrated in  FIG. 2 , the recording head  30  includes a structure for heating the magnetic storage media  16  proximate to where the write pole  58  applies the magnetic write field H to the storage media  16 . In this example, the media  16  includes a substrate  68 , a heat sink layer  70 , a magnetic recording layer  72 , and a protective layer  74 . However, other types of media, such as bit patterned media can be used. A magnetic field H produced by current in the coil  60  is used to control the direction of magnetization of bits  76  in the recording layer of the media. 
     The storage media  16  is positioned adjacent to or under the recording head  30 . The waveguide  42  conducts light from a source  78  of electromagnetic radiation, which may be, for example, ultraviolet, infrared, or visible light. The source may be, for example, a laser diode, or other suitable laser light source for directing a light beam  80  toward the waveguide  42 . Specific exemplary types of light sources  78  can include, for example laser diodes, light emitting diodes (LEDs), edge emitting laser diodes (EELs), vertical cavity surface emitting lasers (VCSELs), and surface emitting diodes. In some embodiments, the light source can produce energy having a wavelength of 830 nm, for example. Various techniques that are known for coupling the light beam  80  into the waveguide  42  may be used. Once the light beam  80  is coupled into the waveguide  42 , the light propagates through the waveguide  42  toward a truncated end of the waveguide  42  that is formed adjacent the air bearing surface (ABS) of the recording head  30 . Light exits the end of the waveguide and heats a portion of the media, as the media moves relative to the recording head as shown by arrow  82 . Energy delivered by the NFT  84  is the primary means of heating the media. A near-field transducer (NFT)  84  is positioned in or adjacent to the waveguide and at or near the air bearing surface. The design may incorporate a heat sink made of a thermally conductive material integral to, or in direct contact with, the NFT  84 , and chosen such that it does not prevent coupling of electromagnetic energy into and out of the NFT  84 . The heat sink may be composed of a single structure or multiple connected structures, positioned such that they can transfer heat to other metallic features in the head and/or to the gas flow external to the recording head. 
     Although the example of  FIG. 2  shows a perpendicular magnetic recording head and a perpendicular magnetic storage media, it will be appreciated that the disclosure may also be used in conjunction with other types of recording heads and/or storage media as well. It should also be noted that disclosed devices can also be utilized with magnetic recording devices other than HAMR devices. 
       FIG. 3  depicts a view looking down at the air bearing surface (ABS) of a device  300 . The device  300  can include a magnetic reader  305  and a magnetic writer  310 . The magnetic reader  305  and magnetic writer  310  can have details such as those discussed above. In some embodiments, the magnetic writer  310  can also include a NFT, such as those discussed above. The device also includes a variable overcoat. The variable overcoat is positioned over at least the magnetic reader and writer. In some embodiments, the variable overcoat can be positioned over more than just the magnetic reader and writer. The variable overcoat can be a continuous layer, or a non-continuous layer that is positioned over at least a portion of the device on the air bearing surface of the device. In some embodiments, variable overcoats can also include regions that are continuous as well as non-continuous regions, such variable overcoats are described herein as non-continuous. 
     The variable overcoat can be described as including an overcoat layer and at least one disparate overcoat portion. The overcoat layer can generally be described as having a substantially constant thickness, in some embodiments, an overcoat layer having a thickness within ±5 Å can be considered as having a substantially constant thickness. The overcoat layer can also be described as being made of substantially the same material over the entirety of the overcoat layer. Disclosed variable overcoats also generally include at least one disparate overcoat portion. A disparate overcoat portion is a portion of the variable overcoat that can have a substantially different thickness than the overcoat layer, can include a different material than the overcoat layer, or a combination thereof. A substantially different thickness is a thickness that is at least 5 Å thicker or thinner than the average thickness of the overcoat layer. The at least one disparate overcoat portion can be a discrete unconnected portion or it can be a contiguous part of the variable overcoat. Disclosed variable overcoats can include one or more than one disparate overcoat portions. 
