Coating of hard disk drive sliders for mechanical improvement of suspension

Abstract

To provide a method of manufacturing a hard disk drive (HDD) head gimbal assembly (HGA) that improves mounting and movability of a head slider, and an assembly.SOLUTION: A method includes: coating a first portion of a suspension surface of a head slider having a slider body with a recording medium surface facing the suspension surface and a leading edge (LE) surface connecting the suspension surface and the recording medium surface with an anti-reflective coating (ARC); and adhering the head slider to the suspension assembly with a flexure having standoff structure to which the suspension surface of the slider is attached, and positioning the ARC so as to extend to at least the farthest portion of the standoff structure of the flexure in a direction toward the LE surface.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the invention may relate generally to hard disk drives, and more particularly, to techniques for improving head slider mounting and mobility. [Background technology]

[0002] A hard disk drive (HDD) is a non-volatile storage device that stores digitally encoded data on one or more circular disks that have magnetic surfaces and are housed in a protective enclosure. When an HDD is in operation, each magnetic recording disk is rapidly rotated by a spindle system. Data is read from and written to the magnetic recording disks using a read-write head (or "transducer") that is positioned over specific locations on the disks by an actuator. The read-write head uses a magnetic field to write data to and read data from the surface of the magnetic recording disk. The write head works by generating a magnetic field using an electric current that flows through the coils of the write head. Electrical pulses are sent to the write head with different patterns of positive and negative currents. The electric current in the coils of the write head creates a localized magnetic field across the gap between the head and the magnetic disk, which then magnetizes small areas on the recording medium.

[0003] Increases in areal density (a measure of the amount of information bits that can be stored in a given area of ​​the disk surface) have led to the necessary development and implementation of secondary and even tertiary actuators for improved head positioning through relatively fine positioning, in addition to the primary voice coil motor (VCM) actuator, which provides relatively coarse positioning. Some HDDs use microactuator or milliactuator designs to provide second and / or third stage actuation of the recording head to enable more accurate positioning of the head relative to the recording track. Milli-actuators can be broadly classified as actuators that move the entire front end of the suspension, i.e., spring, load beam, flexure, and slider, and are typically used as second stage actuators. Micro-actuators (or "microactuators") can be broadly classified as actuators that move (e.g., rotate) only the slider, either moving the slider relative to the suspension and load beam, or moving only the read-write element relative to the slider body. A microactuator may be used in combination with only a first stage actuator (e.g., a VCM) or in combination with a first stage actuator and a second stage actuator (e.g., a milli-actuator) for more precise head positioning. The terms "microactuator" and "secondary actuator" and "dual stage actuator" are generally used herein to refer to a relatively fine positioning actuator (e.g., either secondary or tertiary in technology) used in combination with a primary relatively coarse positioning actuator, such as a VCM actuator in the context of HDDs. Piezoelectric (PZT)-based transducers and capacitive micromachined transducers are two types of microactuators developed for use with HDD sliders. However, mechanical tolerances within dual stage actuator systems are traditionally tight.

[0004] Any approach that may be described in this section is an approach that could be pursued, but not necessarily an approach that has been previously conceived or pursued, and thus, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. [Brief description of the drawings]

[0005] Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numbers refer to similar elements and in which: [Figure 1] 1 is a plan view showing a hard disk drive according to one embodiment. [Diagram 2] 1 is a perspective view of a heat-assisted magnetic recording (HAMR) head slider coupled to a laser module according to one embodiment. [Figure 3A] FIG. 1 illustrates a side view of a thermally assisted magnetic recording (HAMR) chip-on-submount assembly (CoSA) according to one embodiment. [Figure 3B] FIG. 3B is a cross-sectional perspective view of the HAMR CoSA of FIG. 3A, according to one embodiment. [Figure 4A] FIG. 1 illustrates a top view of a known slider-flexure assembly, according to one embodiment. [Figure 4B] FIG. 2 is a top view of a reinforced slider-flexure assembly according to one embodiment. [Diagram 5] 1A-1C are side views illustrating the slider-adhesive interface comparing a smooth uncoated surface to a rough coated surface according to one embodiment. [Figure 6A] FIG. 2 is a top view illustrating critical areas of clearance for a slider-flexure assembly according to one embodiment. [Figure 6B] FIG. 2 is a side view illustrating areas of clearance of a slider-flexure assembly according to one embodiment. [Figure 6C]FIG. 4B is a side view showing an ideal slider mounting of the known slider-flexure assembly of FIG. 4A. [Figure 6D] FIG. 4B is a side view illustrating an unstable slider mounting of the known slider-flexure assembly of FIG. 4A. [Figure 7] FIG. 4C is a side view illustrating a stable slider mounting of the enhanced slider-flexure assembly of FIG. 4B according to one embodiment. [Figure 8] 4 is a flow diagram illustrating a method for manufacturing a head gimbal assembly of a hard disk drive, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] Generally, an approach for improving the mounting and mobility of a head slider in a hard disk drive (HDD) is described. In the following specification, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention described herein. However, it will be apparent that the embodiments of the invention described herein may be practiced without these specific details. In other instances, well-known structures and devices may be shown in block diagram form in order to avoid unnecessarily obscuring the embodiments of the invention described herein.

