Vertical cavity surface emitting laser and head gimbal assembly and fabrication process

Abstract

The embodiments of the present disclosure generally relate to vertical cavity surface emitting lasers (VCSELs), head gimbal assemblies for mounting VCSELs, devices incorporating such articles, and processes for forming VCSELs. In one embodiment, a VCSEL device is provided. The VCSEL device includes a chip for mounting to a slider, the chip having a plurality of surfaces and a notch, the plurality of surfaces including a bottom surface facing the slider, a top surface opposite the bottom surface, and a plurality of side surfaces, the notch forming a concave edge spaced from the bottom surface and toward the top surface, the notch having a shoulder, a side, and an angle (θ1) between the shoulder and the side. The VCSEL device further includes two laser diode electrodes positioned in any combination on one or more of the surfaces of the chip.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 211,288, filed June 16, 2021, and U.S. Provisional Application No. 63 / 211,302, filed June 16, 2021, each of which is incorporated by reference herein in their entirety.

[0002] FIELD OF THEINVENTION Embodiments of the present disclosure generally relate to vertical cavity surface emitting lasers, head gimbal assemblies for mounting vertical cavity surface emitting lasers, devices incorporating such articles, and processes for forming vertical cavity surface emitting lasers. [Background technology]

[0003] 2. Description of Related Art Heat-assisted magnetic recording (HAMR) is a type of energy-assisted recording technology that improves the recording density of magnetic recording media. In HAMR, a laser source is located next to or near a writing element to generate heat, such as a laser source that excites a near-field transducer (NFT) to generate heat at the writing location of the magnetic recording medium. One approach to providing heat for HAMR involves using a vertical cavity surface emitting laser (VCSEL) to direct laser light through a magnetic recording head to the magnetic media. Here, the VCSEL is attached to the top surface of the slider, and one or more laser beams are emitted from the bottom surface of the VCSEL and directed into a corresponding number of waveguide structures in the HAMR head. The waveguide structures feed into a multimode interference (MMI) device, which then directs the laser into the waveguides to focus on the near-field transducers (NFTs).

[0004] Although conventional VCSELs offer reduced cost and no mode hopping compared to other lasers, such as edge-emitting laser diodes, conventional VCSELs do not allow for active alignment to maximize coupling between the waveguide and the laser. This lack of active alignment is a result of the VCSEL's laser diode electrodes being connected to or facing the top surface of the slider. Furthermore, because the VCSEL's laser diode electrodes are connected to the slider, a complex backside patterning process is typically employed during slider fabrication.

[0005] What is needed are new and improved VCSELs, head gimbal assemblies (HGAs) for mounting VCSELs, and devices incorporating such components. Summary of the Invention

[0006] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to vertical cavity surface emitting lasers (VCSELs), head gimbal assemblies for mounting VCSELs, devices incorporating such articles, and processes for forming VCSELs.

[0007] In one embodiment, a vertical cavity surface emitting laser (VCSEL) device is provided. The VCSEL device includes a chip for mounting to a slider, the chip having a plurality of surfaces and a notch, the plurality of surfaces including a bottom surface of the chip facing the slider, a top surface of the chip opposite the top surface, and a plurality of side surfaces, the notch forming a concave edge spaced apart from the bottom surface toward the top surface, the notch having a shoulder, a side, and an angle (θ1) between the shoulder and the side. The VCSEL device further includes two laser diode electrodes positioned in any combination on one or more of the surfaces of the chip.

[0008] In one embodiment, a VCSEL device is provided, the VCSEL device comprising a chip for mounting to a slider, the chip having a plurality of surfaces, the plurality of surfaces including a bottom surface of the chip facing the slider, a top surface of the chip opposite the bottom surface, and a plurality of side surfaces, a first of the plurality of side surfaces being inclined at an angle (θ3) from a line (α) normal to the bottom surface. The VCSEL device further comprises two laser diode electrodes positioned in any combination on one or more of the plurality of surfaces of the chip.

[0009] In another embodiment, a head gimbal assembly is provided, the head gimbal assembly including a suspension, a slider attached to the suspension, and a VCSEL device attached to the slider. The VCSEL device of the head gimbal assembly includes a chip for mounting to the slider, the chip having a plurality of surfaces and a notch, the plurality of surfaces including a bottom surface of the chip facing the slider, a top surface of the chip opposite the top surface, and a plurality of side surfaces, and two laser diode electrodes positioned in any combination on one or more of the plurality of surfaces of the chip, the notch forming a concave edge spaced from the bottom surface and toward the top surface, the notch having a shoulder, a side, and an angle (θ1) between the shoulder and the side.

[0010] In another embodiment, a head gimbal assembly is provided, comprising: a VCSEL device, a chip for mounting to a slider, the chip having a plurality of surfaces, the plurality of surfaces including a bottom surface of the chip facing the slider, a top surface of the chip opposite the bottom surface, and a plurality of side surfaces, a first of the plurality of side surfaces being inclined at an angle (θ3) from a line (α) perpendicular to the bottom surface; and two laser diode electrodes positioned in any combination on one or more of the plurality of surfaces of the chip. The head gimbal assembly further includes a metal pad coupled to the top surface of the chip. [Brief description of the drawings]

[0011] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure briefly summarized above can be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure and therefore should not be considered as limiting its scope, as the present disclosure may admit of other equally effective embodiments. [Figure 1] 1 is a schematic illustration of an example magnetic media drive including a HAMR magnetic write head in accordance with at least one embodiment of the present disclosure. [Diagram 2] 1 is a schematic illustration of an embodiment of a portion of a cross-sectional side view of an example HAMR write head facing a magnetic disk, in accordance with at least one embodiment of the present disclosure. [Figure 3A] 1 illustrates a surface of a VCSEL that does not include laser diode electrodes, in accordance with at least one embodiment of the present disclosure. [Figure 3B] 1 illustrates a side view of an example VCSEL having a laser diode electrode coupled thereto, in accordance with at least one embodiment of the present disclosure. [Figure 3C] FIG. 2 illustrates a bottom view of an exemplary VCSEL with laser diode electrodes extending to the bottom surface, in accordance with at least one embodiment of the present disclosure. [Figure 4A] 1 is a schematic illustration of a cross-sectional view (down-track direction) of an example slider having an example VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 4B] FIG. 4B is a cross-sectional view (cross-track direction) of the example VCSEL shown in FIG. 4A in accordance with at least one embodiment of the present disclosure. [Diagram 5] FIG. 1 is a perspective view of a portion of an exemplary thermally assisted magnetic recording head gimbal assembly in accordance with at least one embodiment of the present disclosure. [Figure 6A]1 is a schematic illustration of a perspective view of an example slider having an example VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 6B] FIG. 6B is a bottom view of the example VCSEL shown in FIG. 6A in accordance with at least one embodiment of the present disclosure. [Figure 6C] FIG. 2 is a perspective view of an example VCSEL having laser diode electrodes disposed within a single trench having a width less than the width of the VCSEL, in accordance with at least one embodiment of the present disclosure. [Figure 6D] FIG. 1 is a perspective view of an example VCSEL with laser diode electrodes disposed within a single trench substantially the same size as the width of the VCSEL, in accordance with at least one embodiment of the present disclosure. [Figure 7A] FIG. 1 is a perspective view of an example VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 7B] FIG. 7B is a bottom view of the example VCSEL shown in FIG. 7A, in accordance with at least one embodiment of the present disclosure. [Figure 8A] 1 is a schematic illustration of a cross-sectional view of an example slider having an example VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 8B] FIG. 1 is a perspective view of an example VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 8C] FIG. 8C is a bottom view of the example VCSEL shown in FIG. 8B, in accordance with at least one embodiment of the present disclosure. [Figure 9A] FIG. 2 is a schematic illustration of a cross-sectional view of a slider having a VCSEL mounted thereon. [Figure 9B] 1 is a simplified illustration of a cross-sectional view (cross-track direction) of a slider with a VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 9C] FIG. 9C is a schematic illustration of a perspective view of the example VCSEL shown in FIG. 9B, in accordance with at least one embodiment of the present disclosure. [Figure 9D] 1 is a simplified illustration of a cross-sectional view (cross-track direction) of a slider with a VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 9E] 1 is a simplified illustration of a cross-sectional view (cross-track direction) of a slider with a VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 9F] 1 is a simplified illustration of a cross-sectional view (cross-track direction) of a slider with a VCSEL mounted thereon in accordance with at least one embodiment of the present disclosure. [Figure 10A] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 10B] 4 is a flowchart illustrating selected operations of an exemplary process for forming electrodes on a side surface of a VCSEL, in accordance with at least one embodiment of the present disclosure. [Figure 11] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 12] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 13] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 14] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 15] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 16] FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 17]FIG. 2 is a process flow diagram illustrating selected operations of an exemplary process for forming electrodes on side surfaces of a VCSEL in accordance with at least one embodiment of the present disclosure. [Figure 18A] 1 is a portion of a wafer illustrating variable angles of sidewalls formed during processing in accordance with at least one embodiment of the present disclosure. [Figure 18B] 18B illustrates the location of the angled sidewall from FIG. 18A in the formed VCSEL after processing, in accordance with at least one embodiment of the present disclosure. [Figure 19] 1 illustrates process variations for etching trenches on different sides of a VCSEL in accordance with at least one embodiment of the present disclosure.