     A particular disclosed embodiment of a device can include a variable overcoat that includes a disparate overcoat portion that is positioned over the magnetic writer/NFT. A schematic depiction of such a device is shown in  FIG. 4A . The device  400  in  FIG. 4A  includes a magnetic reader  405 , a magnetic writer  410 , a disparate overcoat portion  415 , and an overcoat layer  420 . The disparate overcoat portion  415  and the overcoat layer  420  make up the variable overcoat layer. The disparate overcoat portion can include a different material than the overcoat layer, can include the same material(s) as the overcoat layer but have a different thickness, or can include at least one different material than the overcoat layer and have a different thickness. 
       FIG. 4B  shows a side view of a device looking crosstrack, with the ABS at the top of the image. The device  400  includes a writer  410 , which is not shown in any detail and can include a writer, and/or a NFT, and a variable overcoat layer that includes an overcoat layer  420  and at least one disparate overcoat region  415 . The overcoat layer  420  can be described by an average height, or thickness, t, as shown in  FIG. 4B . In some embodiments, the overcoat layer can have a thickness, t, from 5 Å to 100 Å, for example.  FIG. 4B  also shows the height h of the disparate overcoat region  415 . The height h of the disparate overcoat region can either be characterized independently or can be characterized with respect to (or as x thicker than) the thickness t of the overcoat layer. Particular heights, h, of the disparate overcoat region can be chosen based on a number of different factors. In some embodiments, disparate overcoat regions such as those depicted in  FIGS. 4A and 4B  can have heights from 5 Å to 60 Å, for example. 
     Such embodiments can be useful in HAMR devices. The HAMR recording process can involve an environment that can be extremely corrosive due to high temperature and exposure to corrosive chemistries. Typically, diamond like carbon (DLC) has been used to protect the write pole material from corrosion. The DLC can also protect features from erosion due to mechanical wear. Instances have been seen in which the DLC has been unable to completely mitigate write pole corrosion. In addition, localized thermal protrusion during the HAMR recording process can subject the writer region to significant burnishing, which in turn can remove a protective head overcoat and accelerate the corrosion process. The aggressive HAMR environment can also lead to DLC failure over the NFT device which can allow migration of the NFT material and eventual device failure. A disparate overcoat portion over the magnetic writer/NFT can function to improve thermal, chemical, and mechanical reliability in the local writer and NFT region. Such a disparate overcoat portion may also be advantageous because it does not increase the thickness of the overcoat over the reader, which increases the head to media spacing (HMS) resulting in a significant performance penalty. 
     In some embodiments having a disparate overcoat portion over the writer/NFT, the disparate overcoat portion can have a greater thickness than the overcoat layer. In some embodiments, the disparate overcoat portion can be about twice as thick than the overcoat layer. In some embodiments, the disparate overcoat portion can have a thickness from 30 Å to 70 Å; and the overcoat layer can have a thickness from 5 Å to 45 Å. In some embodiments, the disparate overcoat portion can have a thickness from 40 Å to 60 Å; and the overcoat layer can have a thickness from 15 Å to 35 Å. In some embodiments, the disparate overcoat portion can have a thickness of 50 Å; and the overcoat layer can a thickness of 25 Å. 
     In some embodiments having a disparate overcoat portion over the writer/NFT, the disparate overcoat portion can include a different material than the overcoat layer. In some embodiments, the disparate overcoat portion and the overcoat layer can include the same material, but one of them also includes a different material. Different materials can be distributed throughout the entire thickness of the disparate overcoat portion (or overcoat layer) or can be in a different layer of the disparate overcoat portion (or overcoat layer). In some embodiments, both the disparate overcoat portion and the overcoat layer can include diamond like carbon (DLC) and one of them can also include an additional material. In some embodiments, both the disparate overcoat portion and the overcoat layer can include diamond like carbon (DLC) and the disparate overcoat portion can also include a second material. In some embodiments, both the disparate overcoat portion and the overcoat layer can include diamond like carbon (DLC) and the disparate overcoat portion can also include oxides, nitrides, carbides, or borides of Tantalum, Titanium, Magnesium, Nickel, Chromium, Beryllium, Zirconium, Silicon, or similar materials. In some embodiments, the disparate overcoat portion can include TaOx. 
