Abstract:
A method and system for manufacture of a microactuator comprising a frame further including a base to connect with suspension and two moving arms to be connected parallel to said base, two piezoelectric elements to be respectively connected to said moving arm, and a slider height adjuster connecting with said moving arms to adjust the loading height of the slider.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to the micro-actuator, head gimbal assembly and hard disk drive art. Specifically, the present invention relates to the micro-actuator, head gimbal assembly and hard disk drive for a femto or lesser size magnetic head.  
       BACKGROUND OF THE INVENTION  
       [0002]     In the art today, different methods are used to improve the recording density of a hard disk drive.  FIG. 1  shows a typical disk drive. A spindle motor  102  spins the disk  101  while a drive arm (head gimbal assembly)  104  driven by voice coil motors controls the head  103  flying above the disk. Typically, voice coil motors (VCM) have been used for controlling the drive arm motion across the magnetic hard disk, which is centered around the spindle motor. In the present art, microactuators are now being used to “fine-tune” the head placement because of the inherent tolerance (dynamic play) that exists in positioning a head by a VCM alone. This enables a smaller recordable track width, which in turn increases the density or the “tracks per inch” (TPI) value of the hard disk drive.  FIG. 1   b  is an exploded view of the aforementioned elements of  FIG. 1   a.    
         [0003]      FIG. 2  provides an illustration of a microactuator as used in the art. As described in the published patent applications JP 2002-133803 and 2002-074871, a slider  202  (containing a read/write magnetic head; not shown) is utilized for maintaining a prescribed flying height above the disk surface  101  (see  FIG. 1 ).  FIG. 2   a  shows a head gimbal assembly (HGA) with a “U” shape microactuator  206  and flexure  215 . U-shaped microactuators may have two ceramic beams  203  with two piezoelectric stripes  208  on each side of the beams that are bonded at two points  204  of the slider  202  enabling the slider to have motion independent of the drive arm  104  (see  FIG. 1 ). Baseplate  216  is attached to the hinge  214 .  FIG. 2   b  shows a view of the U-shape micro actuator coupled with the head slider  202 .  FIG. 2   c  shows a side view around microactuator  206 . The suspension tongue  210  is attached to the suspension dimple  211 . There is a parallel gap between the bottom of the microactuator and the suspension tongue. The microactuator is coupled to a suspension on each side of the microactuator frame with the help of three electric conductive balls  207  (e.g., gold ball or solder ball). Four conductive balls  205  (e.g., gold ball bonding or solder bump bonding) near in the slider&#39;s trailing edge electrically couple the magnetic head and the moving plate  212  of the suspension. The head slider is directly coupled with the moving plate  212 . With expansion and contraction of the piezoelectric strip, the U-shape micro actuator  206  will deform. Consequently, this will enable the fine adjustments in positioning required of the magnetic head.  FIG. 2   d  shows another illustration using a metal frame as a micro actuator. This micro-actuator includes a base part  213  to connect with suspension and two moving arms  203  to be connected parallel to the base part. Two piezoelectric stripes  208  are mounted along the outside of the moving arms  203  to facilitate fine adjustments in position of the slider.  
         [0004]     With the rapid development of improvements in the disk drive industry, manufacturing cost becomes a very critical element. For a specific size wafer, cost is inversely proportional to quantity produced. Aside from reducing cost of production, the main consideration is reducing the size of the chips or the heads. In the current industry, the 30% size slider (pico-slider) is popular and the femto-slider (20%) is going on to mass production. In the near future, the industry may see in the introduction of a 15%, 10% or even a 5% slider. However, it is difficult to use the current U-shape micro actuator for a slider this small since the size (especially the thickness) does not match the current design requirements. Moreover, reducing the microactuator thickness to accommodate such smaller heads reduces the external shock performance of the device. Additionally, the manufacturing process for such a reduced thickness microactuator is very complicated and costly. Therefore, the industry requires a head gimbal assembly design with a uniform microactuator design that does not require any change in design during mass production in order to accommodate sliders of smaller size.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1   a - b  shows a hard disk drive as in the prior art, including a head gimbal assembly.  
         [0006]      FIG. 2  illustrates a microactuator as used in the art.  
         [0007]      FIGS. 3   a - d  show exploded and perspective views detailing an embodiment of the present invention.  
         [0008]      FIGS. 4   a - d  show exploded and perspective views detailing an embodiment of the present invention.  