[0012] To facilitate understanding, the same reference numbers have been used, whenever possible, to designate identical elements common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific mention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Embodiments of the present disclosure relate generally to vertical cavity surface emitting lasers (VCSELs), head gimbal assemblies for mounting VCSELs, and devices incorporating such articles, e.g., magnetic media drives. Processes for fabricating the VCSELs described herein are also described.

[0014] The inventors have discovered a new and improved VCSEL that allows for active alignment, such as by placing the laser diode electrodes of the VCSEL on a surface of the VCSEL that is different from the surface connected to the slider, unlike conventional VCSELs. Briefly, and in some embodiments, the VCSEL described herein includes a multi-surface chip for mounting to a slider. A first surface of the chip faces the slider, a second surface of the chip is opposite the first surface, and a side surface on which two laser diode electrodes may be positioned or bonded. Because the laser diode electrodes are bonded or positioned on the side surfaces of the VCSEL, active alignment may be achieved during use of the VCSEL and devices incorporating the VCSEL. Additionally, the VCSEL described herein may simplify and reduce the cost of manufacturing sliders and HGAs incorporating the VCSEL.

[0015] 1 is a schematic, illustrative diagram of a particular embodiment of a magnetic media drive including a HAMR magnetic write head. Such a magnetic media drive may be a single drive / device or may include multiple drives / devices. For ease of illustration, a single disk drive is shown according to an embodiment. Disk drive 100 includes at least one magnetic disk 112 (sometimes referred to as at least one rotatable magnetic recording medium) supported by a spindle 114 and rotatable by a drive motor 118. The magnetic recording on each magnetic disk 112 is in the form of any suitable pattern of data tracks, such as an annular pattern of concentric data tracks (not shown) on magnetic disk 112.

[0016] At least one slider 113 is positioned near the magnetic disk 112. Each slider 113 supports a head assembly 121 (e.g., a read / record head assembly) that includes one or more read heads and one or more write heads, such as a HAMR write head. In operation, as the magnetic disk 112 rotates, the slider 113 moves radially in and out over the disk surface 122 so that the head assembly 121 can access different tracks of the magnetic disk 112 where the desired data is written. Each slider 113 is attached to an actuator arm 119 by a suspension 115. The suspension 115 provides a slight spring force that biases the slider 113 toward the disk surface 122. Each actuator arm 119 is attached to an actuator 127. The actuator 127 as shown in FIG. 1 can be a voice coil motor (VCM). The VCM comprises a coil movable within a fixed magnetic field, with the direction and speed of coil movement controlled by motor current signals supplied by a control unit 129 .

[0017] During operation of disk drive 100, the rotation of magnetic disk 112 creates an air bearing between slider 113 and disk surface 122, which exerts an upward force, or lift, on slider 113. The air bearing thus counteracts the slight spring force of suspension 115 and supports slider 113 a small, substantially constant distance away from and slightly above disk surface 122 during normal operation.

[0018] The various components of the disk drive 100 are operationally controlled by control signals generated by a control unit 129, such as access control signals and internal clock signals. Typically, the control unit 129 includes logic control circuits, storage means, and a microprocessor. The control unit 129 generates control signals for controlling 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 desired current profiles to optimally move and position the slider 113 to a desired data track on the magnetic disk 112. Write and read signals are communicated to and from the head assembly 121 by a recording channel 125. Certain embodiments of the magnetic media drive of FIG. 1 may further include multiple media, or disks, multiple actuators, and / or multiple sliders.

[0019] 2 is a schematic illustration of a particular embodiment of a cross-sectional side view of a HAMR write head 230 facing a magnetic disk 112. The HAMR write head 230 may correspond to a part of the head assembly 121 described in FIG. 1 or a recording head used in other magnetic media drives. The HAMR write head 230 includes a medium facing surface (MFS), such as an air bearing surface (ABS) or a gas bearing surface (GBS), facing the magnetic disk 112. As shown in FIG. 2, the magnetic disk 112 and the HAMR write head 230 move relatively (as they should change direction) in the direction indicated by the arrow 282.

[0020] The HAMR write head 230 includes a main pole 236 disposed between a front shield 234 and a rear shield 238. The main pole 236 may include a main pole tip 237 in the MFS. The main pole tip 237 may or may not include a front taper and / or a rear taper. A coil 260 around the main pole tip 236 excites the main pole tip 237 to generate a write magnetic field that affects the magnetic medium of the magnetic disk 112. The magnetic disk 112 may be rotatable. In some embodiments, the coil 260 is a helical structure or a set of one or more pancake structures. The front shield 234 and / or the rear shield 238 may act as a return pole for the main pole 236. The magnetic disk 112 is positioned adjacent to or below the HAMR write head 230. The magnetic field generated by the current in the coil 260 is used to control the magnetization direction of the bits in the magnetic disk 112.

[0021] The HAMR write head 230 includes a structure for heating the magnetic disk 112 in proximity to where the main pole tip 237 applies a magnetic write field to the storage medium. The waveguide 242 is positioned between the main pole 236 and the front shield 234. The waveguide 242 can include a core layer and a cladding layer surrounding the core layer. The waveguide 242 conducts light from a source 278 of electromagnetic radiation, which can be, for example, ultraviolet, infrared, or visible light. The light source 278 can be, for example, a laser diode or other suitable laser source for directing a light beam into the waveguide 242. A variety of suitable techniques can be used for coupling the light source 278 to the waveguide 242. For example, the light source 278 can work in combination with an optical fiber and external optics to direct a light beam into the waveguide 242. Alternatively, the light source 278 can be attached to the waveguide 242 and the light beam can be directly coupled into the waveguide 242 without the need for external optical configurations. When a beam of light is coupled into the waveguide 242 , the light propagates through the waveguide 242 and heats a portion of the media as it moves relative to the HAMR write head 230 , as indicated by arrow 282 .

[0022] The HAMR write head 230 includes a near-field transducer (NFT) 284 for concentrating heat near the end of the waveguide 242. The NFT 284 is positioned in or adjacent to the waveguide 242 near or at the MFS. Light from the waveguide 242 is absorbed by the NFT 284 and travels along the outside of the NFT 284 toward the MFS, exciting surface plasmons that concentrate charge at the tip of the NFT 284, which then capacitively couples to the magnetic disk and heats a precise region of the magnetic disk 112 by Joule heating. One possible design for the NFT 284 of the HAMR write head is a lollipop design with a peg that extends between the disk portion and the disk and the MFS. The NFT 284 can be positioned close to the main pole 236. The NFT 284 can be relatively thermally isolated and can absorb a significant portion of the laser power while resonating.

[0023] The magnetic media drives and HAMR write heads discussed above can use various embodiments of the VCSELs and HGAs described below.

[0024] Exemplary VCSELs and HGAs The embodiments of the present disclosure also relate to VCSELs and HGAs incorporating VCSELs. VCSELs have many important advantages over edge emitting laser diodes (EELDs) for use as the light source for HAMR. Currently used EELDs are typically mounted on a submount due to the difficulty of directly bonding the edge emitting facet surface of the laser to the top of the slider. This submount is then bonded to the slider. In contrast, conventional VCSELs have mating electrodes on their front emitting surface that match corresponding electrodes on the top surface of the slider. These electrodes can be bonded by laser assisted solder reflow and also serve as electrical connections to energize the laser. Eliminating the need for a submount can significantly reduce light source costs.

[0025] Although conventional VCSELs offer reduced cost and no mode hopping compared to other lasers, such as edge-emitting laser diodes (EELDs), conventional VCSELs do not allow for active alignment. This is a result of the VCSEL's laser diode electrodes being connected to or facing the top surface of the slider. The embodiments described herein, unlike state-of-the-art VCSELs, allow for active alignment.

[0026] FIG. 3A shows the surface of a VCSEL 300 chip according to some embodiments. Although the VCSEL 300 is shown to have a rectangular prism form, other suitable forms or shapes, such as a cube, are contemplated. The VCSEL 300 has a first surface a (e.g., bottom surface) that can be directly or indirectly bonded to a slider, and a second surface b (e.g., top surface) opposite the first surface a. One or more of the other surfaces - a third surface c (e.g., back surface), a fourth surface d (e.g., side surface), a fifth surface e (e.g., side surface), and a sixth surface f (e.g., front surface) - are utilized to position or bond one or more laser diode electrodes (not shown) thereon in any combination. The third surface c, the fourth surface d, the fifth surface e, and the sixth surface f are side surfaces of the VCSEL 300. The number of laser diode electrodes positioned on or coupled to one or more side surfaces of the VCSEL can be any suitable number, such as one or two laser diode electrodes, such as one, two, three, four, five, or six laser diode electrodes.