     Such embodiments, where a disparate overcoat region is located over the writer, can be fabricated essentially by patterning the writer region (in some embodiments, the writer/NFT region) such that the writer region can be accessed while the reader and the remainder of the ABS are protected. Generally, various combinations of photolithographic and deposition techniques can be utilized. Specific examples of process flow are demonstrated below in discussion of methods disclosed herein. 
     In some embodiments having a disparate overcoat portion over the writer/NFT, the disparate overcoat portion can have a greater thickness than the overcoat layer. In some embodiments, the disparate overcoat portion can be about twice as thick than the overcoat layer. In some embodiments, the disparate overcoat portion can have a thickness from 30 Å to 70 Å; and the overcoat layer can have a thickness from 5 Å to 45 Å. In some embodiments, the disparate overcoat portion can have a thickness from 40 Å to 60 Å; and the overcoat layer can have a thickness from 15 Å to 35 Å. In some embodiments, the disparate overcoat portion can have a thickness of 50 Å; and the overcoat layer can a thickness of 25 Å. 
     In some embodiments having a disparate overcoat portion over the writer/NFT, the disparate overcoat portion can include a different material than the overcoat layer. In some embodiments, the disparate overcoat portion and the overcoat layer can include the same material, but one of them also includes a different material. Different materials can be distributed throughout the entire thickness of the disparate overcoat portion (or overcoat layer) or can be in a different layer of the disparate overcoat portion (or overcoat layer). In some embodiments, both the disparate overcoat portion and the overcoat layer can include diamond like carbon (DLC) and one of them can also include an additional material. In some embodiments, both the disparate overcoat portion and the overcoat layer can include diamond like carbon (DLC) and the disparate overcoat portion can also include a second material. In some embodiments, both the disparate overcoat portion and the overcoat layer can include diamond like carbon (DLC) and the disparate overcoat portion can also include oxides, nitrides, carbides, or borides of Tantalum, Titanium, Magnesium, Nickel, Chromium, Beryllium, Zirconium, Silicon, or similar materials. In some embodiments, the disparate overcoat portion can include TaOx. 
     In some embodiments, the at least one disparate overcoat portion can be located away from both the reader and the writer.  FIG. 5A  shows a schematic of an example of such an embodiment. The device  500  includes a reader  505 , a writer,  510  and a variable overcoat made up of an overcoat layer  525  and two disparate overcoat regions  515  and  520 . As seen in  FIG. 5A , neither of the disparate overcoat regions are located over the writer or the reader. The disparate overcoat regions  510  and  520  in this device can be described as being located on either side, in a downtrack direction, of the magnetic writer. 
       FIG. 5B  shows a side view of a device looking crosstrack, with the ABS at the top of the image. The device  500  includes a transducer  508 , which is not shown in any detail and can include a reader, a writer, and/or a NFT, and a variable overcoat layer that includes an overcoat layer  525  and at least one disparate overcoat region  521 . The overcoat layer  525  can be described by an average height, or thickness, t, as shown in  FIG. 5B . In some embodiments, the overcoat layer can have a thickness, t, from 5 Å to 100 Å, for example. It should be noted that the at least one disparate overcoat region  521  actually hides the second disparate overcoat region, which is located behind the one seen, in the crosstrack direction.  FIG. 5B  also shows the height h of the disparate overcoat region. The height h of the disparate overcoat region can either be characterized independently or can be characterized with respect to (or as x thicker than) the thickness t of the overcoat layer. Particular heights, h, of the disparate overcoat region can be chosen based on a number of different factors. In some embodiments, disparate overcoat regions such as those depicted in  FIGS. 5A and 5B  can have heights from 5 Å to 80 Å, for example. 