[0007] introduction term References herein to "an embodiment," "one embodiment," and the like are intended to mean that the particular feature, structure, or characteristic being described is included in at least one embodiment of the invention. However, instances of such phrases do not necessarily all refer to the same embodiment.

[0008] It will be understood that the term "substantially" describes features that are largely or approximately structured, configured, dimensioned, etc., however, that manufacturing tolerances and the like may result in situations where in practice the structure, configuration, dimensions, etc. are not always or necessarily precisely as described. For example, if one were to describe a structure as being "substantially vertical," the term would be assigned its obvious meaning such that the sidewalls are for all practical purposes vertical, but may not be at exactly 90 degrees.

[0009] Terms such as "optimal," "optimize," "minimal," "minimize," "maximum," "maximize," and the like may not have a specific value associated with them, but when such terms are used herein, it is intended that one of ordinary skill in the art will understand that such terms include affecting values, parameters, metrics, and the like in a beneficial direction consistent with the entirety of this disclosure. For example, describing some value as a "minimum" does not require that the value actually be equal to a theoretical minimum (e.g., zero), but should be understood in a practical sense in that the corresponding goal would be to move the value in a beneficial direction toward the theoretical minimum.

[0010] context Recall that secondary and tertiary actuators are being developed and implemented for improved read-write head positioning with relatively fine positioning, and such dual stage actuator systems require tight mechanical tolerances throughout the associated slider suspension components. Furthermore, as previously mentioned, increasing the storage capacity of hard disk drives (HDDs) is a continuing goal in the evolution of HDD technology. In one form, this goal manifests itself in increasing areal density, such as through the use of heat-assisted magnetic recording (HAMR). In HAMR, a laser light source (e.g., a laser diode) is integrated into the magnetic recording head slider. Laser diodes are fragile and typically not suitable for direct mechanical attachment to the head slider. Thus, a submount assembly can be used to attach the laser diode to the slider body. Adding such HAMR components to a conventional head slider introduces additional mechanical tolerances and constraints into the slider-suspension design as well.

[0011] FIG. 2 is a perspective view showing a HAMR head slider coupled with a laser module according to an embodiment. The HAMR head slider assembly 200 includes a laser light source 204 (or simply "laser 204"), such as a semiconductor laser or laser diode, which is coupled to or integrally formed with a submount 206 for mounting to the HAMR head slider 202 and is utilized to locally heat a magnetic medium (e.g., see the recording medium 120 in FIG. 1). The combination of the laser 204 and the submount 206 is often collectively referred to as a "laser module" or a chip-on-submount assembly (CoSA) block or a CoSA laser module. In a non-limiting example, the HAMR laser module including the laser 204 and the submount 206 can be mounted on or near the back side of the HAMR head slider 202 (e.g., on the suspension side opposite the air bearing surface or ABS). This localized heating of the magnetic medium 120 momentarily reduces the local coercivity of the magnetic medium 120, making the medium 120 much easier to write to.

[0012] FIG. 3A is a side view of a heat-assisted magnetic recording (HAMR) chip-on-submount assembly (CoSA) according to one embodiment, and FIG. 3B is a cutaway perspective view of the HAMR CoSA of FIG. 3A according to one embodiment. In a HAMR design, a submount 206 is typically bonded to the flexure mating surface 202a of the slider 202, so that the emission surface of the corresponding laser 204 faces the flexure mating surface 202a of the slider 202. Typically, openings are formed in both the flexure 308 (shown partially in dashed lines to clarify the load beam assembly in context) and the load beam 310, and the laser module passes through these openings to couple with the slider 202. Longitudinal side rails 312 are typically created on each lateral side of the load beam 310 by bending the sides of the load beam 310.

[0013] 4A is a top view of a known slider-flexure assembly. The assembly 400 includes a head slider 402 (or simply "slider 402," shown here in dashed lines for clarity) adhesively bonded to a suspension flexure 404 ("flexure 404") via adhesive 403. The flexure 404 includes an extension structure 404a (sometimes called a stud, "standoff feature," or "standoff 404a") that extends from a major planar structure or body of the flexure 404 (e.g., from a tongue portion of the flexure 404) and to which a suspension surface of the slider 402 is adhered. Conventionally, certain visual identification and / or targeting features are established on the HAMR mounting surface of the slider 402 to facilitate the use of machine vision (and / or computer vision) techniques for the assembly of the HAMR slider, such as for mounting a CoSA (see, e.g., laser 204 and submount 206 in FIG. 2) on the slider 402 surface. Because the native surface of the slider 402 is very shiny, typically because it is constructed from aluminum-titanium-carbide (AlTiC), an anti-reflective coating (anti-reflective reflective coating) is applied to at least partially assist machines in "seeing" or reading such features. A coating (ARC) 406 is applied to a portion of the surface of the slider 402. Thus, the manufacturing features are established on the surface of the ARC 406, and not on the surface of the slider 402. However, one challenge or disadvantage with applying an ARC 406 having the illustrated footprint and within manufacturing tolerances is that the ARC 406 may not intersect with the standoff 404a in an undesirable manner, and therefore the slider 402 may not be attached precisely, stably, or consistently enough. For example, note that the outer edge of the ARC 406 may or may not completely and stably bond with the standoff 404a structure at all points, and the edge of the ARC 406 may intersect with the adhesive 403 in an undesirable manner. For example, the slider 402 may be attached at an undesirable angle, rather than being fully parallel to the flexure 404.As a result, the clearance between the slider 402 and the flexure 404 may be insufficient to prevent / prevent the slider 402 from undesirably contacting the flexure 404, which may inhibit the dual actuator system (e.g., a PZT microactuator) from operating accurately and effectively without being hindered by slider-flexure contact.

[0014] Enhanced slider coating improvements 4B is a top view of a reinforced slider-flexure assembly according to one embodiment. The assembly 450 includes a head slider 402 (shown here in dashed lines for clarity) adhesively bonded to a suspension flexure 404 ("flexure 404") via adhesive 403. The slider 402 has a slider body with a leading edge (LE) surface, a suspension surface / surface facing the flexure 404, and a recording medium surface / surface opposite the suspension surface, and contains a read-write transducer (see, e.g., magnetic read-write head 110a of FIG. 1) at or near a trailing edge (TE) surface opposite the LE surface of the slider 402 body. Again, the flexure 404 includes an extension structure 404a (sometimes referred to as a "standoff 404a") that extends from a major planar structure or body of the flexure 404 (e.g., from a tongue of the flexure 404) and to which a suspension surface of the slider 402 is adhered. According to one embodiment, an anti-reflective coating (ARC) 456 is applied to an extended and larger portion of the surface of the slider 402 than in the assembly 400 of FIG. 4A. Thus, the slider 402 is coated with an ARC 456 that extends at least to at least the furthest portion in the LE direction of the standoff 404a of the flexure 404. According to one embodiment, as shown, the ARC 456 extends substantially from the TE surface of the slider 402 along the suspension surface, terminating just beyond the standoff 404a of the flexure 404. According to one embodiment, the ARC 456 is configured to be in physical contact with a majority of the mating surface of the standoff 404a of the flexure 404. According to one embodiment, the ARC 456 is configured to be in physical contact with the entire adhesive 403 wetting area of ​​the flexure 404. Stated another way, the adhesive 403 attaches the slider 402 to the flexure 404 such that the adhesive 403 is positioned to contact at least a portion of the ARC 456 across its entire footprint.It should be noted that the coating material referred to as antireflective coating (ARC) 456 may vary from implementation to implementation, and thus slider coating materials other than antireflective materials (e.g., typically some composition such as silicon oxide, or tantalum oxide, or platinum, or titanium, etc.) may be applied to slider 402 for the purposes described herein.

[0015] One anticipated benefit of extending the footprint of ARC456 as described and illustrated is increased adhesive (e.g., shear) strength, at least in part, because the surface roughness of ARC456 (e.g., Ra=0.974 nm for silicon oxide) is greater than the surface roughness of the AlTiC underlying the slider 402 body (e.g., Ra=0.440 nm). FIG. 5 is a side view of a slider-adhesive interface comparing an uncoated smooth surface with a coated rough surface, according to one embodiment. As exemplified by the application of ARC456, the rough surface effectively provides a larger surface area for adhesive 403 for adhesion purposes than the uncoated smooth surface of the AlTiC slider 402. A study of the shear strength of the adhesive bond between adhesive 403 and the rough surface of ARC456 showed an increase of about 55% compared to the adhesive bond between adhesive 403 and the smooth AlTiC surface of slider 402.

[0016] Figure 6A is a top view showing critical areas of clearance for a slider-flexure assembly, and Figure 6B is a side view showing areas of clearance for a slider-flexure assembly, both according to one embodiment. Assembly 600 is shown comprising a slider 402 (shown here in dashed lines for clarity) coupled to a flexure 404 having extension structures or standoffs 404a extending from a major planar body 404m of the flexure 404 to form mounting support for the slider 402. These components are identical or similar in function to the similar components of Figure 4B.

[0017] For resistance (friction) free dual stage actuator (e.g., PZT microactuator) stroke rotation, a clearance (c) is generally desired between the flexure 404 and the LE half of the slider 402. The illustrated region corresponding to the footprint of the slider 402 is considered the region of critical clearance, whereby sufficient clearance preferably always exists according to a given design configuration. For example, a typical design clearance between a slider 402 and a corresponding flexure 404 is only about 5 μm (micrometers, or microns) under ideal conditions. However, such clearance is highly dependent on the height of the localized flexure cover overlay (or "coverlay") features and the parallelism control of the slider attachment joint (e.g., between the slider and the flexure). Furthermore, in the context of HAMR sliders, HAMR sliders are relatively long (e.g., in the TE-LE direction, in some cases about 50% longer than conventional sliders) and have a very limited bonding area, which increases the risk of slider-flexure contact (e.g., parallelism control margins are about 1.5 times tighter than conventional non-HAMR sliders). Thus, again, even a slight tilt of the slider bonding attachment toward the flexure LE can result in contact and dynamic performance anomalies / instability issues. Furthermore, the presence of the HAMR CoSA further limits the slider attachment (e.g., adhesion) area.

[0018] FIG. 6C is a side view showing an ideal slider mount in the known slider-flexure assembly of FIG. 4A, and FIG. 6D is a side view showing an unstable slider mount in the known slider-flexure assembly of FIG. 4A. In this case, the ARC 406 extends only about 30% along the length of the slider 402 from the TE, and therefore does not completely cover the location area of ​​the standoff 404a. Thus, as shown generally, there is very limited overlap between the ARC 406 and the standoff 404a to achieve stable slider mount parallelism control. Thus, the mount of the slider 402 may tilt as shown in FIG. 6D, which may result in undesirable contact with the flexure 404.

[0019] Figure 7 is a side view showing a stable slider attachment for the enhanced slider-flexure assembly of Figure 4B, according to one embodiment. In contrast to the ARC 406 of Figures 6C and 6D, according to one embodiment, an enhanced ARC application such as ARC 456 coating a first portion of the suspension surface of the slider 402 that extends to at least the furthest portion in the LE direction (i.e., toward or toward the LE plane) of the standoff 404a of the flexure 404 allows for a more stable attachment and more controlled joint parallelism. According to a related embodiment, the ARC 456 extends substantially from the TE plane onto the suspension surface of the slider 402, terminating just beyond the standoff 404a. In either case, a second portion of the suspension surface of the slider 402 body beyond the standoff 404a structure of the flexure 404 (in a direction toward the LE plane) is not coated with ARC 456 such that the second portion is at a greater distance from the major planar body of the flexure 404 (e.g., see major planar body 404m in FIG. 6B) than the first portion. In other words, the TE portion of the slider 402 corresponding to the TE portion of the suspension surface is thicker than the LE portion of the slider 402 corresponding to the LE portion of the suspension surface due to the additional thickness corresponding to the applied ARC 456. Thus, undesired contact between the slider 402 and the flexure 404, such as during a microactuation operation, can be avoided.

[0020] Method for manufacturing a head gimbal assembly for a hard disk drive 8 is a flow diagram illustrating a method for manufacturing a head gimbal assembly of a hard disk drive according to one embodiment. A head gimbal assembly (HGA) manufactured according to the method of FIG. 8 is designed and configured for mounting in a hard disk drive (HDD) (see, for example, FIG. 1). For context, each individual head slider has a slider body having what is referred to herein as a suspension surface, a recording medium surface opposite the suspension surface, and a leading edge (LE) surface connecting the suspension surface and the recording medium surface, and contains a read-write transducer at or near a trailing edge (TE) surface opposite the LE surface and connecting the suspension surface and the recording medium surface.