[0027] In some embodiments, two laser diode electrodes are positioned on or coupled to the same side surface. For example, two laser diode electrodes can be positioned on or coupled to the third surface c, two laser diode electrodes can be positioned on or coupled to the fourth surface d, two laser diode electrodes can be positioned on or coupled to the fifth surface e, or two laser diode electrodes can be positioned on or coupled to the sixth surface f.

[0028] In some embodiments, one laser diode electrode is positioned on or coupled to one surface of the VCSEL and another laser diode electrode is positioned on or coupled to a different surface of the VCSEL in any combination. For example, by way of non-limiting example, one laser diode electrode can be positioned on or coupled to the third surface c and the other laser diode electrode can be positioned on or coupled to the fourth surface d, or one laser diode electrode can be positioned on or coupled to the third surface c and the other laser diode electrode can be positioned on or coupled to the fifth surface e. Other orientations for coupling the laser diode electrodes to the VCSEL 300 are also contemplated.

[0029] The VCSELs described herein may have a variety of dimensions. For example, in some embodiments, the bottom surface (e.g., first surface a) and top surface (e.g., second surface b) of the VCSEL have a height of about 75 μm to about 150 μm and / or a length of about 100 μm to about 250 μm. The side surfaces of the VCSEL may have the same or similar dimensions. The width of the bottom surface (e.g., first surface a) and top surface (e.g., second surface b) may be about 100 μm to about 250 μm, such as about 150 μm to about 200 μm, and / or the length of the bottom surface (e.g., first surface a) and top surface (e.g., second surface b) may be about 100 μm to about 250 μm, such as about 150 μm to about 200 μm. Smaller or larger dimensions of the VCSEL are contemplated. The dimensions of the various surfaces may be the same or different.

[0030] 3B and 3C are schematic side and bottom view illustrations, respectively, of a VCSEL 300 according to some embodiments. As explained above, the VCSEL 300 has one or more laser diode electrodes on a side surface. In the non-limiting example shown in FIG. 3B, the VCSEL 300 has two laser diode electrodes 305 (306) positioned on or coupled to side surface e.

[0031] As shown in FIG. 3C, a plurality of laser apertures 308a-308n are disposed on the bottom surface a of the VCSEL 300. It is contemplated that a single laser aperture may be utilized instead of the plurality of laser apertures. The number of laser apertures 308a-308n corresponds to the number of spot size converters in the slider. Each laser aperture 308a-308n may be spaced a distance 312 of about 1 μm to about 20 μm, such as about 2 μm to about 10 μm, from an adjacent laser aperture. Longer or shorter distances 312 are contemplated. The laser apertures 308a-308n may be aligned about a centerline, and the plurality of laser apertures 308A-308n may be aligned to corresponding input lasers. The laser apertures 308a-308n may also be aligned with corresponding laser apertures in the cavity (not shown). As shown in FIG. 3C, two laser diode electrodes 305, 306 extend from a side surface e of the VCSEL 300 to a bottom surface a.

[0032] Each of the laser apertures 308a-308n may independently have a diameter of about 1.5 μm to about 8 μm and a pitch of 2 μm to 10 μm, although larger or smaller diameters and pitches are contemplated. The centers of the laser apertures 308a-308n may be spaced apart from the sides by a distance 322 of about 35 μm to about 50 μm, although larger or smaller distances 322 are contemplated. The centers of the laser apertures 308a-308n may be spaced apart from the sides by a distance 324 of about 75 μm to about 90 μm from the laser diode electrodes 305, 306, although larger or smaller distances 324 are contemplated.

[0033] 4A and 4B are schematic illustrations 400 of cross-sectional views (in the down-track and cross-track directions, respectively) of a slider 404 with a VCSEL 410 chip attached thereto, according to some embodiments. The schematic illustrations shown in FIGS. 4A and 4B may be a portion of an HGA. For clarity, certain features are not labeled in FIG. 4B. A laser diode electrode 405 is bonded to or located on a side surface of the VCSEL 410. Although only one laser diode electrode 405 is shown bonded to the side surface 410e, another laser diode electrode (e.g., the laser diode electrode 406 shown in FIG. 6A) is bonded to the same side surface 410e of the VCSEL 410. The laser diode electrodes 405, 406 extend from the side surface 410e of the VCSEL 410 to the bottom surface 410a of the VCSEL 410, as shown in FIGS. 6A and 6B.

[0034] 4A, the VCSEL 410 is attached to the slider 404 via pad 401, pad 402, and soldering material 403. Pad 401 and pad 402 can each independently be a metal-containing layer. The slider 404 includes a substrate, e.g., an AlTiC substrate, and layer 424, e.g., an alumina-containing layer. Pad 401 is bonded to a lower surface 410a of the VCSEL 410, and pad 402 is bonded to an upper surface 404a of the slider 404. Pad 401, pad 402, and soldering material 403 can collectively form a contact after soldering. In addition to or instead of the soldering material 403, a conductive adhesive can be used.

[0035] The VCSEL 410 includes one or more cavities 415a-n through which one or more laser beams exit the VCSEL 410 and enter a single output waveguide 416 positioned within layer 424. Any suitable number of cavities may be used, such as, for example, from about 1 to about 16, such as, for example, from about 3 to about 12. More or fewer cavities are also contemplated. Each of the one or more laser beams emitted by the VCSEL 410 may operate at the same frequency and may be phase coherent. Each laser of the one or more laser beams emitted by the VCSEL 410 may have a power level of about 0.5 mW to about 20 mW, such as from about 1 mW to about 10 mW, such as from about 2 mW to about 8 mW, such as from about 4 mW to about 6 mW. More or fewer power levels are also contemplated. Although not shown, a multi-mode interference (MMI) device may be used and disposed within the slider 404. When used, the MMI device combines the laser light provided from the cavities 415a-414n and emits a single laser through a single output waveguide 416. The single output waveguide 416 can emit laser light from the MMI device that includes the combined power of the multiple input lasers accepted by the MMI device. The single output mode can be utilized to concentrate the optical power and couple it into the NFT.

[0036] A slider pad 425 is bonded to a surface of layer 424 of slider 404. Slider pad 425 is bonded to a multi-layer structure including a first polyimide layer 430, an electrode 409, a second polyimide layer 432, and a flexure 419. Bonding of slider pad 425 to the multi-layer structure can be accomplished by soldering material 407. In addition to or instead of soldering material 407, a conductive adhesive can be used.

[0037] The suspension (part of which is shown) that supports the slider 404 is disposed on the same surface as the pad 402 of the slider 404, e.g., on the top surface 404a. The suspension includes a flexure 419 and a load beam 417. The load beam is the main body of the suspension. The flexure 419 holds the slider 404, and the flexure 419 is fixed to the load beam 417. In operation, the load beam 417 can push the slider 404 towards a disk that has dimples 418. Between the flexure 419 and the slider 404, a polyimide layer 420 containing wires and / or electrodes (e.g., electrode 440) is disposed. The polyimide layer 420 containing wires is for applying current or voltage to components in the slider (e.g., magnetic head, heater for gap control, etc.) or for transmitting signals from sensors (reader, contact sensor, thermal sensor) to the preamplifier.

[0038] FIG. 5 is a perspective view of a portion of a thermally assisted magnetic recording head gimbal assembly 500. The head gimbal assembly 500 includes the VCSEL structure shown in FIGS. 4A and 4B, however, it is contemplated that the head gimbal assembly may be used with other VCSEL structures as described and shown herein. The head gimbal assembly 500 includes a suspension 501 including a flexure 419 and a load beam 417 as discussed above. A polyimide layer 420 including wires is positioned between the flexure 419 and a slider 404. A VCSEL 410 mounted on the slider 404 is positioned next to the polyimide layer 420. The flexure 419 includes electrodes 503, 505. In the configuration shown in FIG. 5, the VCSEL is positioned on the slider such that the laser diode electrode 405 and the laser diode electrode 406 can be coupled to electrodes 503a and 503b, respectively. The electrodes 503a, 503b function to supply current to the laser diode electrodes. Electrode 505 is coupled to the slider pad and functions to apply current or voltage to components in the slider (e.g., magnetic head, heater for spacing control, etc.) or to transmit signals from sensors (reader, contact sensor, temperature sensor) to the preamplifier. Electrode 440 shown in FIG. 4B corresponds to electrode 503a, and electrode 409 in FIG. 4A corresponds to electrode 505. Soldering material 434 can be used to couple electrode 440 to laser diode electrode 405, as shown in FIG. 4B.

[0039] 6A and 6B are schematic perspective and bottom view illustrations of the VCSEL 410 chip shown in FIGS. 4A and 4B. FIGS. 6C and 6D illustrate non-restrictive variations of the VCSEL 410 chip. In the orientations shown in FIGS. 6A-6D, the laser diode electrodes 405, 406 are positioned on or bonded to the side surface 410e of the VCSEL 410. The laser diode electrodes 405, 406 extend from the side surface 410e of the VCSEL 410 to the bottom surface 410a of the VCSEL 410. The pads 401 disposed on the bottom surface 410a of the VCSEL 410 are utilized to bond the VCSEL 410 to a slider, for example, slider 404. In some embodiments, the cavities 415a-414n of the VCSEL 410 include an active layer and two reflector layers, such as distributed Bragg reflectors, sandwiching the active layer. The laser diode electrodes 405, 406 may be connected to one of the reflector layers or the substrate.