     Disparate overcoat regions such as these can function like landing pads or bumper-like surfaces. Landing pads function to contact the disc as the recording head is actuated. The landing pads can contact the disc surface at or before the transducer elements (reader, writer, NFT, etc.) come into contact with the disc surface. Alternatively or additionally, they can function to prevent the reader, writer, or NFT from contacting the disc surface at all. The landing pads can therefore bear the frictional load, increase the total contact area, reduce the wear rate, contribute to the production of the contact detection signal, or some combination thereof. 
     Disparate overcoat regions located away from both the reader and the writer may also have other additional or optional functions. They can have shapes or profiles chosen or designed to control the travel of lubricants and/or contaminant particles in the transducer region. They can be arranged to alter local pressurization, thereby changing the cooling of the surface which could enhance local heater efficiency. They can share the load, upon contact, along with other features on the ABS. They can have wear, due to contact, spread to them in order to minimize wear of more delicate features. 
     Exemplary designs of the disparate overcoat regions can include that depicted in  FIG. 5A , regions placed lateral to the head centerline and/or lateral to transducer features, uptrack or downtrack regions (which can be similarly shaped and designed to formerly utilized contact pads, which were part of the wafer itself), or patterned regions that surround the NFT with a ring or box shape. In some embodiments, the disparate overcoat regions can be located relatively close to regions or features that are to be protected by the disparate overcoat regions. In some embodiments, the disparate overcoat regions can be located as close to the features that are to be protected as processing will allow. In some embodiments, the disparate overcoat regions can be located and designed (shape and dimensions) so that protrusion of the ABS, by the heat of operation, is taken into consideration. In some embodiments, the disparate overcoat regions can be located and designed so the ultimate shape and dimensions are obtained after the head is burnished. 
     In some embodiments, various portions of the variable overcoat layer can include various materials. For example, one or more portions of the variable overcoat layer can include materials that are chosen because of their protective properties (such as wear resistance and corrosion resistance for example), materials that are chosen because of their adhesion promoting properties, materials that are chosen because of their optical properties materials. In some embodiments, materials that may function as dielectric materials that can provided combined optical performance and wear resistance may also be utilized. Exemplary materials that may have protective properties can include diamond like carbon (DLC). Exemplary materials that may have adhesion promoting properties can include tantalum (Ta), titanium (Ti), chromium (Cr), zirconium (Zr), oxides or nitrides thereof, or combinations thereof. 
     Disclosed devices can be fabricated using various techniques. For example, various combinations of photolithographic and deposition techniques can be utilized. A method (or methods) that may be chosen to fabricate a device can depend on the difference between the overcoat layer and the disparate overcoat portion, the location of the disparate overcoat portion(s), the material(s) of the overcoat layer and the disparate overcoat portion, various other considerations not considered herein, or combinations thereof. 
     Exemplary embodiments of disclosed methods can include, for example steps of depositing a first layer on at least a portion of the surface of the substrate; masking at least one region of the surface to form a patterned exposed region; depositing a second layer onto the surface, and removing the mask and second layer, except over the exposed regions.  FIGS. 6A through 6D  depict an exemplary schematic of a device undergoing such a method. It should be noted that  FIGS. 6A to 6D  show a substrate  601 . The substrate  601  can include devices and structures formed therein and thereon, for example the substrate can include a magnetic reader, a magnetic writer, a NFT, or combinations thereof. 
       FIG. 6A  depicts an article  602  that includes a substrate  601  with a first layer  603  deposited thereon. The first layer  603  can be deposited using various methods, including for example sputter deposition, plasma vapor deposition (PVD), chemical vapor deposition (CVD), and evaporative methods. The first layer  603  can include various materials. In some embodiments, the first layer  603  can be a material that can function to protect structures or layers underneath it. As such, the first layer  603  can include, for example diamond like carbon (DLC), TaOx, CSiN. In some embodiments, the first layer  603  can include DLC. 
