Abstract:
A test fixture for testing magnetic heads to be used in a magnetic data recording system. The test fixture includes a test fixture body that includes lead terminals. The lead terminals, which can be constructed of Si have a top surface and first and second laterally opposed sides. An electrically conductive material is formed over the lead terminal and extends down the sides of the lead terminal. Extending the lead terminal down the sides of the lead terminal as well as over the top surface provides improved adhesion of the electrically conductive lead material to the lead terminal. This improved adhesion is especially beneficial for use in such a test fixture, because the test fixture is designed to flex during use, which would otherwise contribute to de-lamination of the electrically conductive lead material from the lead terminal.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to magnetic data recording, and more particularly to a device for holding a slider during testing of magnetic recording elements. 
       BACKGROUND 
       [0002]    At the heart of a computer is an assembly that is referred to as a magnetic disk drive. The magnetic disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension arm adjacent to a surface of the rotating magnetic disk and an actuator that swings the suspension arm to place the read and write heads over selected tracks on the rotating disk. The read and write heads are directly located on a slider that has an air bearing surface (ABS). The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating, but when the disk rotates air is swirled by the rotating disk. When the slider rides on the air bearing, the write and read heads are employed for writing magnetic impressions to and reading magnetic impressions from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions. 
         [0003]    The write head includes at least one coil, a write pole and one or more return poles. When current flows through the coil, a resulting magnetic field causes a magnetic flux to flow through the coil, which results in a magnetic write field emitting from the tip of the write pole. This magnetic field is sufficiently strong that it locally magnetizes a portion of the adjacent magnetic media, thereby recording a bit of data. The write field then, travels through a magnetically soft under-layer of the magnetic medium to return to the return pole of the write head. 
         [0004]    A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor, a Tunnel Junction Magnetoresistive (TMR) sensor or a scissor type magnetoresistive sensor can be employed to read a magnetic signal from the magnetic media. The magnetoresistive sensor has an electrical resistance that changes in response to an external magnetic field. This change in electrical resistance can be detected by processing circuitry in order to read magnetic data from the magnetic media. 
         [0005]    Prior to assembly into the data recording system, the magnetic read sensor and magnetic write head formed on the slider can be tested to ensure that the their performance is within acceptable standards. Once their performance has been found to be within desired tolerance ranges, the slider and associated read/and write heads can be permanently installed into the data recording system by mounting the slider onto the suspension. 
       SUMMARY 
       [0006]    The present invention provides a test fixture that includes at least one lead terminal having first and second laterally opposed sides and a top surface. An electrically conductive lead material is formed over the top surface of the lead terminal and also extends down the sides of the lead terminal. 
         [0007]    Extending the electrically conductive lead material down the sides of the lead terminal advantageously improves adhesion of the electrically conductive lead material to the lead terminal. This is especially advantageous, because the test fixture is designed to flex during use. This flexing of the test fixture would otherwise cause de-lamination of the electrically conductive lead material. However, forming the electrically conductive lead material so that it extends down the sides of the lead terminal prevents such de-lamination, thereby increasing the life and reliability of the test fixture. 
         [0008]    These and other features and advantages of the invention will be apparent upon reading of the following detailed description of the embodiments taken in conjunction with the figures in which like reference numeral indicate like elements throughout. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    For a fuller understanding of the nature and advantages of this invention, as well as the preferred mode of use, reference should be made to the following detailed description read in conjunction with the accompanying drawings which are not to scale. 