[0040] The number and width of the trenches in which the electrodes are located may vary with respect to the variations in VCSEL 410, 610, 620. In the case of VCSEL 410 shown in Figure 6A, a first trench 601 in which a portion of laser diode electrode 405 is located is separated from a second trench 602 in which laser diode electrode 406 is located.

[0041] With reference to the VCSEL 610 shown in FIG. 6C, the laser diode electrodes 405, 406 are disposed within a single trench 612 having a width smaller than that of the VCSEL 610. Similarly, with respect to the VCSEL 620 shown in FIG. 6D, the laser diode electrodes 405, 406 are disposed within a single trench 622 having a width the same or substantially the same size as that of the VCSEL 620. Similar to the VCSEL 410, the VCSELs 610 and 620 can be positioned on a slider (e.g., slider 404) via pad 401. Additionally, the laser diode electrodes 405 and 406 of the VCSELs 610 and 620 can be coupled to the electrodes 503a, 503b of the HGA, as with the VCSEL 410.

[0042] 7A and 7B are schematic illustrations of a perspective view and a bottom view, respectively, of a VCSEL 710 chip. Various elements in FIGS. 7A and 7B, such as pads 401, cavities 415a-n, and electrodes 503a, 503b on the suspension, may be the same or similar to those described above in connection with FIGS. 4A and 4B. In the orientation shown in FIGS. 7A and 7B, laser diode electrodes 705, 706 are positioned on or bonded to two different surfaces of the VCSEL 710 - side surfaces 710e and 710d, respectively. The laser diode electrodes 705, 706 extend from their respective side surfaces to the bottom surface 710a of the VCSEL 710.

[0043] Referring to FIG. 7B, the laser diode electrode 705 is coupled to the electrode 503a of the suspension of the HGA (e.g., head gimbal assembly 500), and the laser diode electrode 706 is coupled to the electrode 503b of the suspension. The pad 401, located on the lower surface 710a of the VCSEL 710, is utilized to couple the VCSEL 710 to a slider. The VCSEL 710 may be positioned on a slider, such as the slider 404 shown in FIGS. 4A and 4B, but with a different orientation of the laser diode electrodes 705, 706 relative to the slider. The nature, characteristics, and applications of the VCSEL 710 chip (e.g., HGA assembly, magnetic media drive, etc.) may be the same as or similar to the nature, characteristics, and applications of the VCSEL 410 chip described above.

[0044] FIG. 8A is a schematic illustration of a side view 800 of a slider 804 with a VCSEL 810 chip attached, according to some embodiments. The schematic illustration 800 can be part of an HGA. FIGS. 8B and 8C are perspective and bottom views of the VCSEL 810 shown in FIG. 8A. FIGS. 8A-8C are a special case of a VCSEL where the laser diode electrode is located on the front surface 810f of the VCSEL 810. In these embodiments, the suspension can include a double layer electrode as shown in FIG. 8A, while the VCSEL410, VCSEL610, VCSEL620, and VCSEL710 include a single layer electrode on the suspension.

[0045] 8A, the VCSEL 810 is attached to the slider 804 via pad 801, pad 802, and soldering material 803. Pad 801 and pad 802 can each independently be a metal-containing layer. The slider 804 includes a substrate, e.g., an AlTiC substrate, and a layer 824, e.g., an alumina-containing layer. Pad 801 is bonded to a lower surface 810a of the VCSEL 810, and pad 802 is bonded to an upper surface 804a of the slider 804. Pad 801, pad 802, and soldering material 803 can collectively form a contact after soldering. In addition to or instead of the soldering material 803, a conductive adhesive can be used.

[0046] A laser diode electrode 805 is bonded to or positioned on a front surface (e.g., front surface 810f) of the VCSEL 810. Although only one laser diode electrode 805 is shown bonded to the front surface 810f, another laser diode electrode (e.g., laser diode electrode 806 shown in FIG. 8B) is bonded to the same front surface 810f of the VCSEL 810. The laser diode electrodes 805, 806 extend from the front surface 810f of the VCSEL 810 to the bottom surface 810a of the VCSEL 810, as shown in FIGS. 8B and 8C.

[0047] The VCSEL 810 includes one or more cavities 815a-n through which one or more laser beams exit the VCSEL 810 and enter a single output waveguide 816 located within the layer 824. Any suitable number of cavities may be used, for example, from about 1 to about 16, for example, from about 3 to about 12. More or fewer cavities are also contemplated. Each of the one or more laser beams emitted by the VCSEL 810 may operate at the same frequency and may be phase coherent. Each laser of the one or more laser beams emitted by the VCSEL 810 may have a power level of about 0.5 mW to about 20 mW, for example, from about 1 mW to about 10 mW, for example, from about 2 mW to about 8 mW, for example, from about 4 mW to about 6 mW. More or fewer power levels are also contemplated. Although not shown, a multi-mode interference (MMI) device may be used and disposed within the slider 804. When used, the MMI device combines the laser light provided from the cavities 815a-814n and emits a single laser through a single output waveguide 816. The single output waveguide 816 can emit laser light from the MMI device that includes the combined power of the multiple input lasers accepted by the MMI device. The single output mode can be utilized to concentrate the optical power and couple it into the NFT.

[0048] Referring to FIG. 8A, the slider pad 825 is bonded to a surface of layer 824 of slider 804. The slider pad 825 and the laser diode electrode 805 are bonded to a laminate structure including a bottom electrode 809a, a polyimide layer 811 disposed on the bottom electrode 809a, and a top electrode 809b disposed on the polyimide layer 811. Bonding the slider pad 825 and the laser diode electrode 805 to the multi-layer structure can be accomplished by soldering materials 807a and 807b, respectively. A conductive adhesive can be used in addition to or instead of the soldering materials 807a, 807b. Also, the laser diode electrode 806 is bonded to the multi-layer structure in the same or similar manner as the laser diode electrode 805.

[0049] The suspension (part of which is shown) that supports the slider 804 is placed on the same surface as the pads 802 of the slider 804, e.g., on the top surface 804a. A portion of the suspension is shown in FIG. 8A. The suspension includes a flexure 819 and a load beam 817. The load beam is the main body of the suspension. The flexure 819 holds the slider 804, and the flexure 819 is fixed to the load beam 817. In operation, the load beam 817 can push the slider 804 towards a disk that has dimples 818. Between the flexure 819 and the slider 804 is a polyimide layer 820 that includes wires. The wire layer is for applying current or voltage to components in the slider (such as a magnetic head, a heater for spacing control) or for transmitting signals from sensors (readers, contact sensors, thermal sensors) to the preamplifier. The bottom view of the VCSEL 810 (FIG. 8C) shows electrodes 821a, 821b on the suspension. In Figure 8C, electrodes 821a and 821b correspond to top electrode 809b. Figure 8C also illustrates the directional movement of, for example, VCSEL 810 in the cross-track and down-track directions.

[0050] One difference from Figure 4A is that the laser diode electrodes 805, 806 are not bonded to the multi-layer structure in the same manner as shown in Figure 4A. The VCSEL 810 may be positioned on the HGA in any suitable manner similar to that shown in Figure 5. The nature, characteristics, and applications of the VCSEL 810 chip (e.g., HGA assembly, magnetic media drive, etc.) may be the same as or similar to the nature, characteristics, and applications of the VCSEL 410 chip described above.

[0051] The VCSELs described herein allow for active alignment to maximize coupling between the waveguide (e.g., waveguide 242 or single output waveguide 816) and the laser during use, for example. The VCSELs described herein have output beams that are larger and more circular than those of EELDs, which increases alignment tolerances and coupling efficiency to the slider spot size converter. Additionally, the VCSELs described herein have mode-hop-free operation, for example, due to a very short cavity length with one longitudinal mode and DBR mirror selectivity, whereas EELDs suffer from mode hops. Mode hopping can suddenly cause slight changes in the laser output (typically 1-2%) during the recording process. VCSELs do not require burn-in during manufacturing, further reducing costs. The cavity length of the VCSEL is shorter than the EELD, and the laser is mounted on top of the slider, which reduces the overall height, reducing the spacing between the disks, and thus the number of disks and increasing the capacity of the HDD.

[0052] A trench or protrusion may be utilized around the metal pad (e.g., pad 401) for soldering. The solder between the VCSEL and the slider (e.g., slider 404) may expand during the soldering process and contact the laser diode electrode of the VCSEL. In some embodiments, and to prevent (or at least mitigate) the solder (e.g., soldering material 403) from contacting the laser diode electrode of the VCSEL, a trench or protrusion may be formed around the pad for soldering. The depth of the trench may be, for example, about 10 μm, but it may be larger or smaller. The height of the protrusion may be equal to the thickness of the metal layer plus the thickness of the solder, but it may be larger or smaller. In some embodiments, an insulating layer may be deposited on or near the trench or protruding area.

