Abstract:
A magnetic read/write head having improved thermal characteristics. The read/write head includes a read element and a write element formed there over. The read element includes a read sensor embedded within a dielectric material and sandwiched between first and second shields. The write element includes first and second poles joined to form a yoke. The yoke is closed at one end and defines a write gap at the other. A coil having windings which extend through the yoke generates a magnetic flux within the yoke. This magnetic flux causes a magnetic fringe field at the location of the write gap, the fringe field being capable of imparting a magnetic signal onto a passing magnetic medium. The coil sits atop a thermally conductive, electrically insulating material which electrically isolates the coil from surrounding structure. When a current flows through the coil, heat will be generated. Such heat, which could be detrimental to read performance, is conducted through the thermally conductive material out of the yoke and away from the write element. The thermally conductive material provides a large heat sink for dissipation of the heat.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to magnetic disk data storage systems, and more particularly to magnetic write transducers and methods for making same. 
     Magnetic disk drives are used to store and retrieve data for digital electronic apparatuses such as computers. In FIG. 1A and 1B, a magnetic disk data storage systems  10  of the background art includes a sealed enclosure  12 , a disk drive motor  14 , a magnetic disk  16 , supported for rotation by a drive spindle S 1  of motor  14 , an actuator  18  and an arm  20  attached to an actuator spindle S 2  of actuator  18 . A suspension  22  is coupled at one end to the arm  20 , and at its other end to a read/write head or transducer  24 . The transducer  24  (which will be described in greater detail with reference to FIG. 2A) typically includes an inductive write element with a sensor read element. As the motor  14  rotates the magnetic disk  16 , as indicated by the arrow R, an air bearing is formed under the transducer  24  causing it to lift slightly off of the surface of the magnetic disk  16 , or, as it is termed in the art, to “fly” above the magnetic disk  16 . Alternatively, some transducers, known as “contact heads,” ride on the disk surface. Various magnetic “tracks” of information can be written to and/or read from the magnetic disk  16  as the actuator  18  causes the transducer  24  to pivot in a short arc as indicated by the arrows P. The design and manufacture of magnetic disk data storage systems is well known to those skilled in the art. 
     FIG. 2A depicts a magnetic read/write head  24  including a substrate  25  above which a read element  26  and a write element  28  are disposed. Edges of the read element  26  and write element  28  also define an air bearing surface ABS, in a plane  29 , which can be aligned to face the surface of the magnetic disk  16  (see FIG.  1 A and  1 B). The read element  26  includes a first shield  30 , an intermediate layer  32 , which functions as a second shield, and a read sensor  34  that is located within a dielectric medium  35  between the first shield  30  and the second shield  32 . The most common type of read sensor  34  used in the read/write head  24  is the magnetoresistive (AMR or GMR) sensor which is used to detect magnetic field signals from a magnetic medium through changing resistance in the read sensor. 
     The write element  28  is typically an inductive write element which includes the intermediate layer  32 , which functions as a first pole, and a second pole  38  disposed above the first pole  32 . The first pole  32  and the second pole  38  are attached to each other by a backgap portion  40 , with these three elements collectively forming a yoke  41 . The combination of a first pole tip portion  43  and a second pole tip portion  45  near the ABS are sometimes referred to as the yoke tip portion  46 . A write gap  36  is formed between the first and second poles  32 ,  38  in the yoke tip portion  46 . The write gap  36  is filled with a non-magnetic electrically insulating material that forms a write gap material layer  37 . This non-magnetic material can be either integral with (as is shown here) or separate from a first insulation layer  47  that lies below the second yoke  38  and extends from the yoke tip portion  46  to the backgap portion  40 . 
     Also included in write element  28  is a conductive coil  48 , formed of multiple winds  49  which each have a wind height Hw. The coil  48  can be characterized by a dimension sometimes referred to as the wind pitch P, which is the distance from one coil wind front edge to the next coil wind front edge, as shown in FIG.  2 A. As is shown, the wind pitch P is defined by the sum of the wind thickness Tw and the separation between adjacent winds Sw. The conductive coil  48  is positioned within a coil insulation layer  50  that lies above the first insulation layer  47 . The first insulation layer  47  thereby electrically insulates the coil layer from the first pole  32 , while the coil insulation layer  50  electrically insulates the winds  49  from each other and from the second pole  38 . 
