Abstract:
The presently disclosed technology describes systems and methods for attaining a ball bond using less than 1 thousandth of an inch diameter gold wire using ultrasonic bonding energy and without heating an underlying bonding pad. The ball bond allows the use of particularly small bonding pads that are particularly close to adjacent microelectronic structures that limit the use of other bonding techniques that have shallow take-off angles.

Description:
BACKGROUND 
     Wire bonding is a method of making electrical interconnections among bonding pads, such as those located on an integrated circuit (IC) device and/or a printed circuit board (PCB) during semiconductor and/or storage device fabrication. Further, wire bonding can be used to connect an IC to other electronics or to connect from one PCB to another. Wire bonding is generally considered a cost-effective and flexible interconnect technology, which is used to assemble a wide variety of semiconductor packages. There are two main classes of wire bonding, wedge bonding and ball bonding. Both wedge bonding and ball bonding are typically accomplished using a combination of heat, compressive force, and ultrasonic energy to bond a wire to one or more bonding pads. 
     Wedge bonding is typically carried out at room temperature, but has several limitations. First, the take-off angle and direction are substantially limited. Second, the wedge bond creates a relatively large foot size. Third, additional wedge bonds may not be stacked on top of a previous bonded spot on a bonding pad. As a result, wedge bonding is not an available options in applications with very small bonding pads or when an extruded object is in front of the take-off direction of the wedge bonded wire. Further, the bonded spot may not be reused due to oxidation (e.g., when an aluminum alloy wire is used), which could become a problem when the size of the bonding pad size is small and rewiring is necessary. 
     As distinct from wedge bonding, ball bonding typically heats the bonding pad to create the bond. However, heating the bonding pad may not be an available option due to the heat potentially damaging sensitive IC devices adjacent the bonding pad or other components of the IC (e.g., adhesives). Ball bonding has several advantages over the wedge bond, such as more flexibility in take-off direction and angle from the bonding pad without inducing unacceptable stresses on the bond, greatly reduced bonding size, and ball-on-ball stacking capability. 
     SUMMARY 
     A method comprising ball bonding a less than about 1 thousandth of an inch in diameter gold alloy wire to a gold alloy contact pad at about ambient temperature and using a ultrasonic bonding frequency greater than 60 kHz and less than 200 kHz. 
     Other implementations are also described and recited herein. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  illustrates an example disc drive assembly including a ball bond remnant on a bonding pad of a slider located at a distal end of an actuator arm and positioned over a storage media disc. 
         FIG. 2  illustrates a side view of an example lapping carrier assembly that includes a slider row bar ball bonded to a printed circuit board. 
         FIG. 3  illustrates a top view of an example lapping carrier assembly that includes a slider row bar with one pair of bonding pads ball bonded to a corresponding pair of bonding pads on a printed circuit board. 
         FIG. 4  illustrates a side view of an example lapping carrier assembly that includes a slider row bar ball bonded to a printed circuit board with an air-bearing surface of the slider row bar lapped co-planar with a planarization sensor embedded within the slider row bar. 
         FIG. 5  illustrates a side view of an example slider row bar with a ball bond remnant attached thereto. 
         FIG. 6  illustrates a perspective view of an example lapping carrier assembly that includes an example slider in a row bar ball bonded to a printed circuit board. 
         FIG. 7  illustrates example operations for using ball bonding to form wire interconnections between contact pads on a slider row bar and contact pads on a PCB without heating the contact pads on the slider row bar. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an example disc drive assembly  100  including a ball bond remnant  116  on a bonding pad  118  of a slider  120  (e.g., an AlTiC slider) located at a distal end of an actuator arm  110  and positioned over a storage media disc  108 . Referring specifically to View A (x-y plane), the disc  108  includes an outer diameter  102  and an inner diameter  104 , between which are a number of substantially circular data tracks (e.g., track  106 ) illustrated by circular dotted lines. In some implementations, there are more data tracks than illustrated in  FIG. 1 . The disc  108  rotates at a high speed about a disc axis of rotation  112  as information is written to and read from the data tracks on the disc  108 . The disc rotation speed may be fixed or variable. 
     Information may be read from or written to the disc  108  through the use of read/write elements on the slider  120 , which is located at a distal end of an actuator arm  110 . The actuator arm  110  rotates about an actuator axis of rotation  114  during a seek operation to locate a desired data track and sector on the disc  108 . Specific locations on the media disc  108  may be defined by any available addressing scheme (e.g., cylinder-head-sector (CHS) addressing and logical block addressing (LBA) schemes). The actuator arm  110  extends toward the disc  108  and the slider  120  is located at the distal end of the actuator arm  110 . The slider  120  flies in close proximity above the disc  108  while reading and writing data to the disc  108 . In other implementations, there is more than one slider  120 , actuator arm  110 , and/or disc  108  in the disc drive assembly  100 . 
     A flex cable  122  provides the requisite electrical connection paths from a printed circuit board (PCB, not shown) to electronic components attached to the slider  120  (e.g., a read element and a write element), while allowing pivotal movement of the actuator arm  110  during operation. The flex cable  122  may be routed along the actuator arm  110  from the PCB to the slider  120 . The PCB may include circuitry (e.g., a preamplifier (preamp)) for controlling the write currents applied to the write element during a write operation and amplifying read signals generated by the read element during a read operation). 
     A side view of a trailing edge of the slider  120  is shown in detail in View B of the x-z plane of  FIG. 1 . The slider  120  includes the bonding pad  118  (e.g., an electronic lapping guide (ELG) bonding pad with the ball bond remnant  116  attached thereto. The ball bond remnant  116  is a remnant from a wire previously ball bonded to the bonding pad  118 . In some implementations, the ball bond remnant  116  is removed (e.g., by mechanically shaving it off of the bonding pad  118 ). Further, the slider  120  may include additional bonding pads and ball bond remnants (not shown) behind the bonding pad  118  and the ball bond remnant  116  in the negative y-direction. 
     The slider  120  may further include a microelectronic component  126  protruding from the slider  120  (e.g., a laser in a heat assisted magnetic recording (HAMR) device). In one implementation, the wire previously ball bonded to the bonding pad  118  is intentionally routed around the microelectronic component  126  to avoid contact with the protruding microelectronic component  126  as shown in detail in  FIGS. 2 and 4 . Further, the slider  120  may include additional microelectronic components (not shown) behind the microelectronic component  126  in the negative y-direction. 
     The slider  120  further includes a planarization sensor  140  (also referred to as an “electronic lapping guide” or “ELG”) embedded within. The planarization sensor  140  electrically connects at least two bonding pads together within the slider  120 . A cross-sectional area in the y-z plane of the planarization sensor  140  defines a resistive value of the planarization sensor  140  between the least two bonding pads. Prior to forming the air bearing surface (ABS)  130 , the slider  120  is planarized (e.g., using lapping and/or chemical-mechanical polishing (CMP)), the y-z cross-sectional area of the planarization sensor  140  shrinks and its resistive value increases. The resistive value of the planarization sensor  140  can be measured and used to determine the amount of material removal on the ABS  130 . As a result, planarization of the ABS  130  can be precisely controlled using the measured resistive value of the planarization sensor  140  and built-in actuators in a lapping carrier (not shown). 
     An air-bearing  128  caused by aerodynamic forces is created between the ABS  130  of the slider  120  and a top surface of the disc  108  when the disc  108  is in motion. The ABS  130  of the slider  120  faces the disc  108  surface and is approximately parallel to the disc  108  surface (i.e., both are approximately in the x-y plane. As a result, no portion of the slider  120  substantially protrudes beyond the ABS  130  toward the disc  108  surface. An example process for creating this substantially smooth surface is described in detail with respect to  FIGS. 2-5  below. 
     The appearances of the slider  120  and other features of assembly  100  are for illustration purposes only and not drawn to scale. Further, the presently disclosed ball bonding technology may apply to storage drive assemblies other than the disc drive assembly  100  depicted in  FIG. 1 . Still further, the presently disclosed technology may be used to ball bond wires to microelectronic devices other than sliders used in devices other than electronic storage devices. 
       FIG. 2  illustrates a side view of an example lapping carrier assembly  200  that includes a slider row bar  232  ball bonded to a printed circuit board  234 . The assembly  200  is used to obtain an accurately planarized and highly smooth (e.g., sub-nanometer variations) surface which will be patterned to form an air-bearing surface (ABS) (not shown, see  FIGS. 1 ,  4 , and  5 ). The row bar  232  includes a row of sliders (e.g., slider  124  of  FIG. 1 ) for inclusion in a storage drive assembly (e.g., disc drive assembly  100  of  FIG. 1 ), for example. In other implementations, the row bar  232  includes a row of microelectronic devices other than sliders. 
     The row bar  232  is releasably bonded to a lapping carrier  236  using an adhesive  238  (e.g., a wafer grip or adhesive). The row bar  232  includes a microelectronic component  226  protruding from the row bar  232 . In one implementation, the microelectronic component  226  is a laser in a heat assisted magnetic recording (HAMR) device. The row bar  232  further includes the bonding pad  218 , which provides an electrical connection to a planarization sensor  240  embedded within the row bar  232 . The planarization sensor  240  is discussed in more detail with reference to  FIGS. 3 and 4 . In various implementations, the bonding pad  218  may be made of or coated with gold or metallic alloys. In one implementation, the bonding pad  218  is quite small (e.g., 127 μm×85 μm or 50 μm×50 μm square) and has a less than 1 micron thick (e.g., 0.25 microns thick) gold coating layer. 
     The PCB  234  includes a PCB bonding pad  242 , which provides an electrical connection to the PCB  234 , which in turn may connect to a lapping control unit that monitors and adjusts lapping operations on the row bar  232  in real time. The PCB  234  is connected to the row bar  232  via an electric trace  244  (or wire) connecting the bonding pads  218 ,  242 . In various implementations, the trace  244  may be made of a gold or copper alloy. The PCB  234  may be mounted in any location and orientation with respect to the row bar  232  that is convenient. In one example implementation, a planar bonding surface of the PCB bonding pad  242  is mounted at an angle (e.g., approximately 5 degrees) with respect to a planar bonding surface of the bonding pad  218  (e.g., the y-z plane) and is mounted to a top surface of the assembly  200  (not shown) via a strip of double-stick tape or a mechanical lock, for example. 
     In this implementation, one end of the trace  244  is ball bonded to the bonding pad  218  (as depicted by ball bond  216 ). The ball bond is used in lieu of a wedge bond for several reasons. One, the takeoff angle of the wedge bond is limited to a relatively shallow angle from the bonding pad surface (e.g., less than 45 degrees) and a direction generally in the x-z plane (based on the orientation of a foot of the wedge bond). Due to the proximity of the bonding pad  218  to the microelectronic component  226  protruding from the row bar  232  and the relative height in the negative x-direction of the microelectronic component  226  protruding from the row bar  232 , such a shallow takeoff angle in a general direction of the PCB  234  may not be possible without colliding with the microelectronic component  226 . Further, the foot of the wedge bond may be too large to accommodate the small size of the bonding pad  218  and/or the wedge bond may render the bonding pad  218  unusable for later electrical connections without additional processing of the bonding pad  218  surface. 
     However, ball bonding typically requires heat to be applied to the bonding pad  218  to create a sufficiently strong bond to the trace  244 . In many implementations, the temperature of the bonding pad  218  would exceed 125 degrees Celsius to form a sufficiently strong bond. This relatively high temperature may cause the adhesive  238  to melt or become soft, which could cause the row bar  232  to become loose or detached from the carrier  236 , especially if and when any shear force is applied to the row bar  232  generally in the x-direction. In addition, thermal cycling the lapping carrier assembly  200  may alter the adhesive&#39;s mechanical properties and induce additional stress and strain to the assembly  200 , which can deform the assembly  200  and negatively impact lapping performance. 
     In order to ball bond without thermally cycling the assembly  200 , a ball bonding tool (not shown) may apply ultrasonic energy (e.g., 120 kHz) and compressive force (e.g., 0.2N using a 0.8 mil diameter gold wire) to bond the trace  244  to the bonding pad  218  without heating the bonding pad  218 . Utilizing a high ultrasonic frequency (e.g., 120 kHz over 60 kHz) and properly scrubbing the bonding pad  218  to clean the bonding pad  218  enhances the energy transfer efficiency and interatomic movement during the bonding of the trace  244  to the pad  218 . As a result, the trace  244  may be bonded to the pad  218  without applying any heat directly to the bonding pad  218 . In other words, the trace  244  may be bonded to a relatively cool bonding pad  218  (e.g., at ambient or room temperature). More specifically, ambient temperature is referred to herein as ranging from about 15-25 degrees Celsius). In other implementations, the ball bonding process described herein may be performed successfully with the bonding pad  218  between 18-30 degrees Celsius or between 15-50 degrees Celsius. In an example implementation, the ultrasonic frequency applied to form trace  244  is approximately 120 kHz and the trace  244  is primarily gold with an approximately 0.7 mil diameter. In other implementations, the ultrasonic frequency applied to the trace  244  ranges from above 60 kHz to below 200 kHz. 
     An opposite end of the trace  244  is stitch bonded to the bonding pad  242 . In other implementations, the trace  244  is ball bonded to the bonding pad  242  and stitch bonded to the bonding pad  218 . 
     In one implementation, the trace  244  diameter is less than about 1 thousandth of an inch in diameter of a gold alloy wire. The trace  244  may be less than about 1 thousandth of an inch in diameter in order to yield a ball bond with a size (e.g., cross-sectional area) significantly smaller than the contact pad  218  surface area. For example, a 0.7 thousandths of an inch trace may yield a ball bond approximately 33 μm in diameter on a 60 μm×60 μm contact pad. As the trace  244  diameter becomes smaller, ball bonding the trace  244  to a contact pad without applying thermal energy rapidly becomes more difficult. 
     First, the transfer of ultrasonic energy in ball bonding become less efficient with decreasing trace  244  diameter due to an increasing disparity between a fixed ultrasonic energy of the bonding tool (e.g., 120 kHz) and the rapidly increasing resonant frequency associated with the ball at the end of the trace  244 . The increasing resonant frequency is proportional to 1/√{square root over (m)}, where m represents the mass of the ball at the end of the trace  244 . As the mass approaches zero, the resonant frequency approaches infinity. Second, as the trace  244  diameter decreases, the trace  244  is more susceptible to breaking, which renders the trace  244  increasingly difficult to handle and susceptible to breakage. Even with 0.5 mil diameter gold wire, the trace  244  becomes extremely fragile and is therefore extremely difficult to perform consistent ball bonding using such a small diameter wire. As a result, ball bonding a trace  244  less than about 1 mil (e.g., 0.7 mil) in diameter is far less efficient in energy transfer and therefore much more challenging than ball bonding a trace between 1 mil and 2 mil, or greater, in diameter. 
     Further, as discussed above, the ultrasonic energy used to ball bond the trace  244  should match the resonant frequency of the trace  244  ball within an acceptable tolerance to maximize the energy transfer to the ball and pad  218 . Applying the ultrasonic energy to the trace  244  becomes more difficult as the resonant frequency increases. In one example implementation, the trace  244  resonant frequency is constrained such that a 200 kHz ultrasonic bonding frequency effectively works to create a ball bond without directly adding thermal energy at the bonding pad  218 . In other implementations, a 120 kHz ultrasonic bonding frequency effectively works to ball bond a 0.7 mil diameter trace without heating the trace. Other ultrasonic bonding frequencies are contemplated herein. 
       FIG. 3  illustrates a top view of an example lapping carrier assembly  300  that includes a slider  324  in a row bar  332  with a pair of bonding pads  318 ,  319  ball bonded to a corresponding pair of bonding pads  342 ,  343  on a printed circuit board  334 . The row bar  332  includes a row of sliders (e.g., the slider  324 ), each of which may be included in a storage drive assembly (e.g., disc drive assembly  100  of  FIG. 1 ) or other electronic device. In other implementations, the row bar  332  includes a row of microelectronic devices other than sliders. 
     After ABS patterning, the individual sliders may be separated by dicing the row bar  332  using dicing lanes (e.g., dicing lane  348 ). The depicted row bar  332  includes six separate sliders, although other implementations may include greater or fewer numbers of separate sliders. In one example implementation, the row bar includes 62 separate functional sliders and two non-functional (or “dummy”) sliders at each end of the row bar. While slider  324  is discussed with specificity with reference to  FIG. 3 , any one or more of the other depicted sliders may be used in a similar manner. 
     The row bar  332  is releasably bonded to a carrier  336  using an adhesive  338 . The slider  324  includes a microelectronic component  326  protruding from the row bar  332  (in the negative x-direction). In one implementation, the microelectronic component  326  is a laser for use in a heat assisted magnetic recording (HAMR) device. The slider  324  further includes bonding pads (e.g., bonding pads  318 ,  319 ), each of which may provide an electrical connection to a planarization sensor (not shown) embedded within the slider  324 . Here, the slider  324  is depicted with two bonding pads for real-time in-situ monitoring and control of a lapping process, although other implementations may have greater or fewer numbers of bonding pads with varied functionality. 
     The PCB  334  includes PCB bonding pads (e.g., PCB bonding pads  342 ,  343 ), each of which provides an electrical connection to the PCB  334  (e.g., to a lapping control unit (not shown) on or electrically connected to the PCB  334 ). Here, the PCB  334  is depicted with 12 PCB bonding pads, although other implementations may have greater or fewer numbers of PCB bonding pads. The PCB  334  is connected to the slider  324  via electric traces or wires. For example, bonding pad  318  is connected to PCB bonding pad  342  via electric trace  344  and bonding pad  319  is connected to PCB bonding pad  343  via electric trace  345 . Here, two electric traces are depicted, although other implementations may have greater or fewer numbers of electric traces. The PCB  334  may be mounted in any location and orientation with respect to the row bar  332  that is convenient. 
     The slider  324  further includes a planarization sensor  340  embedded within (illustrated by dotted lines). The planarization sensor  340  electrically connects to the bonding pads  318 ,  319  on the slider  324 . A cross-sectional area of the planarization sensor  340  is proportionally related to a resistive value of the planarization sensor  340 . As the slider  324  is planarized (e.g., using lapping and/or chemical-mechanical polishing (CMP)), the cross-sectional area of the planarization sensor  340  decreases as its resistive value increases. A resistance value of the planarization sensor  340  correlates to the amount of material removal at the lapping surface of the slider  324 . As a result, the slider  324  surface can be precisely planarized using the measured resistive value of the planarization sensor  340 . 
     In this implementation, the traces  344 ,  345  are ball bonded (see e.g., ball bond  316 ) to the bonding pads  318 ,  319 , respectively. The ball bond is used in lieu of a wedge bond for several reasons. One, the takeoff angle of the wedge bond is limited to a relatively shallow angle from the bonding pad surface (e.g., less than 45 degrees) and a direction generally in the x-z plane (based on the orientation of a foot of the wedge bond). Due to the close proximity of the bonding pads  318 ,  319  to the microelectronic component  326  protruding from the row bar  332  and the relative height in the negative x-direction of the microelectronic component  326  protruding from the row bar  332 , such a shallow takeoff angle in a general direction of the PCB  334  may not be possible without colliding with the microelectronic component  326 . Further, the foot of the wedge bond may be too large to accommodate the small size of the bonding pad  318  and/or the wedge bond may render the bonding pad  318  unusable for later electrical connections without additional processing of the bonding pad  318  surface. 
     However, ball bonding typically requires heat to be applied to the bonding pad  318  to create a sufficiently strong bond to the trace  344 . In many implementations, the temperature of the slider  324  would exceed 125 degrees Celsius to create a sufficiently strong bond. This high temperature may cause the adhesive  338  to melt or become soft, which may cause the row bar  332  to become loose or detached from the carrier  336 , especially if and when any shear force is applied to the bonding pad  318  or other component of the row bar  332  generally in the x-direction. In addition, the thermally cycling the assembly  300  may alter the adhesive&#39;s mechanical properties and induce additional stress and strain to the assembly  300 , which can deform the assembly  300  and negatively impact lapping performance and/or the output specifications for the row bar  332 . 
     In order to ball bond without thermally cycling the assembly  300 , a ball bonding tool (not shown) may apply a relatively high frequency ultrasonic energy and compressive force with proper scrubbing of the bonding pad surfaces to bond the traces  344 ,  345  to the bonding pads  318 ,  319 , respectively. The relatively high frequency ultrasonic signal reduces the energy gap between the ultrasonic frequency and the ball bond&#39;s resonant frequency, thereby enhancing the efficiency of ultrasonic energy transfer during bonding of the traces  344 ,  345  to the pads  318 ,  319 . As a result, the traces  344 ,  345  may be bonded to the pads  318 ,  319  without applying any thermal energy directly to the bonding pads  318 ,  319  and while the bonding pads  318 ,  319  are generally maintained at room temperature with no thermal energy directly applied to the bonding pads  318 ,  319 . 
     An opposite end of each of the traces  344 ,  345  is stitch bonded to the PCB  334  at bonding pads  342 ,  343 . In other implementations, the traces  344 ,  345  are ball bonded to the bonding pads  342 ,  343  and stitch bonded to the bonding pads  318 ,  319 . 
       FIG. 4  illustrates a side view of an example lapping carrier assembly  400  that includes a slider row bar  432  ball bonded to a printed circuit board  434  with an air-bearing surface  430  of the slider row bar  432  lapped co-planar with a planarization sensor  440  embedded within the slider row bar  432 . The planarization assembly  400  is used to precisely lap the slider row bar  432  to obtain an accurately planarized and highly smooth air-bearing surface  430  of the row bar  432 . The row bar  432  includes a row of sliders (e.g., slider  124  of  FIG. 1 ) for inclusion in a storage drive assembly (e.g., disc drive assembly  100  of  FIG. 1 ), for example. In other implementations, the row bar  432  includes a row of microelectronic devices other than sliders. 
     The row bar  432  is releasably bonded to a carrier  436  using an adhesive  438 . The row bar  432  includes microelectronic components (e.g., microelectronic component  426 ) protruding from the row bar  432 . In one implementation, the microelectronic component  426  is a laser in a heat assisted magnetic recording (HAMR) device. The row bar  432  further includes bonding pads (e.g., bonding pad  418 ), which provide electrical connections to the row bar  432  (e.g., specifically to the planarization sensor  440 ). 
     The row bar  432  further includes planarization sensors (e.g., planarization sensor  440  embedded within (illustrated by dotted lines). Each of the planarization sensors is electrically connected to a pair of bonding pads. For example, planarization sensor  440  is electrically connected to bonding pad  418  and a second bonding pad adjacent the bonding pad  418  (not shown) in the y-direction. A cross-sectional area (e.g., in the x-z plane) of the planarization sensor  440  defines a resistive value of the planarization sensor  440 . As an air-bearing surface  430  (ABS) is planarized (e.g., using mechanical and/or chemical-mechanical polishing (CMP)), the x-z planar area of the planarization sensor  440  decreases and its resistive value increases (see planarization sensor  240  of  FIG. 2  as compared to planarization sensor  440  of  FIG. 4 . The resistive value of the planarization sensor  440  is a measurable quantity indicating the amount of planarization at the air-bearing surface  430 . As a result, the air-bearing surface  430  can be precisely planarized using the measured resistive value of the planarization sensor  440  and built-in actuators in the lapping carrier  436 . 
     The PCB  434  includes PCB bonding pads (e.g., PCB bonding pad  442 ), which provide an electrical connections to the PCB  434  (e.g., to a lapping control unit (not shown). The PCB  434  is connected to the row bar  432  via electric traces or wires (e.g., electric trace  444 ) connecting the bonding pads. For example, electric trace  444  connects bonding pads  418 ,  442 . The PCB  434  may be mounted in any location and orientation with respect to the row bar  432  that is convenient. In this implementation, the trace  444  is ball bonded to the bonding pad  418  (as depicted by ball bond  416 ) and stitch bonded (as depicted by stitch bond  446 ) to the bonding pad  442 . In other implementations, the trace  444  is ball bonded to the bonding pad  442  and stitch bonded to the bonding pad  418 . 
       FIG. 5  illustrates a side view of an example slider  524  with a ball bond remnant  516  attached thereto. The slider  524  includes a microelectronic component  526  protruding from the slider  524  in the negative x-direction. In one implementation, the microelectronic component  526  is a laser for a laser-in-slider (LIS) heat assisted magnetic recording (HAMR) technique. The slider  524  further includes a bonding pad  518 , which provides an electrical connection to the slider  524 , and a planarization sensor  540  embedded within the slider  524 . 
     After an air-bearing surface  530  of a slider row bar (not shown, see row bar  232 ,  332 ,  432  of  FIGS. 2 ,  3 , and  4 , respectively) is adequately lapped, a printed circuit board (not shown, see PCB  234 ,  334 ,  444  of  FIGS. 2 ,  3 , and  4 , respectively) and corresponding trace(s) (not shown, see trace  244 ,  344 ,  444  of  FIGS. 2 ,  3 , and  4 , respectively) from the slider row bar to the PCB are removed. Further, the slider row bar is diced, after ABS patterning operations, into individual sliders (e.g., slider  524 ) and used as sliders in a storage drive assembly (e.g., disc drive assembly  100  of  FIG. 1 ), for example. 
       FIG. 6  illustrates a perspective view of an example lapping carrier assembly  600  that includes an example slider row bar  632  ball bonded to a printed circuit board  634 . The row bar  632  includes a row of sliders (e.g., slider  624 ), each of which may be included in a storage drive assembly (e.g., disc drive assembly  100  of  FIG. 1 ) or other electronic device. In other implementations, the row bar  632  includes a row of microelectronic devices other than sliders. After the ABS is fully patterned, the individual sliders may be separated by cutting up the row bar  632  using dicing lanes (e.g., dicing lane  648 ). Here, the row bar  632  may be separated into four separate sliders using the dicing lanes, although other implementations may have greater or fewer numbers of separate sliders. While slider  624  is discussed with specificity with reference to  FIG. 6 , any one or more of the other depicted sliders may be used in a similar manner. 
     The row bar  632  is releasably bonded to a carrier  636  using an adhesive  638 . The slider  624  includes a microelectronic component  626  protruding from the row bar  632  (in the negative x-direction). In one implementation, the microelectronic component  626  is a laser for a laser-in-slider (LIS) heat assisted magnetic recording (HAMR) device. The slider  624  further includes bonding pads (e.g., bonding pad  618 ). Here, the slider  624  is depicted with six bonding pads, four of which provide an electrical connections to planarization sensors  640 ,  641  within the slider  624 . Other implementations may have greater or fewer bonding pads, any number of which with electrical connections to the slider  624 . The planarization sensors  640 ,  641  (e.g., a reader planarization sensor  640  and a writer planarization sensor  641 ) embedded within the slider  624 . Each of the planarization sensors  640 ,  641  are electrically connected to at least two of the bonding pads and may be used to monitor planarization operations on the row bar  632  (as described in detailed above). 
     The PCB  634  includes PCB bonding pads (e.g., PCB bonding pad  642 ), each of which provides an electrical connection to the PCB  634  (e.g., to a lapping control unit (not shown)). Here, the PCB  634  is depicted with four PCB bonding pads, although other implementations may utilize a greater or fewer number of PCB bonding pads. The PCB  634  is connected to the slider  624  via electric traces or wires (e.g., electrical trace  644 ) connecting the bonding pads  618 ,  642 . Here, four electrical traces are depicted, although other implementations may utilize a greater or fewer number of traces. The PCB  634  may be mounted in any location and orientation with respect to the row bar  632  that is convenient. 
     In this implementation, the traces are ball bonded to the bonding pads on the slider  624  (as depicted by ball bond  616 ). The ball bond is used in lieu of a wedge bond for several reasons. One, the takeoff angle of the wedge bond is limited to a relatively shallow angle from the bonding pad surface (e.g., less than 45 degrees) and a direction generally in the x-z plane (based on the orientation of a foot of the wedge bond). Further, the foot of the wedge bond may be too large to accommodate the small size of the slider  624  bonding pads and/or the wedge bond may render the slider  624  bonding pads unusable for later electrical connections without additional processing of the bonding pad surfaces. 
     Ball bonding typically requires heat to be applied to the bonding pads to create a sufficiently strong bond to the traces. In many implementations, the temperature of the slider  624  would exceed 125 degrees Celsius to create a sufficiently strong bond. The high of a temperature may cause the adhesive  638  to melt or become soft, which would risk the row bar  632  becoming loose or detached from the carrier  636 , especially if and when any shear force is applied to the bonding pad  618  or other component of the row bar  632  generally in the x-direction. In addition, the thermally cycling the assembly  600  may alter the adhesive&#39;s mechanical properties and induce additional stress and strain to the assembly  600 , which can deform the assembly  600  and negatively impact lapping performance. 
     In order to ball bond without thermally cycling the assembly  600 , a ball bonding tool (not shown) may apply a relatively high frequency ultrasonic energy and compressive force with proper scrubbing on the bonding pad surfaces to clean the bonding pad surfaces to bond the traces to the bonding pads on the slider  624 . The relatively high frequency ultrasonic signal enhances the efficiency of ultrasonic energy transfer during bonding of the traces to the bonding pads on the slider  624 . As a result, the traces may be bonded to the bonding pads on the slider  624  without directly heating (e.g., applying thermal energy) to the bonding pads and while the bonding pads are generally at room temperature. 
     An opposite end of each of the four depicted traces is stitch bonded to the bonding pads on the PCB  634  (as depicted by stitch bond  646 ). In other implementations, the traces are ball bonded to the bonding pads  642  on the PCB  634  and stitch bonded to the bonding pads on the slider  624 . 
     Due to the close proximity of the four depicted traces, the ball bonds may each utilize a unique takeoff angle from the bonding pads on the slider  624  that allow the traces to extend to the PCB  634  without contacting one another. The flexible and unique takeoff angles allow the traces to extend between bonding pads with virtually any physical arrangement on the slider  624  and the PCB  634 . 
       FIG. 7  illustrates example operations  700  for using ball bonding to form wire interconnections between contact pads on a slider row bar and contact pads on a PCB without heating the contact pads on the slider row bar. Ball bonding is a type of wire bonding that may be used to make electrical interconnections as part of microelectronic device fabrication. A positioning operation  705  positions a carrier including a slider row bar and a printed circuit board within a ball bonding machine. The row bar includes a row of sliders, each of which has read and/or write heads and may be included in a storage drive assembly or other electronic device. The row bar may include contact pads (e.g., electronic lapping guide (ELG) pads) for providing electrical connections to the row bar (e.g., to planarization sensors within the row bar). The row bar is releasably bonded to a carrier using an adhesive for support and transport. 
     A decision operation  710  determines if there are unwired contact pads remaining to be ball bonded. If so, a forming operation  715  forms a ball at an end of a wire to be bonded to a contact pad on the slider row bar. The forming operation  715  may occur using an electric flame off (EFO) technique. For example, a wire is fed through a needle-like disposable tool called a capillary of a bonding machine. A high-voltage electric arc applied near the wire tip, which melts the wire at the tip of the capillary. The tip of the wire forms into a ball because of the surface tension of the molten metal. After the electric arc is applied, the molten ball at the end of the wire quickly solidifies. 
     A bonding operation  720  bonds the ball to the contact pad. In one implementation, the capillary is lowered to contact a surface of the bonding pad. The bonding machine applies ultrasonic energy and downward force that creates a bond between the ball and the bonding pad. In some implementations, the bonding pad may be plasma cleaned prior to the bonding operation  720 . In other implementations, the bonding pad is not plasma cleaned. Bonding operation  725  bonds an opposite end of the wire to a printed circuit board (e.g., using a stitch bond or other available bonding techniques). 
     Operations  710 ,  715 ,  720 ,  725  are repeated until there no remaining unwired contact pads to be ball bonded. In another implementation, the bonding operation  725  is performed after the operations  710 ,  715 ,  720  are complete. 
     A planarization operation  730  planarizes an air-bearing surface of the slider row bar. In one implementation, the printed circuit board is used to connect the planarization sensors in the row bar and the lapping control unit, which detects a resistance change of the planarization sensors due to surface lapping. The lapping control unit uses this information to control built-in actuators in the lapping carrier to exert a desired quantity of pressure from the back of the slider row bar. For example, one or more planarization sensors may be embedded within the row bar and are electrically connected to at least two of the bonding pads. A resistance value of the planarization sensors varies with the quantity of planarization applied to the row bar. In one implementation, a fixed current or voltage (i.e., an excitation signal) is applied to a pair of contact pads and a corresponding the change in voltage or current (i.e., an electric response) indicates the resistance change which corresponds to a given amount of material removal or the quantity of planarization applied to the slider row bar. This data may be fed back into the planarization operation  730  in order to achieve a desired planarization quantity. In this manner, the slider row bar may be precisely planarized. 
     Once the slider row bar is adequately planarized, removing operation  735  breaks and removes the ball bonded wires running between the slider row bar and the PCB. In one implementation, the removing operation  735  is accomplished by applying a pulse air jet to blow away the interconnecting wires between the contacts pads on the slider row bar and the printed circuit board. In other implementations, the wires are mechanically sheared off from the slider row bar. Ball bond remnants may remain on some or all of the contact pads after the ball bonded wires are removed. A continuing operation  740  continues processing of the slider row bar for patterning of ABS and dicing the fully patterned row bar into individual sliders or other microelectronic components. In one implementation, additional processes steps are preformed to give the slider row bar desired characteristics and then the slider row bar is separated into individual sliders for use in an electronic storage device or other electronic device. In one implementation, dicing lanes are provided between neighboring sliders on the row bar that are used for dicing the row bar into the individual sliders. Further, the row bar is removed from the lapping carrier and placed onto a dicing carrier before being diced into the individual sliders. 
     The logical operations making up the embodiments of the invention described herein are referred to variously as operations, steps, objects, or modules. Furthermore, it should be understood that logical operations may be performed in any order, adding and/or omitting operations as desired, unless explicitly claimed otherwise or a specific order is inherently necessitated by the claim language. 
     The above specification, examples, and data provide a complete description of the structure and use of exemplary embodiments of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. Furthermore, structural features of the different embodiments may be combined in yet another embodiment without departing from the recited claims.