       FIG. 6B  depicts an article  620  after deposition of a mask layer  605 . The mask layer  605  can be deposited over the entire surface of the first layer  603  or can be deposited over some portion of the first layer  603 . The mask layer  605  can include various materials. In some embodiments, the mask layer  605  can be a material that can be patterned to form voids to ultimately provide various desired structures. As such, the mask layer  605  can include photoresist, and alumina, for example. In some embodiments, the mask layer  605  can include photoresist. 
       FIG. 6C  depicts an article  604 , after the next step: exposing at least one region of the surface of the mask layer  605  to form masked portion(s) and exposed portion(s). The steps depicted in  FIGS. 6B and 6C  are one method of undertaking a step of “masking regions of the surface to form at least one exposed region”. The article  604  includes masked portions  605   a  and  605   b  formed on the surface of the first layer  603 . After exposure, the masked portions  605   a  and  605   b  in the exemplary article, form unexposed regions  615   a  and  615   b  and exposed region  616 . Multiple optional mask regions can form any desired pattern or shape on the surface of the first layer  603 . The masked portions  605   a  and  605   b  can be formed using, for example, photolithography techniques. The masked portions  605   a  and  605   b  can be formed using various photolithographic techniques. 
       FIG. 6D  shows an article  606  after the next step, depositing a second layer onto the surface. The article  606  includes a second layer  607  formed on the surface of the article. In some embodiments, the second layer  607  can be formed over the entire surface of the article. The second layer  607  can be deposited using various methods, including for example sputter deposition, plasma vapor deposition (PVD), chemical vapor deposition (CVD and evaporative methods. The second layer  607  can include various materials. In some embodiments, the second layer  607  can be chosen based on the protective properties of the material. As such, the second layer  607  can include, for example, diamond like carbon (DLC), TaOx, CSiN. In some embodiments, the second layer  607  can include DLC. 
       FIG. 6E  shows an article  608  after the next step, removal of an unexposed portion and a second layer formed thereon, or stated another way, removal of the mask and second layer, except at the exposed regions. This removal step can be accomplished using resist lift off techniques for example. After this step, the article  608  includes a substrate  601  having a first layer  603  thereon, which also has a second layer  611  formed on a portion thereof. The bilayer structure of the portion of the first layer  609  and the portion of the second layer  611  can form a disparate overcoat region. The remainder of the first layer  603  can form the overcoat layer of a variable overcoat. 
       FIGS. 7A to 7D  show articles at various stages of a more specific method such as that depicted in  FIGS. 6A to 6E . The article  702  in  FIG. 7A  begins with a substrate  701  having a transducer  703 , which could include a reader, writer, NFT, or some combination thereof. Deposited on the surface of this is a first layer  705 . The first layer  705  can include a material that can provide protective properties, for example the first layer  705  could include DLC. Next, regions are masked and exposed to create unexposed and exposed regions. An article after completion of this step is depicted in  FIG. 7B . The article  710  includes the components noted in  FIG. 7A  and a patterned mask layer that includes exposed regions  713   a  and  713   b  and unexposed regions  711 . This step can be accomplished using various photolithographic processes which may themselves be multistep processes. Next, a second layer is deposited over the entire surface. An article after completion of this step is depicted in  FIG. 7C . The article  720  includes the components noted in  FIGS. 7A and 7B  as well as a second layer  721  on the unexposed regions  711  and second layer deposits  723   a  and  723   b  which are generally positioned in the exposed regions  713   a  and  713   b . There may also be second layer material that exists on the edges of the second layer  721  on the sides of the exposed region  713   a  and  713   b  voids. The second layer  721  and second layer deposits  723   a  and  723   b  are generally the same material and can be deposited all in one step. In some embodiments, the second layer  721  can be deposited to a thickness of 20 Å to 120 Å. In some embodiments, the second layer  721  can be deposited to a thickness of 40 Å to 100 Å. In some embodiments, the second layer  721  can be deposited to a thickness of 60 Å. The material can include a material that can provide protective properties, for example DLC.  FIG. 7D  shows an article after the next step, removal of the patterned mask layer and portion of the second layer. As seen in  FIG. 7D , the only portion of the second layer that remains are the second layer deposits  723   a  and  723   b.  This step can be accomplished using a single or multiple step process and can include various resist lift off techniques. 
