Abstract:
A method for fabricating a magnetic head wherein a read head portion of the magnetic head includes a second gap insulation layer that includes a first portion that is fabricated upon the electrical leads of the read head and a second portion that is fabricated upon both a sensor portion of the read head and the first portion of the insulation layer. Both the first portion and the second portion of the insulation layer are made up of multi-layered laminations. Each said lamination is fabricated by depositing a thin film of metal, followed by the oxidation of that metallic thin film.

Description:
CROSS REFERENCE TO RELATED APPLICAYIONS 
     This application is a divisional application, and claims the benefit of U.S. patent application Ser. No. 09/772,780 filed Jan. 29, 2001, now U.S. Pat. No. 6,707,647 issued Mar. 16, 2004. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the fabrication of magnetic heads for hard disk drives, and particularly to the fabrication of insulation layers within the read head portions of such magnetic heads. 
     2. Description of the Prior Art 
     To increase the areal data storage density of hard disks for hard disk drives, the data bits within the tracks upon such hard disks are written closer together, so that a greater number of bits per inch are recorded. To efficiently read data from a data track with such a greater number of bits, the read head portion of a magnetic head of a hard disk drive must be structured such that the resolution of the read heads is increased. 
     The read heads of the prior art magnetic heads are fabricated utilizing thin film deposition techniques on an upper surface of a wafer substrate. In fabricating the read head portion, a first electrical insulation layer is deposited upon the surface of the substrate, followed by the deposition of a magnetic shield, followed by a first gap insulation layer, followed by the fabrication of a plurality of layers and structures that generally include a plurality of active read head magnetic layers, magnetic hard bias elements and electrical lead traces. Thereafter, a second gap insulation layer is deposited, followed by a second magnetic shield, another insulation layer, and further magnetic head components such as write head structures, that complete the magnetic head. 
     One of the problems associated with prior art read heads so designed is that they have thick gap insulation layers. Consequently, the prior art read heads display low resolution because resolution is adversely affected by the spacing between the two magnetic shields i.e. thicker the gap insulation layers, greater the spacing between the two magnetic shields and lower the resolution. Even read heads designed with thinner gap insulation layers are not free of problems. One of the problems associated with prior art read heads with thinner gap insulation layers is the increased potential for electrical shorts between the electrical leads (and the sensor) and the magnetic shields due to the thinness of the gap insulation layers. Another problem associated with prior art read heads with thinner gap insulation layers is the lack of efficient electrical insulation. In these read heads, the gap insulation layers are so thin that they are unable to perform the function of electrical insulation effectively. 
     The present invention seeks to solve these problems associated with prior art read heads by providing new gap materials and deposition methods to produce thinner gap insulation layers that ensure high resolution of the read heads and that also provide robust electrical insulation. 
     SUMMARY OF THE INVENTION 
     The hard disk drive of the present invention includes a magnetic head wherein the read head portions of the magnetic head have novel gap insulation layers between the sensor and the two magnetic shields. In a preferred embodiment, the second of the gap insulation layers is made up of two portions. The first gap insulation portion is disposed over electrical leads in the read head and is thick enough to help ensure electrical insulation between the electrical leads and the second magnetic shield. The second portion of the gap insulation layer is disposed over the first gap insulation portion and also directly over the top portion of the sensor. It can be thinner than the first gap insulation portion. The second gap insulation portion ensures minimal spacing between the two magnetic shields. The gap insulation layers are made up of multilayer laminations wherein each lamination in the multilayered structure is made of an oxide of a metal selected from the group consisting of aluminum, silicon, chromium and tantalum. In accordance with the present invention, the fabrication of an individual lamination layer is a two step process starting-with the deposition of a thin film of metal on a substrate layer, and then the oxidation of the deposited metal film to form a first metal oxide lamination. Each lamination may have a thickness of 10 Å to 50 Å. The process is repeated until a multilayered lamination structure of a desired thickness is formed. A preferred embodiment of the present invention includes 5–10 laminations in the multilayer structure, such that the total thickness of a gap insulation layer is approximately 50 Å–500 Å. The laminations are each fabricated by a process such as sputter deposition. 
     It is an advantage of the magnetic head of the present invention that it includes thin G 1  and G 2  gap insulation layers such that the distance between the magnetic shields of the read head is reduced. 
     It is another advantage of the magnetic head of the present invention that it includes a G 2  insulation layer having a first gap insulation layer portion and a second gap insulation portion, wherein the first gap insulation portion is disposed over the read head electrical leads and the second portion is disposed over the sensor and the first gap insulation layer portion. 
     It is a further advantage of the magnetic head of the present invention that it includes a read head with a G 2  insulation layer having a thinner second gap insulation portion formed of a laminated multilayer structure that reduces the distance between the sensor and the second magnetic shield. 
     These and other features and advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following detailed description, which makes reference to the several figures of the drawings. 
    
    
     
       IN THE DRAWINGS 
         FIG. 1  is a top plan view of a typical hard disk drive including a magnetic head of the present invention; 
         FIG. 2  is a side cross-sectional view of a prior art read head portion of a magnetic head; 
         FIG. 3  is a side cross-sectional view of a fabrication step of the read head of the magnetic head of the present invention; 
         FIG. 4  is a side cross-sectional view of a further fabrication step of the read head of the magnetic head of the present invention; 
         FIG. 5   a  is a side cross-sectional view of a first fabrication step of a gap insulation layer of the present invention; 
         FIG. 5   b  is a side cross-sectional view of a second fabrication step of the gap insulation layer of the present invention; 
         FIG. 5   c  is a side cross-sectional view of a third fabrication step of the gap insulation layer of the present invention; 
         FIG. 5   d  is a side cross-sectional view of a fourth fabrication step of the gap insulation layer of the present invention; 
         FIG. 5   e  is a side cross-sectional view of a fifth fabrication step of the gap insulation layer of the present invention; 
         FIG. 6  is a side cross-sectional view of another fabrication step of the read head of the present invention showing multilayer laminations forming the first portion of the G 2  gap insulation layer over the electrical leads as shown after photoresist mask lift-off; 
         FIG. 7  is a side cross-sectional view of a further fabrication step of the read head of the present invention showing multilayer laminations of the second portion of the G 2  gap insulation layer over the sensor and the first portion of the G 2  gap insulation layer; 
         FIG. 8  is a side cross-sectional view of yet another fabrication step of the read head with the contoured second magnetic shield on top of the G 2  gap layer of the present invention; and 
         FIG. 9  is a side cross-sectional view of a read head of the present invention with both the G 1  and G 2  gap insulation layers being formed of multilayer laminations. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a top plan view that depicts significant components of a hard disk drive, which includes the magnetic head of the present invention. The hard disk drive  10  includes a magnetic media hard disk  12  that is rotatably mounted upon a motorized spindle  14 . An actuator arm  16  is pivotally mounted within the hard disk drive  10  with a magnetic head  20  of the present invention disposed upon a distal end  22  of the actuator arms  16 . A typical hard disk drive  10  may include a plurality of disks  12  that are rotatably mounted upon the spindle  14  and a plurality of actuator arms  16  having a magnetic head  20  mounted upon the distal end  22  of the actuator arms. As is well known to those skilled in the art, when the hard disk drive  10  is operated, the hard disk  12  rotates upon the spindle  14  and the magnetic head  20  acts as an air bearing slider that is adapted for flying above the surface of the rotating disk. The slider includes a substrate base upon which the various layers and structures that form the magnetic heads are fabricated. Such heads are fabricated in large quantities upon a wafer substrate and subsequently sliced into discrete magnetic heads  20 . 
       FIG. 2  is a cross-sectional view of a prior art read head portion  40  of a magnetic head shown to facilitate the understanding of the present invention. As is well known to those skilled in the art, the prior art read head structure  40 , is fabricated utilizing thin film deposition techniques on an upper surface  44  of a wafer substrate  48 . In fabricating the read head portion  40  of the prior art magnetic head, a first electrical insulation layer  52  is deposited upon the surface  44  of the substrate  48 , followed by the deposition of a first magnetic shield  56 , followed by a first gap insulation layer  60 , followed by the fabrication of a plurality of layers and structures that generally include a plurality of active read head magnetic layers  66 , magnetic hard bias elements  70  and electrical lead traces  74 . Thereafter, a second gap insulation layer  80  is deposited, followed by a second magnetic shield  84 , another insulation layer  86 , and further magnetic head components (not shown), such as write head structures, that complete the magnetic head. In some prior art magnetic head designs, the second magnetic shield  84  may also function as one of the magnetic poles of the write head structure. 
     A problem that exists with the prior art magnetic heads is that the read head portions in these magnetic heads have thick gap insulation layers. Consequently, the prior art read heads lack good resolution powers. Second, the prior art read heads designed with thinner gap insulation layers suffer from the potential risk of electrical shorts occurring between the sensor or the electrical leads and the magnetic shields because the electrical insulation integrity of the gap insulation layers in these read heads is not sufficient. The present invention seeks to eliminate these problems through the fabrication of laminated gap insulation layers that help provide high resolution read heads with robust electrical insulation. 
       FIG. 3  is a side cross-sectional view of a fabrication step for the gap insulation layers of the read head portion  100  of the magnetic head  20  of the hard disk drive  10  of the present invention as shown in  FIG. 1 . As depicted in  FIG. 3 , the read head portion  100  of the present invention includes several features that may be substantially identical to features of the prior art read head  40 , and such substantially identical features are identically numbered. The read head portion  100  of the present invention thus includes a first insulation layer  52  that is fabricated upon the surface  44  of a wafer substrate  48 . A first magnetic shield structure  56  is fabricated upon the first insulation layer  52  and a first gap insulation layer  60  (G 1  layer) is fabricated upon the first magnetic shield  56 . As is conducted in the prior art head fabrication process, a patterned photoresist mask  102  is fabricated with a portion  104  to cover the active read head sensor layers  66  and with openings  106  for hard bias elements  70  and electrical leads  74 . Thereafter the hard bias elements  70  and electrical leads  74  are deposited onto the wafer and into the openings  106 , and hard bias material  90  and electrical lead material  92  is also deposited on top of the photoresist mask  102 . The second gap insulation layer (G 2  layer)  108  of the present invention is next fabricated. A preferred embodiment of the G 2  gap insulation layer  108  comprised of two insulation portions, and the fabrication of the first portion  112  of the G 2  gap insulation layer  108  of the present invention is next described with the aid of  FIG. 4 , which is an expanded view of the central portion of  FIG. 3 . 
     As depicted in  FIG. 4 , the first portion  112  of the G 2  insulation layer  108  is deposited over the surface of the wafer into the openings  106  and onto the electrical leads  74 . It is to be noted that the portion  104  of the photoresist mask that is deposited on top of the sensor layers  66  prevents the insulation layer  112  from being deposited upon the sensor  66 . The layer  112  is comprised of a plurality of layers  116  that form a multilayered laminated structure. A detailed description of the fabrication of a multilayer laminated structure which is utilized as layer  112  is next presented with the aid of  FIGS. 5   a – 5   d.    
       FIG. 5   a  is a side cross-sectional view of the first fabrication step to form an insulation layer  120  which serves as the G 1  and G 2  gap layers of the present invention. As depicted in  FIG. 5   a , a film of metal  130  is deposited on top of a substrate  134  preferably using a sputter deposition process that is conducted in a vacuum deposition chamber. The thickness of the metal film  130  is in the range of approximately 10–50 Å, and in the preferred embodiment, the thickness of the metal film is in the range of approximately 10–20 Å. In accordance with a preferred embodiment of the present invention, the metal film may be comprised of aluminum, silicon, chromium or tantalum. 
       FIG. 5   b  is a side cross-sectional view of the second fabrication step of the insulation layer  120 . As shown in  FIG. 5   b , the thin metal film  130  deposited over the substrate is then oxidized by the introduction of oxygen into the vacuum deposition chamber. This results in the formation of a lamination of metal oxide  140  on the substrate, which corresponds to a first lamination layer  116  of the G 2  gap layer portion  112 . It is important that the thin metal film  130  be oxidized completely because incomplete oxidation may cause remnants of the metal to be left behind in the gap insulation layer causing them to interfere with the layer&#39;s function of electrical insulation. It is also important that the metal thin film  130  not exceed approximately 50 Å in thickness because a thick metal film will not oxidize completely. 
       FIG. 5   c  is a side cross-sectional view of the third fabrication step of the insulation layer  120  of the present invention. As shown in  FIG. 5   c , a second thin film metal layer  144  is deposited over the first lamination layer  140 . 
       FIG. 5   d  is a side cross-sectional view of the fourth fabrication step of the insulation layer  120  of the present invention. In the fourth step, the second thin film layer  144  deposited over the first lamination  140  is oxidized in the same manner as the first metal layer  130 . This results in the formation of a second lamination layer of metal oxide  150  on top of the substrate  134  which corresponds to a second lamination  116  of the G 2  gap layer portion  112 . 
       FIG. 5   e  is a side cross-sectional view showing further fabrication steps of the insulation layer  120  of the read head portion of a magnetic head of the present invention including a further metal oxide layer  160  which corresponds to a further lamination  116  of the G 2  gap layer portion  112 . As shown in  FIG. 5   e , a multilayered laminated structure  120  is formed by the repeated metal thin film layer deposition and oxidation steps described above with regard to metal oxide layers  140 ,  150  and  160  above, until a desired thickness of the insulation layer  120  is achieved. With reference to  FIG. 4 , an embodiment of the first portion  112  of the G 2  gap insulation layer  108  is formed with 5–10 laminations  116 , each having a thickness of approximately 10 Å to 50 Å; such that the first portion  112  has a total thickness in the range of from approximately 50 Å to approximately 500 Å, and in a preferred embodiment of the present invention has a thickness of approximately 250 Å. 
       FIG. 6  is a side cross-sectional view of the read head of the present invention showing a further fabrication step of a second insulation portion  180  of the G 2  insulation layer  108  of the present invention. As depicted in  FIG. 6 , the photoresist mask  102  (and center portion  104 ) is removed by the use of a suitable solvent as is known to those of ordinary skill in the art, leaving the laminations  112  deposited in the photoresist openings intact and covering the electrical leads  74 . 
       FIG. 7  is a side cross-sectional view of a read head of the magnetic head of the present invention showing the fabrication of further multilayer laminations  184  of metal oxide forming the second insulation layer portion  180  of the G 2  gap insulation layer  108 . The second insulation layer portion  180  covers both the active areas of the sensor  66  and the first portion  112  of the G 2  insulation layer  108  on top of the electrical leads  74 . The metal oxide laminations  184  are deposited utilizing the insulation layer fabrication process described hereinabove with reference to  FIGS. 5   a–e.    
     Following the fabrication of the second insulation portion  180  of the G 2  insulation layer  108 , the second magnetic shield  190  is fabricated, and  FIG. 8  is a side cross-sectional view of the read head portion  100  of the magnetic head  20  of the present invention showing the contoured magnetic shield  190  deposited over the G 2  gap insulation layer  108  of the present invention, such that a central portion  194  of the shield  190  is formed over the sensor  66 . Further components of the magnetic head  20  of the present invention, such as write head structures are thereafter fabricated as known to those skilled in the art. 
       FIG. 9  is a side cross-sectional view of a further embodiment of the present invention in which the G 1  gap insulation layer  60  is also formed of multilayer laminations  198 . The G 1  gap insulation layer laminations  198  are fabricated in the same manner as the first G 2  gap insulation layer  112  as described hereinabove with reference to  FIGS. 5   a–e . In accordance with an alternative embodiment of the present invention, a multilayer structure of metal nitride laminations (rather than metal oxide laminations) may be fabricated to form the G 1  and/or G 2  gap insulation layers. Metal nitride layers alternating with metal oxide layers are also within the scope of the invention. 
     It will therefore be understood that the read head portion  100  of the magnetic head  20  has G 1  and G 2  gap insulation layers disposed between the magnetic shields  56  and  190  and the sensor  66 . In a preferred embodiment, the first insulation layer portion  112  of the G 2  insulation layer  108  is a thicker portion deposited directly over the electrical leads, and its purpose is to help to electrically insulate the electrical leads from the second magnetic shield  190 . The second insulation portion  180  of the G 2  gap insulation layer  108  may be a thinner portion disposed over the sensor  66  (and the first portion  112 ), and it allows for a minimal insulation gap distance between the sensor  66  and the central portion  194  of the magnetic shield  190  located proximate the sensor  66 , while at the same time minimizing electrical shorts between the sensor  66  and the shield  190 . Where the G 1  gap insulation layer is approximately 250 Å thick and the second portion  180  of the G 2  layer  108  is approximately 250 Å, and the thickness of the sensor  66  is approximately 500 Å, the shield to shield distance of the magnetic head  20  is approximately 1000 Å. The magnetic head  20  therefore has increased resolution of magnetic data bits, and this results in a hard drive  10  of the present invention wherein the magnetic head  20  is able to read magnetic disks with increased areal data storage density. 
     While the invention has been shown and described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various alterations in form and detail may be made therein without departing from the true spirit and scope of the invention. It is therefore intended that the following claims cover all such alterations and modifications in form and detail that nevertheless include the true spirit and scope of the invention.