     The configuration of the conductive coil  48  can be better understood with reference to a plan view of the read/write head  24  shown in FIG. 2B taken along line  2 B— 2 B of FIG.  2 A. Because the conductive coil extends beyond the first and second poles, insulation may be needed beneath, as well as above, the conductive coil to electrically insulate the conductive coil from other structures. For example, as shown in FIG. 2C, a view taken along line  2 C— 2 C of FIG. 2A, a buildup insulation layer  52  can be formed adjacent the first pole, and under the conductive coil layer  48 . As is well known to those skilled in the art, these elements operate to magnetically write data on a magnetic medium such as a magnetic disk  16  (see FIGS.  1 A and  1 B). 
     More specifically, an inductive write head such as that shown in FIGS. 2A-2C operates by passing a writing current through the conductive coil layer  48 . Because of the magnetic properties of the yoke  41 , a magnetic flux is induced in the first and second poles  32 ,  38  by write currents passed through the coil layer  48 . The write gap  36  allows the magnetic flux to fringe out from the yoke  41  (thus forming a fringing gap field) and to cross a magnetic recording medium that is placed near the ABS. A critical parameter of a magnetic write element is a trackwidth of the write element, which defines track density. For example, a narrower trackwidth can result in a higher magnetic recording density. The trackwidth is defined by geometries in the yoke tip portion  46  (see FIG. 2A) at the ABS. These geometries can be better understood with reference to FIG.  2 C. As can be seen from this view, the first and second poles  32 ,  38  can have different widths W 1 , W 2  respectively in the yoke tip portion  46  (see FIG.  2 A). In the shown configuration, the trackwidth of the write element  28  is defined by the width W 2  of the second pole  38 . The gap field of the write element can be affected by the throat height TH, which is measured from the ABS to the zero throat ZT, as shown in FIG.  2 A. Thus, accurate definition of the trackwidth and throat height is critical during the fabrication of the write element. 
     Another parameter of the write element is the number of winds  49  in the coil layer  48 , which determines magnetic motive force (MMF) of a write element. With increasing number of winds  49  between the first and second poles  32 ,  38 , the fringing field is stronger and, thus, the write performance increases. The number of winds is limited by the yoke length YL, shown in FIG. 2A, and the pitch P between adjacent winds  49 . However, to obtain faster recording speeds, and therefore higher data transfer rates, it may be desirable to have a shorter yoke length YL because this can shorten the flux rise time. This relationship can be seen in the graph of yoke length YL versus flux rise time shown in FIG.  2 D. Therefore, to maximize the number of coil winds while maintaining fast write speeds, it is desirable to minimize the pitch P in design of write elements. 
     However, the control of trackwidth, throat height, and coil pitch can be limited by typical fabrication processes, an example of which is shown in the process diagram of FIG.  3 . The method  54  includes providing a first pole with first and second edges in operation  56 . This operation can include, for example, forming a plating dam, plating, and then removing the dam. In operation  58 , a write gap material layer is formed over the first pole. In particular, the write gap material layer is formed over an upper surface and the first and second edges of the first pole. Also, in operation  58 , a via is formed through the write gap material layer to the first pole in the backgap portion  40  (see FIG.  2 A). In the instance herein described, the write gap material layer extends above the first pole in the area between the yoke tip portion and the backgap portion, although in other cases the write gap material layer may not be above this area. A buildup insulation layer is also formed in operation  60 , adjacent the first and second edges, with the write gap material layer between the first pole and the buildup insulation layer. The buildup insulation layer is typically formed by depositing (e.g., spinning) and patterning photoresistive material and then hard baking the remaining photoresistive material. Such processes often result in the height of the buildup insulation layer being non-uniform and different than the height of the write gap material layer, as is illustrated in FIGS. 2A and 2C. 
     The method  54  also includes forming a first coil layer above the write gap material layer and the buildup insulation layer in operation  62 . This can include first depositing a seed layer above the first pole. Typically, photoresistive material can then be deposited and patterned. With the patterned photoresistive material in place, conductive material can be plated. With removal of the photoresistive material, the remaining conductive material thereby forms the coil. 
     Unfortunately, when there is a difference in height between the write gap material layer and the buildup insulation layer, the patterning of the photoresistive material for the first coil layer can be complicated. In particular, it can be difficult to pattern the various heights to have consistent geometries. More specifically, winds of the resulting first coil layer can be wider at lower levels than at higher levels, such as between the first and second poles. Thus, for a given pitch, such greater width at the lower levels can result in smaller distances between winds. This can, in turn, result in electrical shorting between winds which can be detrimental to the write element performance. To avoid such electrical shorting, the minimum wind pitch can be set to a desired value that will result in adequate yield of non-shorting conductive coil layers. Because the coil winds are more narrow between the first and second poles, the resulting pitch there is typically greater than, and limited by this minimum. For example, typical wind pitches between the first and second poles may be limited to no less than about 3 microns. For a given number of winds and wind thickness, this in turn limits the minimum yoke length, and thereby limits the data transfer rate and data density as described above. For example, a pitch of about 3 microns may be adequate for recording densities on the order of about 2 Gb/sq.in., however, these typical pitches can be inadequate for larger recording densities, such as about 10 Gb/sq.in. 
     In operation  64 , the method  54  further includes forming a coil insulation layer above the first coil layer that is formed in operation  62 . In addition, in operation  66  a second pole is formed above the coil insulation layer of operation  64 . 
     Still another parameter of the write element is the stack height SH, the distance between the top surface of the first pole  32  and the top of the second pole  38 , as shown in FIG.  2 A. Of course, this height is affected by the thickness of the first insulation layer  47 , the thickness of the coil layer  48  and any other coil layers that might be included, and the height Hi of the coil insulation layer  50  and any other coil insulation layers that might be included. The stack height SH can be an indicator of the apex angle α, which partially characterizes the topology over which the second pole must be formed near the yoke tip portion. Typically, the reliability of the write element decreases as the apex angle a increases. This is due, at least in part, to the corresponding increased difficulty, particularly in the yoke tip portion  46 , of forming the second pole  38  over the higher topography of the stack. For example, the definition of the second pole width W, shown in FIG. 2C, including photoresist deposition and etching, can be decreasingly reliable and precise with increasing topography. When demand for higher density writing capabilities drives yoke tip portions to have smaller widths W, this aspect of fabrication becomes increasingly problematic. 
     In attempts to accommodate ever increasing data rate requirements, the above described design parameters are continually adjusted to the limits of available manufacturing capabilities. For example, yoke length YL must be shortened in order to minimize flux rise time. This means that the pitch P of the coil  48  must be minimized, requiring a reduction in wind thickness Tw accordingly. The reduction in wind thickness leads to a corresponding increase in electrical resistance in the winds  49 . 
     Also, in order to minimize the yoke length YL, the number of winds  49  in a coil  48  must be reduced. However, with less winds available the current generated through the coil must be increased in order to maintain a sufficient magnetic motive force. This increase in current through the coil  48  along with the increased resistance of the winds  49 , causes a dramatic increase in heat generation. The heat generated by the coil  48  during operation is defined by the formula W=I 2 R, where W is the amount of heat generated per second, I is the current flowing through the coil, and R is the electrical resistance of the coil. 
     The increased heat generated by a coil  48  of a high performance write element  28  degrades the performance of the read element  26 . One reason for this decrease in performance is that the heat will cause thermal stresses on the read/write head  24  as the various materials expand at different rates. These thermal stresses will in turn cause magnetic domain motion in shield  32  which generates magnetic flux into read sensor  34 . Due to magneto-resistive properties of the sensor, this undesired magnetic flux will be interpreted as a magnetic field. Another reason for this degradation of performance is that heat conducted to the read sensor  34  will cause “Johnson Thermal Noise”. “Johnson Thermal Noise” is proportional to (ω)(K B T)(R) where ω is the frequency of the signal being read, K B T is the temperature of the sensor in degrees Kelvin and R is the resistance of the sensor. 
     Therefore, there remains a need for a high performance read/write head which can accommodate high data rate transfer while effectively dealing with increased heat generation. Such a read/write head would preferably experience negligible thermal interference in its read element, and would preferably not require an appreciable increase in manufacturing cost. 
     SUMMARY OF THE INVENTION 
     The present invention provides a magnetic write head, and a method for manufacturing same, having a structure for dissipating heat. The write head includes first and second magnetic poles joined at one end to form a yoke. A coil having a portion of its winds extending through the yoke imparts a magnetic flux through the yoke when an electrical current is caused to flow through the coil. The coil sits upon a layer of dielectric, thermally conductive material, which conducts and dissipates heat generated by the coil. 
     The preferred embodiment of the present invention includes a read element and a write element combined to form a combination read/write head, all of which is built upon a ceramic substrate. The read portion of the head includes a read sensor embedded within a first dielectric layer. This first dielectric layer is sandwiched between a first and a second shield. 
     The second shield of the read element serves as a portion of the first pole of the write element. The second shield/first pole has a flat upper surface, from which extends a write gap pedestal and a back gap pedestal. A second dielectric layer is formed over the first pole, and is planarized by a chemical mechanical polishing process. The polishing process exposes the flat upper surfaces of the pedestals and creates a smooth planar surface across the pedestals and the dielectric layer. The second dielectric layer is constructed of an electrically insulating, thermally conducting material, and extends laterally across the substrate beyond the first pole to provide an effective heat sink. 
     Upon the smooth surface of the second dielectric layer the coil is formed, including a pair of contacts at the inner and outer ends of the coil. An insulation layer is deposited over the coil and formed so as to not cover the back gap or write gap pedestal. In addition, the insulation layer is formed with openings called “vias” at the location of the contacts of the coil. A thin layer of electrically insulating, non-magnetic material is then deposited over the insulation layer and over the write gap pedestal. Again, the write gap material is formed so that it does not cover the back gap pedestal or the contacts of coil, although it does cover the write gap pedestal. 
     To complete the read/write head, the second pole is formed over the first pole. The back of the second pole contacts the back gap pedestal of the first pole, and the front of the second pole sits atop the write gap material above the write gap pedestal of the first pole. 
     In use, when a voltage is applied to the contacts of the coil, a current will flow through the coil. This current will generate heat according to the formula W=I 2 R, where W is the heat generated per second, I is the current flowing through the coil, and R is the resistance of the coil. The heat generated by the coil will flow through the thermally conductive second dielectric layer. The heat will be conducted out of the yoke through this dielectric layer and dissipated so that it will not affect the read performance of the read/write head. 
     These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following descriptions of the invention and a study of the several figures of the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, with like reference numerals designating like elements. 
     FIG. 1A is a partial cross-sectional front elevation view of a magnetic data storage system; 
     FIG. 1B is a top plan view taken along line  2 B— 2 B of FIG. 2A; 
     FIG. 2A is a cross-sectional view of a background art read/write head of the magnetic disk dive assembly of FIG. 1A and 1B; 
     FIG. 2B is a plan view taken along line  2 B— 2 B of FIG. 2A; 
     FIG. 2C is an ABS view taken along line  2 C— 2 C of FIG. 2A; 
     FIG. 2D is a representative graph of a relationship between yoke length and flux rise time; 
     FIG. 3 is a process diagram of a method for forming a write element of the background art; 
     FIG. 4 is a cross sectional view of a read write head of the present invention taken along line  4 — 4  of FIG. 1B shown expanded and rotated 110 degrees clockwise. 
     FIG. 5 is an expanded view taken from region  5  of FIG. 4; 
     FIG. 6 is a plan view taken from line  6 — 6  of FIG. 4; 
     FIG. 7 is a view similar to view  5  of an alternate embodiment of the invention; 
     FIG. 8 is a view similar to view  5  of an alternate embodiment of the invention; 
     FIG. 9 is a process diagram of a method for forming a read/write head of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 4, and more particularly to FIG. 5, the present invention is embodied in a magnetic read/write head, generally referred to as  500 , for use in a magnetic disk data storage system  10  (FIGS.  1 A and  1 B). FIG. 4 shows a cross sectional view of a read/write head  400  of the present invention. FIG. 5 shows an expanded view taken from region  5  of FIG.  4 . With reference to FIG. 5 the read/write head  500  includes a read element  502  and a write element  504  disposed atop a ceramic substrate  506 . As with the prior heads of the background art, the read element  502  of the read/write head  500  includes a first dielectric layer  508  sandwiched between first and second shields  510  and  512 . The read element further includes a read sensor  514  embedded within the first dielectric layer  508  between the first and second shields  510  and  512 . 
     With continued reference to FIG. 5, the write element  504  includes the second shield  512  which serves as a portion of a first pole  518  and has a planar upper surface  515 . A second pole  520  joins with the first pole  518  to form a yoke  521  having a write gap portion  516  and a back gap portion  517 . A write gap pedestal  522 , located in the write gap portion  516  extends upward from the planar upper surface  515 . Similarly, a back gap pedestal extends upward from the planar upper surface in the back gap portion  517 . The write gap pedestal  522  and the back gap pedestal  524  each have flat upper surfaces  526  and  528  respectively which are coplanar across a plane  530 . 
     With reference to FIGS. 5 and 6, a second dielectric layer  532  covers the first pole  518 , surrounding the pedestals  522  and  524 . As shown more clearly in FIG. 6, the dielectric layer extends laterally beyond the first pole  518 . The second dielectric layer is planarized by a chemical mechanical polish (CMP) process which gives it a smooth, flat upper surface  534  which is coplanar with the plane  530  and flush with the upper surfaces  526  and  528  of the pedestals  522  and  524 . The second dielectric layer  532  is constructed of a material which is both an electrical insulator and a thermal conductor. The thermal conductivity of the dielectric layer should be at least twice that of alumina (Al 2 O 3 ), preferably the thermal conductivity should be at or above 24 W/m o K at 40° Celsius and at or above 65 W/m o K at 20° Celsius. While several materials could provide the necessary electrical resistance and thermal conductance, in the preferred embodiment the dielectric layer is constructed of Al 3 N 4 , deposited by a reactive ion sputtering process. Alternatively, the second dielectric layer  532  could be constructed of Si 3 N 4 , or of Si 3 O 3 . The deposited planarized dielectric layer  532  has a thickness t which should be within the range of ½ to 1{fraction (-1/2)} microns and is more preferably between 1 and 1{fraction (-1/2)} microns. 
     A coil  536  is formed on top of the second dielectric layer such that a portion of the coil passes through the yoke  521  between the first and second poles  518  and  520  and between the write gap and back gap pedestals  522  and  524  respectively. While the coil  536  could be formed of any suitable conductive material, it is preferably formed of copper (Cu). The coil  536  includes a plurality of winds  538  which define a pitch p, defined as the distance from an edge of a wind to the corresponding edge of an adjacent wind. Each wind has a wind thickness Tw. With reference to FIG. 6 the coil terminates at its inner and outer ends in first and second contacts  540  and  542  respectively. 
     An insulation layer  541  covers the coil  536  and electrically isolates it from the surrounding structure as well as isolating the winds  538  from one another. The insulation layer  541  is preferably a photoresist which can be spun onto the coil  536  and the dielectric layer  532  and then cured. The insulation layer  541  will be deposited over the entire structure formed thus far. The photoresist will then be locally masked and lifted off in order to expose the write gap and back gap pedestals  522  and  524  and also to provide vias at the locations of the contacts  540  and  542  (FIG.  6 ). Once cured, the insulation layer  540  will define a gradually sloping edge  544  at the write gap portion. This gradually sloping edge will be beneficial in defining a low apex angle as will be described in more detail below. 
     The insulation layer  541  is covered with a thin layer of write gap material  546  which extends over and covers the upper surface  526  of the write gap pedestal  522 , thereby separating the first and second poles  518  and  520  in the write gap portion  516  of the yoke  521 . The write gap material can be formed of any suitable non-magnetic, electrically insulating material, such as alumina. The write gap material layer  546  is formed so as not to cover the back gap pedestal  524 . In addition, with reference to FIG. 6, the write gap material  546  is formed to leave vias at the locations of the first and second contacts  540  and  542 . 
     Completing the write element  504  of the present invention, the second pole  520  is formed over the write gap material layer  546  and also over the back gap pedestal  524  of the first pole, whereby the first and second poles,  518  and  520 , together form the yoke  521 . At the write gap portion  516  of the yoke  521 , the second pole  520  sits atop the write gap material  546  which in turn sits atop the write gap pedestal  522 . The space between the first and second poles  518  and  520  in the write gap portion  526  defines a write gap  544 . 
     During use of the constructed read/write head  500 , an electrical current will be conducted through the coil  536  as supplied from the contacts  540  and  542  in order to generate a magnetic field as described in above in the background of the invention. The resistance inherent in the coil  536  will cause the electrical current to generate heat according to the formula W=I 2 R, where W is the amount of heat generated per second, I is the current flowing through the coil and R is the electrical resistance of the coil. In order to maintain a short yoke length YL, the number of winds  538  and the wind thickness Tw must be limited. However with a reduced wind thickness Tw the resistance of the coil increases. In addition, limiting the number of coils requires an increase in current in order to maintain a given magneto-motive force. Both of these factors increase the heat generated by the coil. This heat is problematic for multiple reasons. 
     First, the heat will cause thermal stresses in the read write/head  500  as the various materials of which it is made expand at different rates. These thermal stresses will cause magnetic domain pattern reconstruction due to the magnetostriction of the magnetic materials used in the head. The magnetic domain movement in the shields will generate magnetic flux which passes through the read sensor. For a high sensitivity MR head, this undesired magnetic flux will be interpreted as a magnetic signal. 
     The second problem created by the heat generation is that the heat itself when conducted to the read sensor, will degrade the performance of the read sensor  514 . Such degradation of read properties is called “Johnson Thermal Noise”, and is proportional to (ω)(K B T)(R) where ω is the frequency of the signal being read, K B T is the temperature of the sensor in degrees Kelvin and R is the resistance of the sensor. 
     However, the present invention alleviates the effects of this heat generation. The high thermal conductivity of the second dielectric layer  532  on which the coil  536  sits conducts heat away from the coil before that heat can be conducted through to the shield  512  and to the read sensor  514 . With reference to FIG. 6, the thermally conductive dielectric layer  534  extends laterally far beyond the yoke  521  and therefore provides a very large heat sink for dissipation of the heat from the coil. In other words, heat generated by the coil  536  will conduct into the dielectric layer  532  and out of the yoke  521  into regions of the read/write head  500  remote from the read sensor  514 . This dissipation will also prevent thermal stresses on the read/write head  500 . In order to optimize this thermal performance as well as the overall performance of the head  500  it has been found that the read sensor  514  should preferably be a distance of 3-3 ½ microns between the read sensor  514  and the write gap  516  of the write element  504 . 
     With reference now to FIG. 9, a method  900  of manufacturing a read/write head of the present invention will now be described. In a step  902  the substrate  506  is provided. The substrate is constructed of a ceramic material and is planarized to have a smooth flat upper surface. In a step  903 , the first shield  510  is formed on top of the ceramic substrate  506 . Then, in a step  904  the first dielectric layer  508  is formed and the read sensor  514  embedded therein. Thereafter, in a step  906  the second shield  512  is formed over the first dielectric layer  508  and the first dielectric layer further built up to at least the top of the second shield  512 . Then, in a step  908 , the shield and built up dielectric layer are planarized by a CMP process which creates a smooth flat surface across the top of the shield  512  and the dielectric layer  508 . 
     With the read element  502  constructed, the write element  504  can be formed using the shield  512  as a portion of the first pole  518 . In a step  910 , the write gap and back gap pedestals  522  and  524  are built up on top of the smooth, planar upper surface of the second shield  512  to form the first pole. The pedestals  522  and  524  can be constructed of a magnetic material such as Ni 20 Fe 80 . Alternatively, the pedestals  522  and  524  can be constructed of a high Magnetization material such as Ni 45 Fe 55 . Use of such high Magnetization materials can increase the magnetic performance of the write head, however such materials present manufacturing challenges due to their highly corrosive nature. 
     In a step  912 , the second dielectric layer is formed on top of the first pole  518 , covering the pedestals  522  and  524 . As shown more clearly with reference to FIG. 6, the second dielectric layer  532  extends beyond the first pole  518  to cover the first CMP dielectric layer  512 . This second dielectric layer  532  should be constructed of an electrically insulating, thermally conductive material. While this second dielectric layer  532  could be constructed of any suitable thermally conductive, dielectric material, it is preferably constructed of Al 3 N 4  and deposited by a reactive sputtering process. The second dielectric layer  532  could also be constructed of Si 3 N 4  and deposited by a chemical vapor deposition (CVD) process or constructed of Si 3 O 3  deposited by either sputtering or CVD. Then in a step  914 , the second dielectric layer  532  is planarized by a CMP process which exposes the upper surfaces  526  and  528  of pedestals  522  and  524  respectively. The CMP process is conducted sufficiently to generate smooth, flush, flat surfaces  526 ,  524  and  534  along the plane  530 . 
     Thereafter, in a step  916 , the coil  536  is formed on top of the second dielectric layer  532 . First, a layer of copper seed is deposited to provide a conductive surface on which to plate the copper coil. Then with the seed deposited, the copper coil is plated using photolithography to provide the desired shape. Once the coil has been plated, the remaining, exposed seed layer can be removed by an etching process. Then in a step  918 , the insulation layer  541  can be formed. The insulation layer  541  is deposited as a photoresist which is spun onto the structure. The photoresist is masked, and lifted off to expose the pedestals  522  and  524  and to provide vias for the contacts  540  and  542 . The insulation layer is cured by thermal treatment in a furnace which solidifies the photoresist and causes it to have a gently sloped angle at its termination adjacent to the write gap pedestal  526 . 
     In a step  920  the write gap material layer  546  is deposited. While the write gap material can be of any suitable non-magnetic, electrically insulating material, the write gap material is preferably alumina (Al 2 O 3 ). After deposition, the write gap material layer can be etched to expose the back gap pedestal  524  and to provide a via at the locations of the contacts  540  and  542 . To complete the read/write head  500 , in a step  922  the second pole  520  is formed over the write gap material  546  and over the back gap pedestal  524 . The second pole  520  is preferably formed of Ni 20 Fe 80  and deposited by plating as understood by those skilled in the art. Alternatively, the second pole can be formed of a high Magnetization material such as Ni 45 Fe 55  and deposited by plating. The gradual slope  544  of the insulation layer  541  in the write gap portion  516  will cause the pole to define a low apex angle  546 . This low apex angle improves the magnetic flux flow at the write gap portion  516  of the yoke  521 , and allows the second pole to be formed with a more tightly controlled track-width. 
     With reference to FIG. 7, in an alternate embodiment of the invention  700  a single dielectric material matrix  702  contains the read element  514  and serves as a substrate for the coil  536 . In this embodiment, the entirety of the dielectric material  702  consists of a thermally conductive, electrically insulating material. As with the preferred embodiment, such a material could be Al 3 N 4 , Si 3 N 4 , or Si 3 O 3 . Such a design would provide an increased heat sink for dissipation of heat from the coils. While certain head designs might require such an additional heat dissipation, this embodiment would also increase manufacturing costs due to the increased use of the thermally conductive materials. 
     With reference to FIG. 8, another embodiment  800  is provided which could be considered a hybrid of two of the previously described embodiments. In this embodiment, a first dielectric layer  802  is constructed of an electrically insulating material such as alumina Al 2 O 3  as with the preferred embodiment. However, rather than extending to the top of the first shield, the first dielectric layer  802  extends only to the bottom of the second shield  510 . In this way, when the second dielectric is formed, it will have an increased thickness  806  in the region beyond the yoke  521 . The second insulation layer  804  is constructed of a thermally conductive material as described in the preferred embodiment, however the increased thickness of the second dielectric layer  804  in the region outside of the yoke provides a larger heat sink, providing increased heat dissipation. While this embodiment entails increased manufacturing costs over the preferred embodiment it will not be as expensive as the embodiment illustrated in FIG. 7 which includes thermally conductive dielectric material  702  in both the read  502  and write  504  portions of the head. 
     In yet another embodiment of the invention, not shown, the write gap material layer can be deposited over the coil rather than over the insulation layer. Similarly, the write gap material could be deposited over the second dielectric layer in which case the coil and insulation layer would be formed on top of the write gap material. 
     From the above it can be appreciated that the present invention provides a write head, and a method of manufacturing same, which solves the problems of heat generation inherent in high data rate read write heads. The present invention effectively conducts away and dissipates heat while incurring little additional manufacturing expense. While the invention has been described herein in terms of several preferred embodiments, other embodiments of the invention, including alternatives, modifications, permutations and equivalents of the embodiments described herein, will be apparent to those skilled in the art from consideration of the specification, study of the Figures, and practice of the invention. Therefore, the embodiments and preferred features described above should be considered exemplary, with the invention being defined by the appended claims, which therefore include all such alternatives, modifications, permutations and equivalents as fall within the true spirit and scope of the present invention.