           [0010]      FIG. 1  is a schematic illustration of a disk drive system in which the invention might be embodied; 
           [0011]      FIG. 2  is an exploded view of a slider and suspension assembly for use in a magnetic data recording system; 
           [0012]      FIG. 3  is a perspective view of a test fixture for holding a slider during testing of a magnetic read/write head formed thereon; 
           [0013]      FIG. 4  is an exploded view of a slider, test fixture and suspension assembly; 
           [0014]      FIG. 5 a    is a top down view of an etched blank of a test fixture and lead lines formed thereon; 
           [0015]      FIG. 5 b    is an enlarged view of a portion of the etched bland of a text fixture of  FIG. 5   a;    
           [0016]      FIG. 6  is a cross-sectional view of a portion of a text fixture as seen from line  6 - 6  of  FIG. 5   b;    
           [0017]      FIGS. 7-13  are cross sectional views of a portion of a test fixture in various intermediate stages of manufacture in order to illustrate a method of manufacturing a magnetic test fixture; and 
           [0018]      FIG. 14  is a cross sectional view of portions of a test fixture illustrating opposite ends of a lead structure formed thereon. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    The following description is of the best embodiments presently contemplated for carrying out this invention. This description is made for the purpose of illustrating the general principles of this invention and is not meant to limit the inventive concepts claimed herein. 
         [0020]    Referring now to  FIG. 1 , there is shown a disk drive  100 . The disk drive  100  includes a housing  101 . At least one rotatable magnetic disk  112  is supported on a spindle  114  and rotated by a disk drive motor  118 . The magnetic recording on each disk may be in the form of annular patterns of concentric data tracks (not shown) on the magnetic disk  112 . 
         [0021]    At least one slider  113  is positioned near the magnetic disk  112 , each slider  113  supporting one or more magnetic head assemblies  121 . As the magnetic disk rotates, slider  113  moves in and out over the disk surface  122  so that the magnetic head assembly  121  can access different tracks of the magnetic disk where desired data are written. Each slider  113  is attached to an actuator arm  119  by way of a suspension  115 . The suspension  115  provides a slight spring force which biases the slider  113  against the disk surface  122 . Each actuator arm  119  is attached to an actuator means  127 . The actuator means  127  as shown in  FIG. 1  may be a voice coil motor (VCM). The VCM comprises a coil movable within a fixed magnetic field, the direction and speed of the coil movements being controlled by the motor current signals supplied by the controller  129 . 
         [0022]    During operation of the disk storage system, the rotation of the magnetic disk  112  generates an air bearing between the slider  113  and the disk surface  122 , which exerts an upward force or lift on the slider. The air bearing thus counter-balances the slight spring force of the suspension  115  and supports the slider  113  off and slightly above the disk surface by a small, substantially constant spacing during normal operation. 
         [0023]    The various components of the disk storage system are controlled in operation by control signals generated by control unit  129 , such as access control signals and internal clock signals. Typically, the control unit  129  comprises logic control circuits, and a microprocessor. The control unit  129  generates control signals to control various system operations such as drive motor control signals on line  123  and head position and seek control signals on line  128 . The control signals on line  128  provide the desired current profiles to optimally move and position the slider  113  to the desired data track on the media  112 . Write and read signals are communicated to and from write and read heads  121  by way of recording channel  125 . 
         [0024]      FIG. 2  shows an exploded view of a slider assembly  113  and a portion of a suspension assembly  115 . During manufacture, the slider  113  is mounted to the suspension assembly as indicated by arrow  202 . The slider  113  has a magnetic read/write head  121  formed at a trailing edge of the slider  113 , and the read/write head  121  is electrically connected with contact pads  204  by electrically conductive lead lines that are not shown in  FIG. 2 . 
         [0025]    Once the slider  113  is permanently mounted to the suspension assembly  115 , the contact pads  204  electrically connect with lead lines  206  formed on the suspension assembly  115 , whereby the read/write head  121  can electrically communicate with processing circuitry  129 ,  125  ( FIG. 1 ). Once the slider  113  has been permanently mounted onto the suspension  115 , it cannot be easily removed. Therefore, it is desirable to test the performance of the read/write head  121  prior to permanently mounting the slider  113  to the suspension assembly  115 . Should the read/write head  121  not fall within desired performance parameters, then the slider  113  can be scrapped and replaced with another slider  113  and read/write head  121 . 
         [0026]      FIG. 3  shows a perspective view of test fixture  302 , and  FIG. 4  is an exploded view of the test fixture  302  suspension  115 , and slider  113 . As seen in  FIG. 4 , the test fixture  302  is configured to receive the slider  113  and to temporarily mount within the suspension assembly  115 . As seen more clearly in  FIG. 3 , the test fixture  302  has a guide channel  304  for receiving the slider  113 . The test fixture  302  also has springs  306  and an engagement tab  308 . To load a slider  113  into the test fixture  302 , the engagement tab  308  can be pulled outward and the slider  113  inserted into the guide channel  304 . When the engagement tab  308  is released, the springs  306  will bias the engagement tab  308  toward the slider, securely holding the slider  113  in place. 
         [0027]    The test fixture  302  also has slider side electrically conductive contact pads  310  that are electrically connected with suspension side electrically conductive contact pads  314  by electrically conductive lead lines  312 . These will be described in greater detail herein below. When the slider  113  is held within the test fixture  302 , the contact pads  204  of the slider  113  ( FIG. 2 ) will engage the contact pads  310  of the test fixture  302 . Similarly, when the test fixture  302  is temporarily mounted on the suspension assembly  115  as shown in  FIG. 4 , the suspension side contact pads  314  will engage contact pads  402  of the suspension assembly  115 . This, therefore, allows the contact pads  204  of the slider  113  to be temporarily electrically connected with the lead lines  206 , thereby allowing the performance of the magnetic read/write heads  121  to be tested prior to final, permanent mounting of the slider  113  to the suspension assembly  115 . 
         [0028]      FIG. 5 a    shows a top down view of the test fixture  302  including a test fixture body portion  505 , lead lines  312 , slider side contact pads  310  and suspension assembly side lead pads  314 .  FIG. 5 b    is an enlarged view of the area shown in box  502  of  FIG. 5 a   . As can be seen,  FIG. 5 b    shows a portion of two lead lines  312 . 
         [0029]      FIG. 6  shows a cross sectional view of a portion of the test fixture  302  with lead lines  312  as seen from line  6 - 6  of  FIG. 5 b   .  FIG. 6  shows the test fixture body portion  505  and an electrically conductive lead portion  312 . The lead portion  312  includes a lead terminal portion  504  with an electrically conductive lead material  506  formed there-over. A seed layer  508  may also be provided beneath the electrically conductive lead material  506 . The test fixture body  505  and lead terminal  504  can be formed of a material such as Si, which allows it to be sufficiently flexible and also sufficiently stiff to effectively hold the slider  113  ( FIG. 4 ) therein. The electrically conductive material  506  can be constructed of a material such as Au, which has good electrical conductivity, ductility and corrosion resistance. The seed layer  508  can be an electrically conductive material that can be deposited by a process such as sputter deposition. 
         [0030]    As can be seen in  FIG. 6 , the electrically conductive lead material  506  (and seed layer  508 ) wrap around the sides of the terminal structure  504 , rather than only being on the top of the terminal structure  504 . While this wrapping around of the lead material  506  requires some additional manufacturing complexity and would not, therefore, be an obvious design choice, this structure provides great benefit with regard to function and reliability of the test fixture  302 . As those skilled in the art will appreciate, operation of the test fixture  302  requires a great deal of flexure of the structure  504  underlying the lead material  506 . Further, the test fixture  302  is designed to be used tens of thousands of times. Therefore, the structure is preferably very durable. If the electrically conductive lead material  506  were only plated at the top of the underlying terminal structure  504  it would be prone to de-lamination and would have insufficient robustness and reliability. Wrapping the lead material  506  around the terminal structure  504  so that it is applied to the sides of the terminal  504  as well as the top greatly improves adhesion, thereby ensuring that the test fixture will last through many needed test cycles. Further, the wrap around structure of the lead layer  506  improves electrical conduction by increasing the amount of electrically conductive material. Preferably, the electrically conductive lead material  506  and seed layer  508  extend ⅓ to ⅔ of the way down the sides of the lead terminal structure  504 , or about half way down the sides of the lead terminal structure  504 . 