[0053] In some embodiments, at least one of the laser diode electrodes can be bonded to a pad for mounting when the pad is electrically isolated or grounded, for example, the spacing between the laser diode electrode and the mounting pad can be approximately zero.

[0054] Exemplary VCSELs with Recessed Features or Notches The embodiments described herein generally relate to VCSELs having concave features (notches) and HGAs incorporating such VCSELs. VCSELs with flat bottom surfaces, such as the VCSEL 910 chip in FIG. 9A, can sometimes cause electrical shorts. As shown in the schematic illustration 900 in FIG. 9A, the edge 908 of the laser diode electrode 905 contacts the insulating layer 901 positioned on the slider 904. A soldering material 934 is used to bond the laser diode electrode 905 to the suspension electrode 903. If the insulating layer 901 has a pinhole or crack, the soldering material can contact the slider 904 and cause an electrical short.

[0055] The inventors have found that a VCSEL having a concave feature or notch can eliminate or at least mitigate the occurrence of electrical shorts. FIG. 9B is a schematic illustration 950 of a cross-sectional view (cross-track direction) of a slider 404 with a VCSEL 410 chip attached thereto, according to some embodiments. The schematic illustration shown in FIG. 9B can be a portion of an HGA. Furthermore, the various features shown in the embodiment of FIG. 9B can be used with other embodiments described herein. A laser diode electrode 405 is bonded or positioned on a side surface of the VCSEL 410 chip. Although only one laser diode electrode 405 is shown, another laser diode electrode (e.g., the laser diode electrode 406 shown in FIG. 6A) can be bonded to the same side surface of the VCSEL 410. The laser diode electrodes 405, 406 can extend from the side surface 410e of the VCSEL 410 to the bottom surface 410a of the VCSEL 410, as shown in FIGS. 6A and 6B. The VCSEL 410 is attached to the slider 404 by pads and solder material (not shown) in addition to the solder material 954. As shown in Figure 9B, an insulating layer 951 is positioned between the slider 404 and the VCSEL 410. Solder material 954 is used to bond the laser diode electrode 905 to the suspension electrode 903.

[0056] The VCSEL 410 chip includes a notch 952 having a height (H1) and a depth (D1). The notch 952 has a width W1 (shown in FIG. 9C) that extends along at least a portion of the side surface 410e. The notch 952 has a shoulder 952a of depth D1 and a side 952b of height H1 that forms a concave edge 956 spaced apart from the slider 404 and the insulating layer 951. The notch 952 has an angle θ1 between the shoulder 952a and the side 952b. The shoulder 952a can be parallel or substantially parallel to the bottom surface 410a of the VCSEL 410 chip. The side 952b can be parallel or substantially parallel to the side surface 410e of the VCSEL 410 chip. Thus, the shoulder 952a and the side 952b can be vertical or substantially vertical. Each of the shoulder 952a and side 952b can be tapered or substantially tapered as desired. In other examples, the notch 952 can have other suitable shapes or profiles.

[0057] In some examples, as described further below in connection with Figures 9D and 9E, the shoulder 952a may not be parallel or substantially parallel to the bottom surface 410a of the VCSEL 410 chip, and / or the shoulder 952a and the side 952b may not be perpendicular or substantially perpendicular to one another.

[0058] The depth D1 of the notch 952 can be, for example, about 20 μm or less, such as about 10 μm or less, such as about 8 μm or less, such as about 5 μm or less, such as about 3 μm or less, although the depth D1 can be greater or less. In some embodiments, D1 is not necessarily uniform across the VCSEL 410 chip. D1 can be greater than 10 μm, such as about 10 μm to about 300 μm, such as about 20 μm to about 250 μm, about 15 μm to about 150 μm, or about 50 μm to about 200 μm, such as in some cases where D1 can extend across the entire width of the VCSEL 410 chip in some locations. The height H1 of the notch 952 can be greater than about 5 μm and / or less than about 50 μm, such as about 5 μm to about 15 μm, or about 20 μm to about 40 μm, although the height H1 can be greater or less. In some embodiments, the height H1 of each of the laser diode electrodes 405, 406 may be the same or different. For example, the height H1 of the laser diode electrode 405 may be greater than the height H1 of the laser diode electrode 406, or vice versa.

[0059] At least a portion of the laser diode electrode 405 is disposed on the surface of the VCSEL 410 chip such that the laser diode electrode 405 has a notch, i.e., the laser diode electrode 405 has a surface disposed on a shoulder 952a of the notch 952 and a different surface located on a side 952b of the notch 952.

[0060] As shown in FIG. 9B, the VCSEL 410 chip and attached laser diode electrode 405 are recessed relative to the position shown in FIG. 9A. Although not shown, pads (such as pad 401) are disposed on the bottom surface 410a of the VCSEL 410 and are used to bond the VCSEL to the slider 404. Such an arrangement is shown in FIG. 4B. In addition, the laser diode electrode 405 may be slightly recessed relative to the pad 401 (also shown in FIG. 4B). As shown in FIG. 9B, the pad 401 disposed on the bottom surface 410a of the VCSEL 410 is utilized to bond the VCSEL 410 to a slider, e.g., slider 404. The soldering material 954 bonding the suspension electrode 953 to the laser diode electrode 405 fills a portion of the recessed edge 956 such that the soldering material does not touch the insulating layer 951. The negative space (or empty space) that exists between the soldering material 954 and the insulating layer 951 can prevent or at least mitigate the occurrence of an electrical short. The height H3 refers to the height or distance between the top surface of the suspension electrode 953 and the top surface of the insulating layer 951 or the slider 404. In some examples, the notch height (H1) is the same as or close to the height H3. The height of the notch (H1) may be greater or less than H3, such as when H1 is about H3±10 μm to about H3±30 μm, such as about H3±10 μm to about H3±20 μm. However, the height of the notch (H1) may be greater or less, for example, based on the height of the suspension electrode 953 or the size of the soldering material 934.

[0061] The spacing between the lower surface of the laser diode electrode 405 and the insulating layer 951 or the upper surface of the slider 404 may be the same or different. As shown in FIG. 9B, the lower surface (bottom surface) of the laser diode electrode 405 touches the insulating layer 951 or the upper surface of the slider 404. In some cases, there may be a spacing between the lower surface of the laser diode electrode 405 and the insulating layer 951 or the upper surface of the slider 404. The VCSEL 410 chip is attached to the slider using contact pads (e.g., pads 801), and the laser diode electrode 405 may be slightly recessed relative to the contact pads.

[0062] In some examples, for example, the distance between the laser aperture (e.g., the multiple laser apertures 308a-308n) and the slider (e.g., the slider 404) can be minimized to increase the coupling efficiency between the laser and the waveguide (e.g., the waveguide 242 or the single output waveguide 816). That is, the lack of a gap between the laser diode electrode 405 and the insulating layer 901 or the slider 404 cannot be used to increase the coupling efficiency between the laser and the waveguide.

[0063] In another example, there may be a gap between the contact pad (e.g., pad 801) and the insulating layer 901 (or slider 404), such as when the laser diode electrode 405 touches the insulating layer 901 (or slider 404), which may reduce the adhesive strength between the pad 801 and the insulating layer 901 (or slider 404). To mitigate or avoid this problem, the bottom surface of the laser diode electrode 405 may be slightly concave (e.g., about 0.2 μm to about 2 μm, e.g., about 0.5 μm to about 1 μm) with respect to the pad 801, so that the bottom surface of the laser diode electrode 405 is always on the pad 801. In such a case, for example, there may be a small gap between the laser diode electrode 405 and the top surface of the insulating layer 951 (or slider 404). Additionally or alternatively, the gap between the bottom surface of each of the laser diode electrodes 405, 406 and the top surface of the insulating layer 901 (or slider 404) may be the same or different. For example, if laser diode electrode 405 is connected to the upper reflective layer and laser diode electrode 406 is connected to the lower reflective layer or substrate, the spacing between laser diode electrode 405 and slider 404 may be smaller than the spacing between laser diode electrode 406 and slider 404, or vice versa.

[0064] FIG. 9C is a schematic illustration 980 of a perspective view of the VCSEL 410 chip shown in FIG. 9B. In the orientation shown in FIG. 9C, the laser diode electrodes 405, 406 are positioned on or bonded to the side surface 410e of the VCSEL 410. The laser diode electrodes 405, 406 extend from the side surface 410e of the VCSEL 410 to the bottom surface 410a of the VCSEL 410. As shown in FIG. 9B, the pads 401 disposed on the bottom surface 410a of the VCSEL 410 are utilized to bond the VCSEL 410 to a slider, for example, slider 404. The laser diode electrodes 405, 406 are disposed in a single trench 982 having a width W1 that is the same size or substantially the same size as the width of the VCSEL 410. Alternatively, the laser diode electrodes 405, 406 can be disposed in different trenches. The width W2 represents the center-to-center of the laser diode electrodes 405, 406. In some examples, width W2 can be about 25% to about 65% of W1, such as about 35% to about 55%, such as about 40% to about 50%, of W1, although width W2 can be larger or smaller. Height H5 can be about 20 μm to about 300 μm, such as about 100 μm to about 150 μm, such as about 50 μm to about 250 μm, such as about 75 μm to about 200 μm, although height H5 can be larger or smaller. As with other VCSELs described herein, laser diode electrodes 405 and 406 of VCSEL 410 can be coupled to electrodes 503a, 503b of the HGA.