       FIGS. 8A, 8B, and 8C  show optical microscopic images of devices built with variable overcoats that include disparate overcoat regions having thicknesses of 40 Å ( FIG. 8A ), 60 Å ( FIG. 8B ), and 80 Å ( FIG. 8C ). The disparate overcoat regions are shown by the arrows in each of the images. These disparate overcoat regions were made using a method such as that depicted in  FIGS. 7A to 7D . 
     The above disclosed method can be utilized to make various types of variable overcoats. In some embodiments, the above disclosed methods can be utilized to make variable overcoats having at least one disparate overcoat region positioned away from both the magnetic reader and magnetic writer. However, it should be noted that the specific methods as well as concepts therein can be utilized in making variable overcoats having at least one disparate overcoat region located over the magnetic writer. 
     In some embodiments, variable overcoats having at least one disparate overcoat region located over the magnetic writer can be made using various methods. Methods of producing such devices can be simplistically classified as either producing different voids over the different areas or filling them or as forming layers and etching differently. Both concepts can be accomplished in various ways by using a combination of photolithographic techniques. 
     One exemplary method includes forming or obtaining a structure, the structure having a magnetic reader and a magnetic writer, wherein the magnetic reader and the magnetic writer are positioned adjacent to each other on a substrate. Such an article is depicted in  FIG. 9A . The article  902  includes a substrate  904  having a magnetic reader  906  and a magnetic writer  908  positioned thereon or therein. The article  910  after the next step, depositing a first layer over the entire surface of the structure is depicted in  FIG. 9B . The article  910  includes the components noted above in  FIG. 9A  and a first layer  912 . The first layer  912  can include a material that can provide protective properties, for example DLC. Alternatively, the first layer  912  can include a material that is designed to increase the adhesion of later deposited layers. In some such embodiments, the first layer can include TaOx. In some such embodiments, the first layer can have a thickness of 35 Å and 25 Å of it can later be removed (in the next step). In other embodiments, the first layer can have a thickness of 60 Å and 50 Å of it can later be removed (in the next step). The article  920  after the next step, removing a portion of the first layer over the magnetic reader is shown in  FIG. 9C . The article  920  includes the components noted above as well as a modified portion of the first layer  922 . The modified portion of the first layer  922  is positioned at least over the magnetic reader  906 . This step can be accomplished using various mask and etch steps including for example photolithographic techniques. The article  930  after the next step, depositing a second layer over the entire surface of the first layer is depicted in  FIG. 9D . The article  930  includes the components noted above as well as a second layer  932 . The second layer  932  can include a material that can provide protective properties, for example DLC. The second layer  932  forms a disparate overcoat region  936  positioned over the magnetic writer  908 . The remainder of the second layer  932  forms an overcoat layer  934  that is thinner than the variable overcoat region  936 . 