         [0009]      FIGS. 5   a - d  show exploded and perspective views detailing an embodiment of present invention.  
         [0010]      FIGS. 6   a - c  show exploded and perspective views detailing an embodiment of present invention.  
         [0011]      FIGS. 7   a - c  show exploded and perspective views detailing an embodiment of present invention.  
         [0012]      FIG. 8  shows a flowchart detailing one method of manufacturing an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0013]      FIG. 3  shows an embodiment of the present invention.  FIG. 3   a  shows a U shape micro actuator comprising two moving arms  303  and a base part  301 . The base part  301  is partially potted to the point  320  of the suspension. A head slider  302  is coupled with the U-shape microactuator&#39;s moving arms  303  and support plate  8000  (refer to  FIGS. 3   c  and  3   d ) at their top ends  305  &amp;  306 . Two piezoelectric strips  304  are coupled with both of the moving arms  303  along the sides. The trailing edge of the head slider and the top ends of the moving arms are physically coupled with a moving plate  312 . A bonding plate  313  is physically coupled with the moving plate  312 . Four conductive balls (e.g., gold balls or solder balls)  307  electrically couple the head slider and head suspension to traces  309 . Three conductive balls  308  (gold or solder balls) on both sides of the U-shape microactuator electrically couple the microactuator and the head suspension to traces  310 .  FIG. 3   b  shows a cross section view of  FIG. 3   a .  FIG. 3   c  shows a detailed view of the apparatus without head  302 . Support plate  8000  is used to adjust the slider&#39;s height because the thickness of support plate  8000  provides for any required of adjustment of height of head slider  302 . The appropriate height of the slider is a height at which is able to at least read/write the data from/to a magnetic disk. Therefore, it is at least required to project the slider airbearing surface upward from the top surface of moving arms  303 . The top surface of bonding plate  312  is level with support plate  8000 , and the bonding plate  312  is flatly disposed side by side on the support plate  8000  and connects with the pad of the slider. The bonding plate  312  may also be inserted between the two top ends of the moving arms and sandwiched between the moving plate and the part of head slider.  FIG. 3   d  shows the base part  3010   f  the U-shape microactuator situated partially on the predetermined position of the suspension tongue  311 . The bonding plate includes traces  309  set on the moving plate to connect with the pad of head slider.  FIG. 3   e  shows a profile view of the current embodiment where the head slider sits partially on the position  320  of suspension tongue  311 . The suspension dimple  316  on a load beam  314  supports the suspension tongue. A parallel gap  315  exists between the suspension tongue and the bottom of the microactuator. This allows the microactuator to move smoothly, without interference, during voltage excitations. In this embodiment, support plate  8000  (the slider height adjuster) maintains the strength of micro-actuator by holding smaller sized sliders on the current microactuator even if the slider size is getting smaller.  
         [0014]      FIG. 4  shows another embodiment of this invention.  FIG. 4   a  shows a U-shape microactuator comprising a base part  401  and two moving arms  402 . The base part  401  of the microactuator is partially potted with the suspension tongue  406 . A head slider  404  is coupled with the moving arms at the top end  418  on both sides (see  FIG. 4   b ). Two piezoelectric strips  403  are coupled with the moving arms along the outside. The trailing edge of the head slider and the two moving arms of the microactuator are physically coupled with moving plate  409 . Four conductive balls  408  (gold ball bonding or solder bump bonding) electrically couple the head slider  404  and the head suspension to traces  413 . Three conductive balls  407  on both sides of the U-shape micro actuator electrically couple the microactuator and the head suspension to traces  414 .  FIG. 4   b  shows a cross section view. Bonding plate  410  is situated on the moving plate  409 . Each of the moving arm ends of the micro actuator  401  has a side step  419  as a slider height adjuster.  FIG. 4   c  shows the U-shape microactuator. In this embodiment, the side-step  419  on both ends of the arms  418  support the head slider. The height (thickness) of side-steps  419  operate to adjust the height of the head slider. This design allows smaller sized head sliders to be coupled to the current micro actuator and moving plate.  FIG. 4   d  provides an additional detailed view of this embodiment of the invention detailing the aforementioned components. In this embodiment, side steps  419  (the slider height adjuster) maintain the strength of micro-actuator by holding smaller sized sliders on the current micro-actuator even if the slider size is getting smaller.  
         [0015]      FIG. 5  shows another embodiment of the present invention.  FIG. 5   a  shows a metal microactuator frame  500  comprising two moving arms  503  and a base part  501 . The base part  501  is partially potted with a suspension tongue. A head slider  502  is coupled on the bottom side with support plate  504  that is further coupled to the moving arms  503 . A piezoelectric strip  514  (refer to  FIG. 5   b ) is coupled along the outside of each moving arm  503 . The bonding plate  505  is sandwiched between the top arm and head slider  502 . The slider&#39;s height is adjusted by the thickness of bonding plate  507 . Four conductive balls  507  (gold ball or solder ball) electrically couple the head slider  502  and the head suspension to traces  512 . Three conductive balls  506  on both sides of the microactuator electrically couple the microactuator and the head suspension to traces  513 .  FIG. 5   b  shows a detailed view the embodiment including the slider and the top arm. Using such a design allows smaller sized head sliders to be coupled to the current type of micro actuator.  FIG. 5   c  shows a detailed bottom side view of the head slider coupled with the top arm. In this embodiment, bonding plate  505  (the slider height adjuster) maintains the strength of micro-actuator by holding smaller sized sliders on the current micro-actuator even if the slider size is getting smaller.  
         [0016]      FIG. 6  shows another embodiment of the present invention with a metal microactuator frame  600  including a micro actuator comprising moving arms  603  and base part  601 . The base part  601  is partially potted to the suspension tongue. A head slider  602  is coupled on its bottom side with a bonding plate  605  that is further coupled to top arm  604 . The top arm  604  may be separated into two parts with each part having a forming step  615  (refer to  FIG. 6   c ). A piezoelectric strips  616  is coupled along the outside of both the moving arms. Four conductive balls  607  (gold ball or solder ball) electrically couple the head slider and the suspension to traces  612 . Three conductive balls  606  on both sides of the microactuator electrically couple the microactuator and the suspension to traces  613 .  FIG. 6   b  shows a side view of the head slider  602 , the forming step  615  and the bonding  605  plate.  FIG. 6   c  shows a bottom side view of the head slider  602 , the forming step  615  and the bonding plate  605 . In this embodiment, forming step  615  (the slider height adjuster) maintains the strength of microactuator by holding smaller sized sliders on the current microactuator even if the slider size is getting smaller. Using such a design allows smaller sized head sliders to be coupled to the current type of micro actuator.  
         [0017]      FIG. 7  shows another embodiment of the present invention. The microactuator includes two moving arms  703  and base part  701 . The base part is partially potted with a suspension tongue. Piezoelectric strip  715  is coupled along the outside of each the moving arms of the micro actuator. The trailing edge of the head slider and the top arm of the microactuator are physically coupled with the bonding plate  705 . Four conductive balls  707  (gold ball bonding or solder bump bonding) electrically couple the head slider and the suspension to traces  712 . Three conductive balls  706  on both sides of the micro actuator electrically couple the micro actuator and the head suspension to traces  713 .  FIG. 7   b  shows another view the head slider coupled with bonding plate  705 . The bonding plate has a forming step  716  in the position where the head slider rests allowing for the adjustment of the height of slider. The slider&#39;s height is adjusted by this height of forming step  716  disposed on the bonding plate  705 .  FIG. 7   c  shows an alternate view of the aforementioned microactuator and its peripheral. Using such a design allows smaller sized head sliders to be coupled to the same type of micro actuator. In this embodiment, forming step  716  (the slider height adjuster) maintains the strength of microactuator by holding smaller sized sliders on the current microactuator even if the slider size is getting smaller.  
         [0018]      FIG. 8  shows a flowchart of an embodiment of a method of manufacturing a microactuator device according to an embodiment of the present invention. Starting from step  801 , in step  802 , the support plate  8000  is inserted in miroactuator  8012 , and the slider  8011  is mounted to a top arm  8013  of the microactuator  8012  using an epoxy (not shown). In process  803 , UV light  8014  cures the epoxy to fix the bond between the slider and micro actuator top arm. In step  804 , the slider  8011  and micro actuator  8012  are partially mounted (potted) to the suspension  8015  using an epoxy (not shown). In step  805 , the UV light  8014  cures the epoxy in order to affix the base part of the micro actuator and the suspension. In process  806 , conductive balls  8016  are used to electrically connect the slider and suspension. Conductive balls  8017  are used to electrically couple the micro actuator and the suspension tongue. In step  807 , an oven heater  8018  is used to help sufficiently cure the epoxy to ensure that the slider  8011 , microactuator  8012  and suspension  8015  are sufficiently well-connected.