[0065] As described above, the notch 952 has a shoulder 952a, a side 952b, and an angle θ1. FIGS. 9D and 9E are schematic illustrations 985 and 990, respectively, of the VCSEL 410 chip shown in FIG. 9B, in which the shoulder 952a and the side 952b are not vertical or are not substantially vertical. That is, the angle θ1 may not be 90° or may not be substantially 90°. In some examples, the angle θ1 may be about 120° to about 140°, such as about 90° to about 180°, such as about 95° to about 170°, such as about 100° to about 160°, such as about 110° to about 150°, more than about 90° and / or less than about 180°. For clarity, only certain features are labeled in FIGS. 9D and 9E. FIG. 9E also indicates that the shoulder 952a may not be parallel or substantially parallel to the bottom surface 410a of the VCSEL 410 chip.

[0066] In some embodiments, which may be combined with other embodiments, the angle θ1 shown in any of FIGS. 9B-9E may be any suitable angle, such as about 0° to 270°, such as 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, or ... , 120°, 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160°, 165°, 170°, 175°, 180°, 185°, 190°, 195°, 200°, 205°, 210°, 215°, 220°, 225°, 230°, 235°, 240°, 245°, 250°, 255°, 260°, 265°, 270°, etc., or ranges therein. Each of the foregoing values ​​can be preceded by the words "about," "at least about," "less than about," or "greater than about," and any of the foregoing values ​​can be used alone to describe open-ended ranges or in combination to describe closed-ended ranges.

[0067] In at least one embodiment, the shoulder 952a and the side 952b are a continuous flat surface such that the shoulder 952a and the side 952b are not distinct. In such an example, the angle θ1 is 180°.

[0068] In at least one embodiment, the angle θ1 is greater than 180°, such as greater than or equal to about 180° and / or less than or equal to about 270°, such as from about 190° to about 260°, such as from about 200° to about 250°, such as from about 210° to about 240°, such as from about 220° to about 230°, etc.

[0069] FIG. 9F is a schematic illustration 995 of an example of a VCSEL 410 chip having two or more notches. Although two notches are shown, the VCSEL 410 chip may have more than two notches, such as three or four notches. For clarity, only certain features are labeled in FIG. 9F. Notch 952 is shown. A second notch 955 is also shown to have the same general features as notch 952. For example, the second notch 955 has a shoulder 955a of depth D2 and a side 952b of height H2 that forms a concave edge 957 spaced from the slider 404 and the insulating layer 951. The second notch 955 has an angle θ2. The shoulder 955a can be parallel or substantially parallel to the bottom surface 410a of the VCSEL 410 chip. The side 955b can be parallel or substantially parallel to the side surface 410e of the VCSEL 410 chip. Thus, the shoulder 955a and the side 955b can be vertical or substantially vertical. Each of the shoulder 955a and the side 955b can be tapered or substantially tapered as desired. In other examples, the second notch 955 can have other suitable shapes or profiles.

[0070] In some examples, in a manner similar to that described above with respect to the notch 952 (FIGS. 9D and 9E), the shoulder 955a may not be parallel or substantially parallel to the bottom surface 410a of the VCSEL 410 chip, and / or the shoulder 955a and the side 955b may not be perpendicular or substantially perpendicular to each other, i.e., the angle θ2 may not be 90° or may not be substantially 90°.

[0071] In some examples, the angle θ2 can be greater than or equal to about 90° and / or less than or equal to about 180°, such as from about 90° to about 180°, such as from about 95° to about 170°, such as from about 100° to about 160°, such as from about 110° to about 150°, such as from about 120° to about 140°, etc. In some embodiments that can be combined with other embodiments, the angle θ2 shown in FIG. 9F can be any suitable angle, such as from about 0° to 270°, such as 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, etc. , 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160°, 165°, 170°, 175°, 180°, 185°, 190°, 195°, 200°, 205°, 210°, 215°, 220°, 225°, 230°, 235°, 240°, 245°, 250°, 255°, 260°, 265°, 270°, etc., or ranges thereof. Each of the foregoing values ​​can be preceded by the words "about," "at least about," "less than about," or "greater than about," and any of the foregoing values ​​can be used alone to describe open-ended ranges or in combination to describe closed-ended ranges.

[0072] In some examples, the angles θ1 and θ2 may be the same or different. Various features of Figures 9A, 9B, 9C, 9D, and 9F may be combined as desired.

[0073] The recessed features, or notches, can be fabricated in the VCSELs described herein by one or more of the fabrication processes described below. For example, shallow trench 1505a in Figure 15 can correspond to trench 982 in Figure 9C.

[0074] Exemplary Fabrication Process The present disclosure also relates to fabrication processes for forming a portion of one or more of the VCSELs described herein. Figure 10A is a process flow diagram illustrating selected operations on a substrate during an exemplary process 1050 (Figure 10B) for forming electrodes on side surfaces of a VCSEL.

[0075] The process begins with selecting a substrate 1000a. The substrate may be formed from a suitable substrate material 1001. Suitable materials for the substrate material 1001 include, but are not limited to, Ga, As, Al, In, alloys thereof, and combinations thereof. Exemplary materials suitable for the substrate material 1001 include, but are not limited to, GaAs, AlAs, AlGaAs, InGaAs, InGaAsN, GaAsN, GaAsP, InP, InGaAsP.

[0076] Then, in operation 1055, the substrate material 1001 is etched by a suitable method to form trenches 1005. This etching process to form wafer 1000b can be a single-step etching process or a multi-step etching process (e.g., a two-step etching process, a three-step etching process, or more steps). The areas etched in each step of the multi-step etching process can be different. The etching can be performed by dry etching plasma utilizing wet etchants, ion milling, reactive ion etching, reactive ion beam etching, or combinations thereof. The etching process of operation 1055 can be performed to form n trenches of n depths. For example, a first trench having a first depth can be formed, a second trench having a second depth can be formed, a third trench having a third depth can be formed, etc. The trench depths can be the same or different. As a non-limiting example of operation 1055, the etching process may be accomplished by reactive ion etching utilizing a suitable etchant material such as a chlorine-containing material (e.g., HCl and / or Cl2), although any number of gases or mixtures thereof may be used. A non-reactive gas, for example a carrier gas such as argon, may be utilized during the etching process of operation 1055.

[0077] A seed layer 1010 comprising a suitable conductive material, for example, copper (Cu), chromium (Cr), titanium, nickel (Ni), a noble metal (e.g., ruthenium (Ru), rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt), and / or gold (Au)), or combinations thereof, may then be deposited in operation 1060 to form the wafer 1000c. Other metals are also contemplated. In some embodiments, the seed layer 1010 may be deposited as a single layer or as multiple layers, where, for example, different metals may be used for each individual layer of the multiple layers of the seed layer 1010. Additionally or alternatively, the single layer or multiple layers of the seed layer 1010 may include an alloy of two or more such metals. The seed layer 1010 is deposited within the trench 1005, on one or more sidewalls of the trench 1005, and / or on a surface of the substrate extending over the trench 1005. The seed layer formed in act 1060 can become an electrode of a VCSEL. When the metal electrode is deposited by a method other than plating, the seed layer is typically referred to as an underlayer.

[0078] The deposition of operation 1060 may be performed by any suitable technique, such as sputtering, atomic layer deposition (ALD), and / or ion beam deposition (IBD). In addition to or as an alternative to sputtering, ALD, and / or IBD, other suitable metal deposition techniques for depositing the seed layer 1010 may be utilized, such as e-beam and / or resistive evaporation. The directionality of the deposition may be controlled when using IBD, examples of which are shown in various exemplary process schemes in FIGS. 13-16 discussed below (as indicated by arrows 1307, 1407, 1507, and 1607 in the respective figures). In general, IBD may be used when it is not desired to form a layer of material across the entire trench. Although IBD is shown in various process schemes, additional or alternative deposition techniques may be utilized to those described herein. Angled deposition may also be used for electrode deposition.

[0079] In some embodiments, prior to depositing the seed layer 1010, an insulating layer (e.g., SiO2 and / or Al2O3) may be deposited on at least a portion of the wafer 1000b, such as in the trench 1005, one or more sidewalls of the trench 1005, and / or a surface of the substrate extending over the trench 1005. The seed layer 1010 may then be deposited, if desired, on at least a portion of this insulating layer. The insulating layer may, for example, enable isolation of the laser diode electrodes.

[0080] Then, in operation 1065, a photoresist material 1015 can be patterned on the wafer 1000c by a suitable photolithography process on at least a portion of the seed layer 1010. The photoresist material 1015 can be formed using spray coating, spin coating, and / or other suitable methods. The wafer 1000d with the photoresist material disposed thereon is utilized to control plating of a metal-containing layer in a subsequent operation discussed below. In some embodiments, the thickness of the photoresist material 1015 can be selected such that the photoresist material 1015 is removed in a subsequent operation (e.g., a post-plating operation) and can range, for example, from about 3 μm to about 15 μm, such as from about 4 μm to about 12 μm in thickness. Photoresist material 1015 having a larger or smaller thickness is contemplated. If desired, a plasma clean can be performed using, for example, O2 and / or water in combination with ammonium hydroxide (NH4OH) to clean some or all of the photoresist remaining in the undesired portions of the seed layer 1010.

[0081] Once the open areas defined by the photoresist material 1015 are formed, then in operation 1070, a metal plate 1020 is deposited by a suitable method on at least a portion of the wafer 1000d to form a wafer 1000e. For example, the metal plate 1020 can be plated on at least a portion of the seed layer 1010, such as on the surface of the seed layer 1010 over the trench 1005, as well as on the portion of the seed layer within the trench or its sidewalls. The metal plate 1020 can include a non-metal. Illustrative examples of metals useful for operation 1070 include the metals discussed above for the seed layer, such as, by way of non-limiting examples, Au, Cu, Pd, Pt, or combinations thereof, although other metals are contemplated. The thickness of the metal plate 1020 can vary. In some embodiments, the thickness of the metal plate 1020 is from about 1 μm to about 15 μm, such as from about 2 μm to about 10 μm, such as from about 3 μm to about 5 μm. Larger or smaller thicknesses of the metal plate 1020 are contemplated.

[0082] The metal plate 1020 can be deposited by plating, although other deposition methods such as sputtering, vacuum evaporation, and / or ion beam deposition (IBD) can also be used. If sputtering, vacuum evaporation, and / or IBD are used, operation 1060 (forming the seed layer 1010) can be skipped, if desired. As explained above, IBD can be used to control the directionality of deposition of the metal plate 1020. For example, as shown in Figures 13-16, the directionality of IBD can be the same or similar to that shown for the deposition of the seed layer (indicated by arrows 1307, 1407, 1507, and 1607 in the respective figures).

[0083] Then, in operation 1075, at least a portion of the photoresist material 1015 and / or at least a portion of the seed layer 1010 are removed from wafer 1000e by a suitable method, such as milling. As illustrated by wafer 1000f, the portions of seed layer 1010 removed during operation 1075 may include portions previously disposed under the photoresist material 1015.

[0084] The milling process of operation 1075 may be performed using a solvent, plasma cleaning, or a combination thereof. The wafer 1000f formed here includes various exposed surfaces, such as an exposed surface of the substrate material 1001, an exposed surface of the metal plate 1020, and / or an exposed surface of the seed layer 1010. If desired, operation 1075 may be performed in multiple operations, where at least a portion of the photoresist material 1015 is removed before at least a portion of the seed layer 1010. In some embodiments, a portion of the metal plate 1020 may be removed, for example, by milling, during or after the removal of the seed layer 1010. Because the thickness of the metal plate 1020 is greater than the seed layer 1010, the seed layer 1010 outside the area of ​​the metal plate 1020 is removed, but the metal plate 1020 remains.

[0085] Instead, in some embodiments, the seed layer 1010 can be patterned using photolithography prior to plating of the metal plate 1020 such that the exemplary process 1050 for forming a VCSEL does not require milling the seed layer 1010.

[0086] Optional operation 1080 may then be performed to deposit a resist coating 1025 on one or more exposed portions of the wafer 1000f to form the wafer 1000g. The resist coating 1025 may be formed using spray coating, spin coating, and / or other suitable methods. Non-limiting illustrative examples of photoresist types used for the resist coating 1025 may include UV negative resist, g / i-line positive resist, KrF positive resist, and / or ArF positive resist. As illustrated by the wafer 1000g, the deposition forms the resist coating 1025 on at least a portion of the metal plate 1020, at least a portion of the seed layer 1010, at least a portion of the substrate material 1001, or a combination thereof. The resist coating 1025 functions, for example, to protect the metal plate 1020, the seed layer 1010, the substrate material 1001, or a combination thereof during a subsequent dicing operation.

[0087] Wafer 1000g is then diced, sliced, cleaved, or otherwise cut into one or more individual chips 1000h in operation 1085. Here, and in some embodiments, the wafer is cut into individual dies along trenches 1005 using a blade, saw, scribe, laser dicing, stealth dicing, and / or other suitable equipment using a suitable method.

[0088] If one or more of the individual chips 1000h include a resist coating 1025 (e.g., formed during optional operation 1080), the resist coating 1025 may be removed after the dicing operation to form the wafer 1000i. Removal of the resist coating 1025 may be performed, for example, by immersing the wafer in a resist removal solution, placing the wafer in an O2 asher, and / or other suitable methods.

[0089] Other operations may include cleaning the wafer before and / or after one or more operations of the exemplary process 1050. Cleaning may be performed by any suitable method, such as immersion in a cleaning solution, ultrasonic cleaning, UV / O3 cleaning, brush cleaning, polishing, and / or CO2 cleaning.

[0090] Other illustrative, but non-limiting, exemplary process flow diagrams for forming laser diode electrodes on one or more side surfaces of a VCSEL are shown in Figures 11-17. The process of Figures 11-17 generally follows the flow chart illustrated in Figure 10B, however, the wafer formed after the optional deposition process of optional operation 1080 (e.g., to form resist coating 1025 of wafer 1000g) is not illustrated in Figures 11-17.

[0091] The general process scheme illustrated in Figures 11-17 includes the following operations: etching a trench, depositing a seed layer, patterning a photoresist layer, plating a metal, removing at least a portion of the photoresist layer and / or the seed layer, and dicing / cutting the wafer, embodiments and implementations of which are described elsewhere in this application.

[0092] Table I shows numerical listings corresponding to Figures 11-17 for various wafers and features formed during processing according to some embodiments. As discussed above, the directionality of seed layer deposition (operation 1060) can be controlled using IBD. Arrows 1307, 1407, 1507, and 1607 in Figures 13-16, respectively, illustrate the directionality of IBD as used during VCSEL processing. Although IBD is shown in various process schemes, additional or alternative deposition techniques can be utilized for seed layer deposition as described herein.

[0093] [Table 1]

[0094] 11, metal plate 1120 (e.g., electrode) is insulated from the laser diode electrode (e.g., laser diode electrode 405 and / or laser diode electrode 406 in FIG. 6B, laser diode electrode 705 and / or laser diode electrode 706 in FIG. 7B, or laser diode electrode 805 and / or laser diode electrode 806 in FIG. 8C). In some embodiments, metal plate 1120 can extend to the laser diode electrode or can be connected to the laser diode electrode via additional structure.

[0095] As illustrated in some process examples, multiple trenches can be formed, for example, to control the location of the bottom and / or side edges of the laser diode electrode. For example, as shown in FIG. 15, a two-step etch can be performed to form a shallow trench 1505a and a deep trench 1505b. In another example, and as shown in FIG. 16, a three-step etch can be performed to form a shallow trench 1605a, a first deep trench 1605b, and a second deep trench 1605c. The multi-step etch can be performed by any suitable method. Although the substrate / wafer shapes shown in the process flow diagrams are square or substantially square, other shapes are also contemplated. Similarly, various shapes of trenches and layers are contemplated.

[0096] 18A and 18B generally illustrate processing variations in accordance with at least one embodiment of the present disclosure. Specifically, FIG. 18A is a portion of a wafer 1800 showing the variable angle of the sidewall 1807 during processing, and FIG. 18B shows the location of the sidewall 1807 of a formed VCSEL 1850 after processing. The angled sidewalls can be formed by one or more of the etching processes described herein.

[0097] During processing, and as shown in FIG. 18A, the substrate can be etched to form a wafer 1800. The etching forms a trench 1805 having sidewalls 1807. An angle θ3 of the sidewalls 1807 can be selected to, for example, simplify etching, deposition of seed layer 1810, patterning of photoresist to form photoresist material 1815, metal deposition, and other process operations. For example, if the angle θ3 is zero, it may be difficult to expose the photoresist to the sidewalls. Selecting a non-zero value for the angle θ3 can make the sidewalls 1807 more suitable for photolithography and / or other process operations. By way of example, the angle θ3 can be from about 1° to about 10°, such as from about 5° to about 10°, although larger or smaller values ​​of the angle θ3 are also contemplated. Alternatively, the angle θ3 can be zero. 18A and 18B, the angle θ3 of the sidewall 1807 is measured from a normal α of the wafer 1810 or VCSEL 1850, respectively, which is perpendicular to the bottom surface 410a of the VCSEL (for clarity, the pad 401 is disposed on the bottom surface 410a).

[0098] FIG. 18B shows the location of sidewalls 1807 of the VCSEL 1850 after processing. Sidewalls 1807 can be formed by etching trench 1805 as described by the processes herein. Trench 1805 has a bottom surface 1805a, a top surface 1805b, a height H4 from bottom surface 1805a to top surface 1805b, and a depth D3. Depth D3 can be, for example, about 10 μm or less, such as about 3 μm or less, such as about 8 μm or less, such as about 5 μm or less, although depth D3 can be more or less. Height H4 can be about 30 μm or more, such as about 30 μm to about 100 μm, such as about 50 μm to about 90 μm, such as about 60 μm to about 80 μm, although height H4 can be more or less.

[0099] As illustrated, the laser diode electrodes 405, 406 are positioned on the sidewalls 1807 and within the trench 1805. The sidewalls 1807 may be a portion of the side surface 410e of the VCSEL 410, or other surfaces of the VCSEL described herein. The laser diode electrodes 405, 406 may extend to the bottom surface 410a of the VCSEL 410. The pads 401 are disposed on the bottom surface 410a. As described above, the laser diode electrodes 405, 406 may be formed after depositing a metal on the seed layer 1810, for example, by plating, sputtering, vacuum deposition, and / or IBD. If sputtering, vacuum deposition, and / or IBD are used, seed layer deposition may be skipped, if desired.

[0100] Angled side walls may also be utilized with one or more of the embodiments described herein.

[0101] FIG. 19 illustrates a process variation 1900 for etching a trench 1925 on a different side of a VCSEL, according to at least one embodiment of the present disclosure. Here, the opposite side of the VCSEL (side 1920 without laser diode electrode 1908) can be etched during VCSEL processing to form a trench 1925. This additional etch can be performed, for example, to increase the width of the trench to allow easier dicing of the substrate (the width of the dicing saw is illustrated by numerals 1910 and 1915). Additionally or alternatively, an additional etch can be performed to reduce the thickness of the deposited photoresist material, thereby allowing for a more conformal coating of the photoresist material. Furthermore, the additional etch can allow for easier exposure of the sidewalls to photoresist material during the photolithography process. The process variation illustrated in FIG. 19 can be utilized in conjunction with one or more of the process flow diagrams described herein.

[0102] Provided herein are VCSELs, HGAs for mounting the VCSELs, and devices incorporating such articles, such as magnetic media drives. Processes for fabricating the VCSELs are also provided. VCSELs with angled sidewalls and concave features are also described. The embodiments described herein differ from conventional VCSELs in that they allow for active alignment, for example, to maximize coupling between the waveguide and the laser during use.

[0103] In the foregoing, reference is made to embodiments of the present disclosure. However, it should be understood that the present disclosure is not limited to the specifically described embodiments. Instead, any combination of the features and elements described above, whether associated with different embodiments or not, is contemplated for implementing and practicing the present disclosure. Furthermore, while embodiments of the present disclosure may achieve advantages over other possible solutions and / or over the prior art, whether or not a particular advantage is achieved by a given embodiment does not limit the present disclosure. Thus, the above-described aspects, features, embodiments, and advantages are merely illustrative and are not considered elements or limitations of the appended claims unless expressly recited in the claims. Similarly, references to "the present disclosure" are not to be construed as a generalization of any inventive subject matter disclosed herein, and should not be considered elements or limitations of the appended claims unless expressly recited in the claims.

[0104] For the purposes of this disclosure, unless otherwise stated, all numerical values ​​in the detailed description and claims herein are modified by "about" or "approximately" the indicated value to account for experimental error and variation expected by those skilled in the art. For the sake of brevity, only certain ranges are expressly disclosed herein. However, a range from any lower limit may be combined with any upper limit to recite a range not expressly recited, and similarly, a range from any lower limit may be combined with any other lower limit to recite a range not expressly recited, and in the same manner, a range from any upper limit may be combined with any other upper limit to recite a range not expressly recited. In addition, within a range, all points or individual values ​​between its endpoints are included, even if not expressly recited. Thus, all points or individual values ​​may serve as their own lower or upper limits in combination with any other points or individual values ​​or any other lower or upper limits to recite a range not expressly recited.

[0105] As used herein, the indefinite article "a" or "an" is intended to mean "at least one" unless otherwise specified or clearly indicated otherwise by context.

[0106] While the above is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, which scope is determined by the following claims.

Claims

1. 1. A vertical cavity surface emitting laser (VCSEL) device, comprising:

1. A chip for mounting on a slider, the chip having a plurality of surfaces and a notch, the plurality of surfaces comprising: a lower surface facing the slider; an upper surface opposite said lower surface; a chip including a plurality of side surfaces; two laser diode electrodes positioned in any combination on one or more of the side surfaces; the notch forms a concave edge extending from the lower surface toward the upper surface, the notch having a shoulder, a side, and an angle (θ1) between the shoulder and the side; the shoulder is spaced from the slider; the side extends from the shoulder to the lower surface; At least a portion of a first laser diode electrode is positioned over the shoulder and the side of the notch.

2. the notch has a depth of about 10 μm to about 50 μm; The angle (θ1) is greater than 90° and less than 180°, or The VCSEL device of claim 1 which is a combination thereof.

3. The VCSEL device of claim 2, wherein the angle (θ1) is between about 100° and about 160°.

4. 2. The VCSEL device of claim 1, wherein the shoulder is substantially parallel to the lower surface and the side is substantially perpendicular to the shoulder.

5. 10. The VCSEL device of claim 1, wherein a second laser diode electrode is located on a side surface different from the side surface on which the first laser diode electrode is located.

6. The VCSEL device of claim 1 , wherein the two laser diode electrodes are located on the same side surface.

7. A magnetic media drive comprising the VCSEL device of claim 1.

8. 1. A vertical cavity surface emitting laser (VCSEL) device, comprising:

1. A chip for mounting on a slider, the chip having a plurality of surfaces, the plurality of surfaces comprising: a bottom surface of the chip facing the slider; and an upper surface of the chip opposite the lower surface; a chip including a plurality of side surfaces, a first side surface of the plurality of side surfaces being inclined at an angle (θ3) from a line (α) perpendicular to the lower surface; two laser diode electrodes positioned in any combination on one or more of the side surfaces of the chip; The angle (θ3) is greater than 0° and less than or equal to about 10°; At least one laser diode electrode is positioned on the first side surface.

9. 9. The VCSEL device of claim 8, wherein the angle (θ3) is less than or equal to about 5°.

10. 9. The VCSEL device of claim 8, wherein the two laser diode electrodes are located on the first side surface.

11. The VCSEL device of claim 8 , wherein the two laser diode electrodes are located on different side surfaces.

12. A magnetic media drive comprising the VCSEL device of claim 8.

13. 1. A head gimbal assembly, comprising: The suspension and a slider mounted on the suspension; a vertical cavity surface emitting laser (VCSEL) device mounted on the slider, A chip for mounting on the slider, the chip having a plurality of surfaces and a notch, the plurality of surfaces comprising: a bottom surface of the chip facing the slider; and a top surface of the chip opposite the top surface; a chip including a plurality of side surfaces; two laser diode electrodes positioned in any combination on one or more of the side surfaces of the chip; the notch forms a concave edge extending from the lower surface toward the upper surface, the notch having a shoulder, a side, and an angle (θ1) between the shoulder and the side; the shoulder is spaced from the slider; the side extends from the shoulder to the lower surface; At least a portion of a first laser diode electrode is positioned on the shoulder and the side of the notch.

14. The head gimbal assembly of claim 13 , wherein the two laser diode electrodes are connected to one or more electrodes of the suspension.

15. 14. The head gimbal assembly of claim 13, wherein the two laser diode electrodes are positioned on different side surfaces of the chip.

16. 14. The head gimbal assembly of claim 13, wherein the two laser diode electrodes are positioned on the same side surface of the chip.

17. A magnetic media drive comprising the head gimbal assembly of claim 13.

18. 1. A head gimbal assembly, comprising:

1. A vertical cavity surface emitting laser (VCSEL) device, comprising:

1. A chip for mounting on a slider, the chip having a plurality of surfaces, the plurality of surfaces comprising: a bottom surface of the chip facing the slider; and an upper surface of the chip opposite the lower surface; a chip including a plurality of side surfaces, a first side surface of the plurality of side surfaces being inclined at an angle (θ3) from a line (α) perpendicular to the lower surface; two laser diode electrodes positioned in any combination on one or more of the side surfaces of the chip; The angle (θ3) is greater than 0° and less than or equal to about 10°; a VCSEL device having at least one laser diode electrode positioned on the first side surface; a metal pad coupled to the bottom surface of the chip.

19. 20. The head gimbal assembly of claim 18, wherein the metal of the metal pad is bonded to the metal of at least one of the two laser diode electrodes.

20. the head gimbal assembly further comprising a suspension; 20. The head gimbal assembly of claim 18, wherein the two laser diode electrodes are connected to one or more electrodes of the suspension.

21. 20. A magnetic media drive comprising the head gimbal assembly of claim 18.

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