[0021] In block 802, a first portion of the suspension surface of the head slider is coated with an anti-reflective coating (ARC). For example, a first portion (see, for example, FIG. 7) of the surface (i.e., suspension surface) of the slider 402 (FIGS. 4B, 6A-6B, 7) facing the flexure is coated with an ARC 456 (FIGS. 4B, 7), for example, starting at or near the TE surface.

[0022] In block 804, the head slider is bonded to a suspension assembly including a flexure having a standoff structure to which the suspension surface of the slider is bonded, and the ARC is positioned to extend to at least the furthest portion of the standoff structure of the flexure in a direction toward the LE surface. For example, the head slider 402 is bonded to a suspension assembly including a flexure 404 (FIGS. 4B, 6A-6B, 7) having a standoff 404a (FIGS. 4B, 6A-6B, 7) to which the suspension surface of the slider 402 is bonded, and the ARC 456 is positioned to extend to at least the furthest portion of the standoff 404a of the flexure 404 in a direction toward the LE surface, for example, the ARC 456 covers the entire portion of the slider 402 that is in physical contact with the standoff 404a. Thus, using such a configuration and positioning of the ARC 456 on the suspension surface of the slider 402 allows for (i) better bonding between the slider 402 and the flexure 404 due to the increased surface roughness of the ARC 456 compared to the AlTiC slider body, (ii) better stabilization of the slider 402 by perfectly aligning the ARC 456 with the standoff 404a by avoiding teetering at the contact point, referred to elsewhere herein as (better) bond parallelism control, and (iii) the additional thickness of the ARC 456 at the standoff 404a allows or provides more clearance and therefore better rotation of the slider 402 about the gimbal dimple during micro-actuation.

[0023] According to one embodiment, coating the first portion of the suspension surface (block 802) includes coating the first portion substantially from the TE plane to an end location immediately adjacent where the standoff 404a of the flexure 404 is located. Additionally, according to one embodiment, coating the first portion includes not coating a second portion of the suspension surface of the slider 404 (see, e.g., FIG. 7) beyond the end location of the first portion toward the LE plane, such that the second portion is at a greater distance from the major planar body 404m (FIG. 6B) of the flexure 404 than the first portion.

[0024] Illustrative physical description of the operating context The embodiments may be used in the context of a digital data storage device (DSD), such as a hard disk drive (HDD). Thus, according to an embodiment, a plan view showing a conventional HDD 100 is shown in FIG. 1 to help describe how a conventional HDD typically operates.

[0025] FIG. 1 shows a functional arrangement of components of a HDD 100, including a slider 110b that includes a magnetic read-write head 110a. Collectively, the slider 110b and the head 110a may be referred to as a head slider. The HDD 100 includes at least one head gimbal assembly (HGA) 110 that includes the head slider, a lead suspension 110c that is typically attached to the head slider via a flexure, and a load beam 110d that is attached to the lead suspension 110c. The HDD 100 also includes at least one recording medium 120 that is rotatably mounted on a spindle 124, and a drive motor (not visible) that is attached to the spindle 124 to rotate the medium 120. The read-write head 110a, which may also be referred to as a transducer, includes a write element and a read element for writing and reading information stored on the medium 120 of the HDD 100, respectively. The medium 120 or multiple disk media may be secured to a spindle 124 with a disk clamp 128 .

[0026] The HDD 100 further includes an arm 132 mounted to the HGA 110, a carriage 134, and a voice coil motor (VCM) including an armature 136 including a voice coil 140 mounted to the carriage 134, and a stator 144 including a voice coil magnet (not shown). The VCM armature 136 is attached to the carriage 134 and is configured to move the arm 132 and HGA 110 to access portions of the media 120, all collectively mounted on a pivot shaft 148 with an intervening pivot bearing assembly 152. In a HDD with multiple disks, the carriage 134 may be referred to as an "E-block" or comb because the carriage is arranged to carry an array of interlocking arms that give the carriage the appearance of a comb.

[0027] An assembly comprising a head gimbal assembly (e.g., HGA 110), including a flexure to which a head slider is coupled, an actuator arm (e.g., arm 132) and / or a load beam to which the flexure is coupled, and an actuator (e.g., VCM) to which the actuator arm is coupled, may be collectively referred to as a head stack assembly (HSA). However, an HSA may include more or less components than those listed. For example, an HSA may refer to an assembly that further includes electrical interconnect components. In general, an HSA is an assembly configured to move a head slider to access portions of the medium 120 for read and write operations.

[0028] With further reference to FIG. 1 , electrical signals including write signals to and read signals from head 110a (e.g., current to the voice coil 140 of the VCM) are transmitted by a flexible cable assembly (FCA) 156 (or “flex cable,” or “flexible printed circuit” (FPC)). The interconnect between flex cable 156 and head 110a may include an arm-electronics (AE) module 160, which may have on-board preamplifiers for the read signal, as well as other read channel and write channel electronics. The AE module 160 may be mounted to the carriage 134 as shown. The flex cable 156 may be coupled to an electrical connector block 164, which in some configurations provides electrical communication through an electrical feedthrough provided by an HDD enclosure 168. The HDD housing 168 (or “enclosure base”, or “base plate” or simply “base”), together with the HDD cover, provides a semi-sealed (or, in some configurations, hermetically sealed) protective enclosure for the information storage components of the HDD 100.

[0029] A disk controller including a digital-signal processor (DSP) and other electronic components including servo electronics provide electrical signals to the drive motor, the voice coil 140 of the VCM, and the head 110a of the HGA 110. The electrical signals provided to the drive motor enable the drive motor to rotate providing a torque to the spindle 124, which is then transferred to the medium 120 attached to the spindle 124. As a result, the medium 120 rotates in a direction 172. The rotating medium 120 forms a cushion of air that acts as an air-bearing on which the air-bearing surface (ABS) of the slider 110b rides so that the slider 110b flies above the surface of the medium 120 without contacting the thin magnetic recording layer on which the information is recorded. Similarly, in HDDs where a lighter-than-air gas such as helium is utilized as a non-limiting example, the rotating medium 120 creates a cushion of gas that acts as a gas or fluid bearing on which the slider 110b rides.

[0030] An electrical signal provided to the voice coil 140 of the VCM enables the head 110a of the HGA 110 to access the track 176 on which information is to be recorded. Thus, the armature 136 of the VCM swings through an arc 180 to enable the head 110a of the HGA 110 to access various tracks on the medium 120. Information is stored on the medium 120 in a number of radially nested tracks arranged in sectors on the medium 120, such as sector 184. Correspondingly, each track is made up of a number of sectorized track portions (or "track sectors"), such as sectorized track portion 188. Each sectorized track portion 188 may include the recorded information and a header that includes error correction code information and a servo burst signal pattern, such as an ABCD servo burst signal pattern, which is information identifying the track 176. When accessing track 176, a read element of head 110a of HGA 110 reads a servo burst signal pattern that provides a position-error-signal (PES) to the servo electronics, which enables head 110a to follow track 176 by controlling an electrical signal provided to the voice coil 140 of the VCM. Upon locating track 176 and identifying a particular sectored track portion 188, head 110a reads information from track 176 or writes information to track 176 in response to instructions received by a disk controller from an external agent, e.g., a microprocessor of a computer system.

[0031] The electronic architecture of an HDD includes numerous electronic components, such as a hard disk controller ("HDC"), an interface controller, an arm electronics module, a data channel, a motor driver, a servo processor, a buffer memory, etc., each performing its respective function for the operation of the HDD. Two or more of such components may be combined on a single integrated circuit board, referred to as a "system on a chip" ("SOC"). Some, but not all, of such electronic components are typically located on a printed circuit board that is coupled to the bottom side of the HDD, such as in the HDD housing 168.

[0032] References herein to hard disk drives, such as HDD 100 shown and described with reference to FIG. 1, may encompass information storage devices that may be referred to as "hybrid drives." A hybrid drive generally refers to a storage device that has the functionality of both a traditional HDD (see, e.g., HDD 100) combined with a solid-state storage device (SSD) that uses non-volatile memory such as electrically erasable and programmable flash or other solid-state (e.g., integrated circuit) memory. Because the operation, management, and control of different types of storage media are typically different, the solid-state portion of the hybrid drive may include its own corresponding controller functionality, or the controller functionality may be integrated into a single controller along with the HDD functionality. A hybrid drive may be designed and configured to operate and utilize the solid-state portion in several ways, such as by using the solid-state memory as a cache memory, as a non-limiting example, to store frequently accessed data, to store I / O intensive data, and the like. Additionally, a hybrid drive may be designed and configured essentially as two storage devices in a single enclosure, i.e., a traditional HDD and an SSD, with either one or multiple interfaces for host connection.

[0033] Extensions and Alternatives In the foregoing description, the embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Accordingly, various modifications and changes may be made without departing from the broader spirit and scope of the embodiments. Thus, the sole and exclusive reference of what is, and what the applicants intend to be, the invention is the set of claims originating from this application, in the particular form in which such claims originate, including any subsequent amendments. The definitions expressly set forth herein for the terms contained in such claims shall govern the meaning of the terms as used in the claims. Hence, any limitations, elements, characteristics, features, advantages or attributes not expressly recited in the claims should in no way limit the scope of such claims. Hereby, the specification and drawings are to be regarded in an illustrative and not restrictive sense.

[0034] Additionally, certain process steps may be described herein in a particular order, and alphabetic and alphanumeric symbols may be used to identify particular steps. Unless otherwise specified herein, embodiments are not necessarily limited to any particular order of performing such steps. In particular, symbols are used merely for convenient identification of steps, and are not intended to specify or require a particular order of performing such steps. The following items are elements of the claims as originally filed: (1) a head slider having a slider body having a leading edge (LE) surface, a suspension surface, and a recording medium surface opposite the suspension surface, the slider housing a read-write transducer at or near a trailing edge (TE) surface of the slider body opposite the LE surface; a suspension assembly including a flexure having an extension structure extending from a major planar body of the flexure to which the suspension surface of the slider is bonded; an assembly, wherein a first portion of the suspension surface of the slider body is coated with an anti-reflective coating (ARC) that extends to at least a furthest portion, in a direction of the LE plane, of the extension structure of the flexure. (2) Item 2. The assembly of item 1, wherein the ARC extends substantially from the TE surface and terminates just beyond the extended structure of the flexure. (3) 3. The assembly of claim 2, wherein a second portion of the suspension surface of the slider body beyond the extended structure of the flexure toward the LE plane is not coated with the ARC such that the second portion is at a greater distance from the major planar body of the flexure than the first portion. (4) Item 2. The assembly of item 1, further comprising an adhesive that attaches the head slider to the extension structure of the flexure and contacts the entirety of the adhesive with a portion of the first portion of the suspension surface of the slider body. (5) Item 5. The assembly of item 4, wherein the ARC has a surface roughness that is greater than a surface roughness of the slider body. (6) Item 5. The assembly of item 4, wherein the ARC is configured to be in physical contact with a majority of a mating surface of the extension structure of the flexure. (7) Item 1, the assembly of item 1 further comprising a thermally assisted magnetic recording (HAMR) chip-on-submount assembly (COSA) comprising a submount to which the laser is coupled. (8) Item 1. A hard disk drive comprising the assembly according to item 1. (9) A head slider for a hard disk drive, a slider body having a leading edge (LE) surface, a suspension surface, and a recording medium surface opposite the suspension surface, the slider housing a read-write transducer at or near a trailing edge (TE) surface of the slider body opposite the LE surface; an anti-reflective coating (ARC) covering a TE portion of the suspension surface of the slider body and extending at least to an entire attachment portion of the suspension surface configured to attach the slider to a suspension assembly. (10) 10. The head slider of claim 9, wherein the ARC extends from the TE surface just beyond the mounting portion. (11) The slider body includes: 10. The head slider of claim 9, further comprising a LE portion of the suspension surface that is positioned beyond the mounting portion and is not coated with the ARC such that a TE portion of the slider corresponding to the TE portion of the suspension surface is thicker than a LE portion of the slider corresponding to the LE portion of the suspension surface. (12) 10. The head slider of claim 9, wherein the ARC is constructed from a material having a surface roughness greater than a surface roughness of the slider body. (13) 10. The head slider of claim 9, further comprising a heat-assisted magnetic recording (HAMR) chip-on-submount assembly (COSA) comprising a submount having a laser bonded thereto. (14) Item 14. A hard disk drive comprising the head slider according to item 13. (15) 1. A method of manufacturing a hard disk drive (HDD) head gimbal assembly (HGA), the method comprising: coating a first portion of a suspension surface of a head slider having a slider body having a leading edge (LE) surface, a suspension surface, and a recording medium surface opposite the suspension surface with an anti-reflective coating (ARC); and bonding the head slider to a suspension assembly including a flexure having a standoff structure to which the suspension surface of the slider is bonded; The method, wherein the ARC is positioned to extend to at least a furthest portion of the standoff structure of the flexure in a direction toward the LE surface. (16) Item 16. The method of item 15, wherein coating the first portion includes coating the first portion from the TE surface to an end location of the flexure immediately adjacent where the standoff structure is located. (17) Item 17. The method of item 16, wherein coating the first portion includes not coating a second portion of the suspension surface of the slider body beyond the end location of the first portion in the direction of the LE plane, whereby the second portion is at a greater distance from the flexure major planar body than the first portion. (18) Adhering the head slider includes applying an adhesive to a portion of the first portion of the suspension surface; Item 16. The method of item 15, wherein the ARC has a surface roughness that is greater than a surface roughness of the slider body. (19) Item 15. A hard disk drive manufactured according to the method of claim 15. HGA. (20) a head slider having a slider body with a suspension surface and a recording medium surface opposing the suspension surface, the slider housing a read-write transducer; an anti-reflective coating (ARC) covering a portion of the suspension surface of the slider body; a suspension assembly including a flexure; an adhesive for attaching the head slider to the flexure, the adhesive positioned such that the entire adhesive contacts at least a portion of the ARC. (21) 21. The assembly of claim 20, wherein the ARC has a surface roughness that is greater than a surface roughness of the slider body.

Claims

1. a head slider having a slider body having a leading edge (LE) surface, a suspension surface, and a recording medium surface opposite the suspension surface, the head slider housing a read-write transducer at or near a trailing edge (TE) surface of the slider body opposite the LE surface; a suspension assembly including a flexure having an extension structure extending from a major planar body of the flexure to which the suspension surface of the head slider is bonded; a first portion of the suspension surface of the slider body is coated with an anti-reflective coating (ARC) that extends to at least a furthest portion of the extension structure of the flexure in a direction of the LE plane; the ARC extends substantially from the TE plane and terminates just beyond the extended structure of the flexure; assembly.

2. 2. The assembly of claim 1, wherein a second portion of the suspension surface of the slider body beyond the extended structure of the flexure toward the LE plane is not coated with the ARC such that the second portion is at a greater distance from the major planar body of the flexure than the first portion.

3. 2. The assembly of claim 1, further comprising an adhesive attaching the head slider to the extension structure of the flexure and entirely in contact with a portion of the first portion of the suspension surface of the slider body.

4. The assembly of claim 3 , wherein the ARC has a surface roughness that is greater than a surface roughness of the slider body.

5. The assembly of claim 3 , wherein the ARC is configured to be in physical contact with a majority of a mating surface of the extension structure of the flexure.

6. 10. The assembly of claim 1, further comprising a thermally assisted magnetic recording (HAMR) chip-on-submount assembly (COSA) comprising a submount to which the laser is coupled.

7. A hard disk drive comprising the assembly of claim 1.

8. A head slider for a hard disk drive, a slider body having a leading edge (LE) surface, a suspension surface, and a recording medium surface opposite the suspension surface, the head slider housing a read-write transducer at or near a trailing edge (TE) surface of the slider body opposite the LE surface; an anti-reflective coating (ARC) covering a TE portion of the suspension surface of the slider body and extending at least across an attachment portion of the suspension surface configured to attach the head slider to a suspension assembly; The slider body includes: the TE portion of the head slider corresponding to the TE portion of the suspension surface is positioned beyond the attachment portion such that the LE portion of the head slider corresponding to the TE portion of the suspension surface is thicker than the LE portion of the head slider corresponding to the LE portion of the suspension surface, and the LE portion of the suspension surface is not coated with the ARC. Head slider.

9. The head slider of claim 8 , wherein the ARC extends from the TE surface just beyond the mounting portion.

10. 9. The head slider of claim 8, wherein the ARC is constructed from a material having a surface roughness greater than a surface roughness of the slider body.

11. 10. The head slider of claim 8, further comprising a heat-assisted magnetic recording (HAMR) chip-on-submount assembly (COSA) comprising a submount having a laser bonded thereto.

12. A hard disk drive comprising the head slider according to claim 11.

13. 1. A method of manufacturing a hard disk drive (HDD) head gimbal assembly (HGA), the method comprising: coating a first portion of a suspension surface of a head slider having a slider body having a leading edge (LE) surface, a suspension surface, and a recording medium surface opposite the suspension surface with an anti-reflective coating (ARC); and bonding the head slider to a suspension assembly including a flexure having a standoff structure to which the suspension surface of the head slider is bonded; the ARC is positioned to extend to at least a furthest portion of the standoff structure of the flexure in a direction toward the LE surface; coating the first portion includes coating the first portion from the TE surface to an end location immediately adjacent where the standoff structure of the flexure is located. method.

14. 14. The method of claim 13, wherein coating the first portion includes not coating a second portion of the suspension surface of the slider body beyond the end location of the first portion in the direction of the LE plane, whereby the second portion is at a greater distance from a major planar body of the flexure than the first portion.

15. Adhering the head slider includes applying an adhesive to a portion of the first portion of the suspension surface; The method of claim 13 , wherein the ARC has a surface roughness that is greater than a surface roughness of the slider body.

16. 14. A HDD HGA manufactured according to the method of claim 13.

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