         [0031]      FIGS. 7-13  show a test fixture in various intermediate stages of manufacture in order to illustrate a method of manufacturing a test fixture with wrap-around lead material such as described above. With particular reference to  FIG. 7 , a substrate  702  is formed. This substrate  702  can be a material such as Si which will be later etched away, as will be seen. An etch stop layer  704  is deposited over the substrate  702 . The etch stop layer  704  can be a material such as SiO 2  that is resistant to removal by reactive ion etching. Then, a layer of material  706  that will make up the body of the test fixture  302  ( FIG. 5 a   ) is deposited over the etch stop layer  704 . The text fixture material  706  can be a material such as Si. A mask structure  708  is then formed over the test fixture material  706 . The mask is patterned with openings that are configured to define the shape of a test fixture, such as that shown in  FIG. 5   a.    
         [0032]    After the mask  708  has been formed, a reactive ion etching (RIE) can be performed to remove portions of the test fixture material  706  that are not protected by the mask  708 , thereby leaving a structure as shown in cross-section in  FIG. 8 . The mask  708  can be removed by a suitable mask liftoff process such as chemical liftoff. Again, this etching process etches the test fixture material  706  into a shape such as that shown in top-down view in  FIG. 5 a    and leaves a lead terminal portion  706   a  ( FIG. 8 ) in a region where an electrically conductive lead is to be formed. The reactive ion etching terminates at the etch stop layer. In addition to reactive ion etching, other suitable material removal processes could be used to remove the exposed portions of the layer  706 . 
         [0033]    With reference now to  FIG. 9 , an electrically conductive seed layer  902  is deposited, such as by sputter deposition. This layer  902  will provide an electroplating seed layer. Then, with reference to  FIG. 10 , a layer of photoresist material  1002  is deposited. The photoresist  1002  is exposed and developed so as to recess the photoresist only in the region of the lead terminal  706   a , as shown in  FIG. 11 . The exposure and development of the photoresist can be controlled so as to recess the photoresist  1002  and expose the lead terminal portion  706   a  to a desired degree only in the region of the lead terminal  706   a . Preferably, the thickness of the photoresist  1002  is reduced down to about one half of the thickness of the lead terminal portion  706   a  as shown in  FIG. 11  or from ⅓ to ⅔ the thickness of the lead terminal portion  706   a  as measured in a vertical direction in  FIG. 11 . 
         [0034]    Then, with reference to  FIG. 12 , a layer of electrically conductive lead material  1202  is electroplated onto the seed layer  902  over the lead terminal portion  706   a . As shown, the lead material  1202  will only be electroplated in regions where the seed layer  902  is exposed. The lead material  1202  can be a material having good electrical conductivity and good corrosion resistance. The lead material  1202  is preferably Au. After the lead material  1202  has been electroplated, the photoresist material  1002  and the seed layer material  902  can be removed by a process such as a chemical removal process, thereby leaving a structure as shown in  FIG. 13 . As can be seen in  FIG. 13 , the lead material  1202  wraps around the sides of the lead terminal portion  706   a  as desired and is only formed in the region of the lead terminal portion  706   a . After the above processes have been performed, the underlying substrate  702  and etch stop layer  704  can be removed, leaving the fixture body  706  free standing. 
         [0035]      FIG. 14  shows a cross sectional view of a lead structure  312  showing opposite ends of the lead structure  312 . In  FIG. 13 , a first end is a slider end contact  1302  that is designed to make contact with a lead pad  204  of a slider  113  ( FIG. 2 ). The opposite end is a suspension side contact  1304  that is configured to make electrical contact with a suspension  115  ( FIG. 2 ). The lead material  506  extends down an end surface  1402  at the slider end contact side  1302 , and also extends down an end surface  1404  at the suspension contact side  1304 . As can be seen in  FIG. 13 , the electrical lead material  506  extends further down the end surface  1304  than it does down the end surface  1306 . Preferably, the lead material  506  extends about one half of the way down the end surface  1402  and about ⅔ down the end surface  1404 . This difference can be accomplished by changing the exposure and development conditions performed on the photoresist in the process described above with reference to  FIG. 11 . 
         [0036]    While various embodiments have been described above, it should be understood that they have been presented by way of example only and not limitation. Other embodiments falling within the scope of the invention may also become apparent to those skilled in the art. Thus, the breadth and scope of the inventions should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.