     Another exemplary method includes forming or providing a structure, the structure having at least a magnetic writer on or in a substrate. Such an article is depicted in  FIG. 10A . The article  1000  can include a substrate  1002  with a magnetic writer  1004  positioned therein or thereon. The next step can include depositing a first layer on the entire surface of the structure. The article depicted in  FIG. 10A  includes a first layer  1006  positioned on the entire surface of the substrate  1002  and writer  1004 . The first layer  1006  can include a material that can provide protective properties, for example DLC. The next step can include removing a portion of the first layer over everything but the magnetic writer. The article  1010  depicted in  FIG. 10B  depicts one method of undertaking that step, by masking the portion of the first layer  1006  over the writer  1004  with a mask  1012 . This can be accomplished using various photolithographic techniques. The mask  1012  can include materials such as photoresist, or alumina, for example.  FIG. 10C  depicts the article  1020  after the remainder of the first layer is removed leaving a portion of the first layer  1022  between the mask  1012  and the magnetic writer  1004 . This step can be accomplished using various etching techniques. The next step can include depositing a second layer over the structure. An article after completion of this step is seen in  FIG. 10D . The article  1030  can include the components seen above in  FIG. 10C  as well as a second layer  1032 . The second layer  1032  can include a material that can provide protective properties, for example DLC. The second layer functions to form a variable overcoat layer that includes a disparate overcoat region  1034  and an overcoat layer (the remainder of the second layer  1032 ). The disparate overcoat region  1034  in this example can include the portion of the first layer  1022 , the mask  1012  and the portion of the second layer  1032 . It should also be noted that the mask  1012  could be removed before the second layer  1032  is deposited to create a disparate overcoat region that would include the portion of the first layer  1022  and the portion of the second layer  1032 . 
     One specific exemplary method is as follows. The first step is to define the reader/writer/NFT dimensions and finish the ABS surface. This can be accomplished by kisslapping for example. Next, an overcoat, such as diamond like carbon (DLC) is deposited on the reader/writer/NFT. The DLC layer can be about 2 nm thick for example. Then, a hard mask is deposited on the DLC layer. An exemplary hard mask material includes alumina (Al 2 O 3 ). Next, photo patterning techniques are utilized to protect the reader from the further processing meaning that the DLC layer already applied will ultimately be the hard mask layer over the reader. The effect of these steps is that a protective structure is built over the reader region leaving the writer/NFT region open for formation of additional layers.  FIG. 11A  shows an article at the point where the protective structure has been built over the reader but the DLC has not yet been etched off of the writer/NFT region.  FIG. 11B  shows the article immediately after the DLC layer has been removed from the writer/NFT region. Next, an alternative overcoat layer (the same material at a different thickness, a different material at the same thickness, or a different material at a different thickness) is deposited over the writer/NFT region. Once the alternative overcoat layer has been deposited, the protective structure over the reader region can then be removed.  FIG. 11C  shows the article after this step. 
     Another specific exemplary method is as follows. The device is blanketed with a layer of TaOx, for example. This TaOx layer can have a thickness from about 25 Å to about 75 Å. In some embodiments it can have a thickness from about 35 Å to about 60 Å. A device (completed) is shown in  FIG. 12 . The device in  FIG. 12  includes the TaO blanket over both the reader (R) and the writer (W). Optionally, a DLC cap layer can be deposited over the TaO blanket (this is not shown in  FIG. 12 ). The DLC cap layer, if present can have a thickness from about 5 Å to about 15 Å. In some embodiments, it can have a thickness of about 10 Å. Next, a protective structure is built over the writer/NFT region. This can be done using photo patterning techniques for example. In some embodiments, the protective structure can be a single layer resist that is a 60 μm×5 μm feature. Next, a portion of the TaO layer is etched away everywhere but where the protective structure is located. Then, the protective structure is removed. This results in a layer of TaOx over the writer that is thicker than the layer of TaOx over the reader. This can be seen in  FIG. 12 , where the TaO step is the thicker portion over the writer. After this, a blanket coating of DLC is applied over the entire structure. A finished article from this method is depicted in  FIG. 12 . 
     Thus, embodiments of magnetic devices including variable overcoat layers are disclosed. The implementations described above and other implementations are within the scope of the following claims. One skilled in the art will appreciate that the present disclosure can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation.