Abstract:
In accordance with one embodiment, an apparatus is disclosed that comprises a submount operable to integrate with a laser as a laser submount assembly; a predetermined portion of the submount configured to bond with the laser; a bonding pad positioned on the predetermined portion of the submount for integrating the laser with the submount.

Description:
BACKGROUND 
       [0001]    Magnetic media storage devices have relatively recently begun to use heat assisted magnetic recording (also known as HAMR). One implementation of heat assisted magnetic recording is to use a laser, such as a laser diode, affixed to an assembly that is positioned on a slider. The laser is used to heat a targeted portion of the magnetic medium, such as a disk. Due to the small scale of the devices used, proper alignment of the laser relative to the slider can be an issue. 
       SUMMARY 
       [0002]    In accordance with one embodiment, an apparatus is disclosed that includes a submount operable to integrate with a laser as a laser submount assembly; a predetermined portion of the submount configured to bond with the laser; and a bonding pad positioned on the predetermined portion of the submount for integrating the laser with the submount. 
         [0003]    In accordance with another embodiment, an apparatus is disclosed that includes a slider comprising an air bearing surface and a waveguide surface; and a mechanical stop configured to align a submount in a predetermined position. 
         [0004]    In yet another embodiment, a method is disclosed that includes forming a mechanical stop on a slider in a predetermined position, wherein the predetermined position is operative to align a submount on the slider. 
         [0005]    Further embodiments will be apparent to those of ordinary skill in the art from a consideration of the following description taken in conjunction with the accompanying drawings, wherein certain methods, apparatuses, and articles of manufacture are illustrated. This summary is provided merely to introduce certain concepts rather than to identify any key or essential features of the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    A further understanding of the nature and advantages of the present technology may be realized by reference to the figures, which are described in the remaining portion of the specification. 
           [0007]      FIG. 1  illustrates an example of a disc drive in which a submount assembly may be utilized, in accordance with one embodiment. 
           [0008]      FIG. 2  illustrates an example of a laser submount assembly integrated on a slider, in accordance with one embodiment. 
           [0009]      FIG. 3  illustrates an example of a submount that is configured with a portion for coupling with a laser, in accordance with one embodiment. 
           [0010]      FIG. 4  illustrates an example of a submount bonded with a laser as a laser submount assembly, in accordance with another embodiment. 
           [0011]      FIG. 5  illustrates an example of a slider with a portion of the slider configured to receive a submount, in accordance with one embodiment. 
           [0012]      FIG. 6  illustrates an example of a laser submount assembly integrated with a slider, in accordance with one embodiment. 
           [0013]      FIG. 7  illustrates a flow chart that illustrates a method of configuring a slider, in accordance with one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Embodiments of the present technology are disclosed herein in the context of a disc drive system. However, it should be understood that the technology is not limited to a disc drive system and could readily be applied to other technology systems as well. 
         [0015]    With reference now to  FIG. 1 , an example of a disc drive system in accordance with one embodiment is shown. A disc drive system is but one example where disclosed technology may be utilized.  FIG. 1  illustrates a perspective view  100  of an example transducer head using heat assisted magnetic recording. A disc  102  rotates about a spindle center or a disc axis of rotation  104  during operation. The disc  102  includes an inner diameter  106  and an outer diameter  108  between which are a number of concentric data tracks  110 , illustrated by circular lines. It should be understood, however, that the described technology may be employed with other types of storage media, including patterned magnetic media, discrete track (DT) media, etc. 
         [0016]    Information may be written to and read from recorded magnetic domains on the disc  102  in different data tracks  110 . A transducer head  124  is shown mounted on an actuator assembly  120  at an end distal to an actuator axis of rotation  122 . The transducer head  124  flies in close proximity above the surface of the disc  102  during disc operation. The actuator assembly  120  rotates during a seek operation about the actuator axis of rotation  122  positioned adjacent to the disc  102 . The seek operation positions the transducer head  124  over a target data track of the data tracks  110 . 
         [0017]    The exploded view  140  shows slider  120  attached to a laser submount assembly  134  having a laser light source  130  (e.g., a laser diode) or other light source (e.g., a light emitting diode (LED)). The laser submount assembly  134  is integrated with the slider  120 . In one implementation, the integration can be accomplished utilizing a bonding pad and/or bonding cavity (designated by the dashed lines), as discussed in more detail below. Other types of coupling may be utilized as well. 
         [0018]    The slider  120  can include a writer section (not shown) having a main write pole magnetically coupled to a return or opposing pole by a yoke or pedestal. A magnetization coil surrounds the yoke or pedestal to induce magnetic write pulses in the write pole. In other implementations, the slider  120  may be constructed without a yoke or return pole. The slider  120  may also include one or more read sensors (not shown) for reading data off of the media. 
         [0019]    Light from the laser light source  130  is shown directed through a waveguide  132  on the trailing edge of the slider  120 . Using the waveguide, the light can then be redirected and/or focused on a point on the media in close proximity to the write pole on the slider  120 . A near-field transducer (NFT) may also be mounted on the slider  120  to further concentrate the light on the point on the media  108 . In another implementation, one or more of the laser light source  130 , waveguide  132 , mirrors (not shown), and/or NFTs (not shown) are mounted on an area of the slider  120  other than the trailing surface. 
         [0020]    By using a laser coupled with the write head, a heat-assisted magnetic recording (HAMR) recording technique can be utilized. A HAMR system allows the light from the laser to heat a portion of the magnetic recording media prior to a write operation being performed. The light from the laser can be focused via a waveguide on a precise location of the magnetic media prior to the write head performing a write operation. This allows improved areal density to be achieved. A HAMR head thus allows the laser to be situated precisely so that the laser can be directed at the desired location on the magnetic recording media. One way of mounting the laser on the write head is to utilize a submount device. This allows the laser to be mounted on the slider. A laser diode can be utilized as the laser in accordance with one embodiment. 
         [0021]    Referring now to  FIG. 2 , an example of a laser-on-slider can be seen. A laser submount  204  is shown integrated with a laser diode  208 . A submount can serve as a mounting piece for the laser with respect to the slider. For example, it can be utilized to mount a laser to a slider without requiring the laser to actually touch the slider. The laser diode  208  is positioned over a waveguide  216  that is disposed within a slider  212 . By choosing material with good thermal conductivity for the submount, the submount can also serve to remove heat from the laser during operation 
         [0022]      FIG. 3  illustrates an example of a submount that facilitates proper alignment of a laser.  FIG. 3  shows a submount  304  that includes a bonding pad  308 . The bonding pad can be configured in a predetermined position to facilitate integration of a laser diode to the submount. The bonding pad can be configured in the shape of the laser. One type of bonding that can be utilized is soldering. Similarly, under bump metallization may be used for the bonding pad to establish an electrical coupling with the laser diode. While  FIG. 3  shows a continuous bonding pad, multiple bonding pads could alternatively be used. When multiple small pads are utilized, self alignment can be achieved via reflow. 
         [0023]    The bonding area can be placed in a predetermined portion on the submount so that when the laser is attached at the bonding position, the laser will be in proper alignment with the waveguide during operation. 
         [0024]      FIG. 3  also shows surface interconnect pads  312  and  314 . Surface interconnect pads may be used to provide an electrical path to the laser electrode. The pads can be used as interconnect and/or probing pads. In which case, the pads can electrically connect to the laser electrodes, suspension pads, or head trailing edge pads. For example, direct wiring, wire bonding, or solder bonding can be utilized to make these further connections to the pads. 
         [0025]      FIG. 3  also shows machine vision alignment features  316  indicated by “+” signs. The alignment features can be, for example, visual fiducials or targets. The alignment features can be particularly helpful if the placement of the laser on the submount needs directed/assisted alignment in order to achieve critical alignment with the waveguide. Another example of an alignment feature is the edge of the submount itself. The edge of the submount may directly serve as such an alignment feature. Meanwhile, other features for alignment can also be included in the laser to assist the critical alignment 
         [0026]    In accordance with another embodiment, mechanical stops can be utilized for the alignment features. This can be particularly useful when self alignment is utilized to pull/drive the laser against the mechanical stops of the submount. 
         [0027]    The submount itself may also utilize a bonding pad. For example an under bump metallization pad may be located on the bottom of the submount. This under bump metallization pad may be utilized to mount the submount to the slider mechanically and electrically. 
         [0028]    Referring now to  FIG. 4 , a side view of a submount assembly can be seen. The submount  404  is shown integrated with a laser diode  413 . A soldering pad  408  is shown as the connecting mechanism between the laser and the submount. Angle “α” (alpha) is shown as the angle between the edge of the laser and the bottom of the submount. In one embodiment, an angle of 90° is preferred so that the laser directs light at the waveguide when the bottom of the submount is positioned parallel to the waveguide surface of the slider. A space  417  is shown between the bottom of the laser edge and the bottom of the submount. This can also be referred to as the laser-facet-to-submount edge. This space allows the submount to be oriented in a depression in the slider in one embodiment. The space can be a predetermined distance in order to accommodate predetermined specifications.  FIG. 4  also shows an under bump metallization pad  415 . 
         [0029]    Referring now to  FIG. 5 , a slider  512  having a recessed cavity is shown. The recessed cavity can be configured to receive a laser submount assembly such as that shown in  FIG. 4 . The cavity  515  can receive a portion of the laser submount assembly. A plateau  519  for the waveguide is also shown as part of slider  512 . Thus, when the laser submount assembly is positioned on the slider, the bottom of the laser submount assembly is disposed in cavity  515  and the laser facet edge is in juxtaposition with plateau  519 . Plateau  519  can serve as the interface with a waveguide that is positioned in slider  512 . 
         [0030]    Referring now to  FIG. 6 , a submount assembly is shown integrated with a slider. Submount assembly  604  is shown having a laser  608 . The submount is disposed in a cavity where it can be coupled with the slider  612  by bonding materials. The offset of the bottom of the laser from the bottom of the submount allows the laser to be positioned above the waveguide. For example,  FIG. 6  shows the laser  608  positioned above the plateau for the waveguide. The dashed line shows the waveguide surface whereas the solid line shows the top of the cavity surface. 
         [0031]    The integration of the laser submount assembly with the slider allows the path of the light emitted from the laser to be precisely aligned with the waveguide. The alignment mechanism could involve active alignment with the laser activated. Alignment could involve real-time signals (electronic, optical, etc.) for feedback through either an internal sensor built in the laser, submount, slider, or an external sensor. Alternatively, passive alignment without a real time feedback mechanism could be utilized. Passive alignment is generally preferred for higher process throughput and inherently reduced complexity. One approach to achieve passive alignment is to fabricate mechanical stops at designated locations on the slider. The cavity in  FIGS. 5 and 6  is one example of such a mechanical stop. The cavity allows passive alignment of the laser submount assembly along the Z-direction. The laser submount assembly is oriented substantially perpendicular to the waveguide surface of the slider. Of course other designs are possible. And in accordance with some embodiments one may choose to utilize a non-perpendicular angle. 
         [0032]    The examples shown in  FIG. 5  and in  FIG. 6  shows the cavity recessed into the back of the slider opposite to the air bearing side of the slider. The cavity has one or both of X and Y dimensions smaller than that of the submount assembly so as to form mechanical stop along Z direction. The depth of the cavity can accommodate bonding materials, such as adhesive or solder. When the laser submount assembly is mounted to the slider, the alignment of the laser with the waveguide is passive if the laser submount assembly is pushed against and stops at the surface defined by the cavity top, for example. The force pushing the laser submount assembly can be any mechanical or external applied force combined with the adhesion force generated by bonding materials pre-disposed in the cavity. The mechanical stops along X or Y direction can be similarly fabricated. 
         [0033]    If the laser emitting facet to submount edge spacing extends beyond the allowed spacing for laser emitting point to waveguide surface, a waveguide plateau may be fabricated by milling down other areas on the slider back. The step height of the waveguide surface to the cavity top can be configured to be sufficient to position the laser facet into a predetermined proximity with the waveguide surface. 
         [0034]    Referring now to  FIG. 7 , a flowchart  700  is shown which illustrates a method of forming a slider in accordance with one embodiment. In operation block  702 , a plateau is formed on the waveguide surface of the slider. In operation block  704 , one can form a mechanical stop on a slider in a predetermined position. For example, a cavity can be formed in the slider to receive a portion of a submount. One manner of forming the cavity is to mill the surface of the slider that is opposite the air bearing surface. 
         [0035]    One can utilize bonding materials to bond the submount assembly with the slider. This can be accomplished by disposing bonding materials in the cavity or on the submount assembly or both. Operation block  706  shows that bonding materials are disposed in the cavity in accordance with one example. The mechanical stop may also be configured in a position that allows the laser mounted on the submount to align with the waveguide disposed in the slider. This is shown by operation block  708 . For example, a laser mounted on the submount may be aligned by active of passive alignment with the waveguide disposed in the slider. 
         [0036]    It is noted that many of the structures, materials, and acts recited herein can be recited as means for performing a function or step for performing a function. Therefore, it should be understood that such language is entitled to cover all such structures, materials, or acts disclosed within this specification and their equivalents, including any matter incorporated by reference. 
         [0037]    It is thought that the apparatuses and methods of embodiments described herein will be understood from this specification. While the above description is a complete description of specific embodiments, the above description should not be taken as limiting the scope of the patent as defined by the claims.