HK1154114B

HK1154114B - Head gimbal assembly having a radial rotary piezoelectric microactuator between a read head and a flexure tongue

Info

Publication number: HK1154114B
Application number: HK11108243.5A
Authority: HK
Inventors: N．C．艾米丽
Original assignee: 西部数据（弗里蒙特）公司
Priority date: 2009-12-21
Filing date: 2011-08-08
Publication date: 2016-03-24

Description

Head suspension assembly having radially rotating piezoelectric microactuator between read head and flexure tongue

Technical Field

The present invention relates generally to the field of information storage devices, and more particularly to a head suspension (gimbal) assembly for use in an information storage device and including a microactuator.

Background

In computers and other consumer electronic devices, information storage devices are used to retrieve and/or store data. Magnetic hard disk drives are an example of information storage devices that include one or more heads that can both read and write, but other information storage devices also include heads-sometimes including heads that cannot write. For convenience, all heads capable of reading are referred to herein as "read heads," regardless of other devices and functions that the read head may perform in addition (e.g., writing, fly height control, touchdown detection, lapping control, etc.).

In modern magnetic hard disk drives, each read head is a subcomponent of a Head Gimbal Assembly (HGA). The read head typically includes a slider and a read/write transducer. The read/write transducer typically includes a magnetoresistive read element (e.g., a so-called giant magnetoresistive read element or a tunneling magnetoresistive read element) and an inductive write structure including a pancake coil deposited using lithography and a head stack (yoke) structure having a pole tip (pole tip) facing the disk medium.

HGAs also typically include a suspension assembly having a laminated flexure to carry electrical signals to and from the read head. The read head is typically bonded to the tab member of the laminate flexure. The HGAs are sub-components of a Head Stack Assembly (HSA), which typically includes multiple HGAs, a rotational actuator, and a flexible cable. Multiple HGAs are connected to respective arms of the rotational actuator, and each of the laminated flexure components of the HGAs has a flexure tail that is electrically connected to a flex cable of the HSA.

Modern laminated flexure components typically include electrically conductive copper traces separated from a stainless steel support layer by a polyimide insulating layer so that signals from/to the head can reach the flex cable on the actuator body, each HGA flexure including a curved tail that extends along the actuator arm away from the head and ultimately connects to the flex cable adjacent the actuator body. That is, the flexure includes conductive traces that are electrically connected to a plurality of conductive bonding pads on the head and extend from a location adjacent the head to terminate at electrical connection points at the flexure tail.

The position of the HSA relative to the rotating disk in a disk drive, and hence the position of the read head relative to the data tracks on the disk, is actively controlled by a rotary actuator, which is typically driven by a Voice Coil Motor (VCM). Specifically, the current flowing through the VCM coil applies a torque to the rotary actuator so that the read head can seek and track a desired data track on the rotating disk.

However, the industry trend toward increasing areal data densities has necessitated a significant reduction in the spacing between data tracks on the disk. At the same time, disk drive performance requirements, particularly with respect to the time required to access desired data, do not allow the rotational speed of the disk to be reduced. In fact, for many disk drive applications, the rotational speed has increased significantly. The result of these trends is: there is a need to increase the bandwidth of servo control of read head position relative to data tracks on rotating disks.

To increase the disk servo bandwidth, one solution that has been proposed in the art is dual-order braking. According to the two-step brake concept, the VCM-driven rotary brake is used as a coarse brake (for large adjustments of HAS position relative to the disk), while a so-called "micro-brake" with a larger bandwidth but less stroke is used as a fine brake (for smaller adjustments in read head position). Several microactuator designs and servo control schemes have been proposed in the art for the purpose of dual-stage braking in disk drive applications.

However, adding one or more micro-actuators in a disk drive can be expensive and cumbersome. For example, the additional components of the microactuator add to the cost of the disk drive, as do the additional manufacturing steps required to produce and assemble the disk drive including the microactuator. Furthermore, the increased complexity of the braking system may reduce disk drive manufacturing yield and may increase the failure rate of the disk drive during operation in the field. The increased development time for successful implementation of a complex two-stage braking system delays product deployment, which can result in significant opportunity costs to disk drive manufacturers.

Accordingly, there is a need in the art for a microactuator design that is beneficial for dual-step actuation in disk drive applications and has acceptable cost and manufacturability for profitable mass production.

Disclosure of Invention

A novel Head Gimbal Assembly (HGA) includes a read head, a load beam, and a piezoelectric microactuator. The read head has an air bearing surface and an opposing top surface. A flexure is coupled to the load beam and includes a tab having a tab major surface. The piezoelectric microactuator has a first side and an opposing second side. The first side faces the tongue major surface and is generally parallel thereto. The first side includes a plurality of anchor regions extending radially from a center point. Each of the plurality of anchor regions is coupled to a tab. The first side further includes a first plurality of unbonded areas that are not bonded to the tab. Each of the first plurality of non-binding regions is located between two of the plurality of anchor regions. The second side includes a plurality of connection regions extending radially from the center point. Each of the plurality of link regions is bonded to a top surface of the read head. The second side also includes a second plurality of unbonded areas that are not bonded to the top surface of the read head. Each of the second plurality of non-bonded regions is located between two of the plurality of connected regions. Each of the plurality of connection regions is angularly spaced between two of the plurality of anchor regions.

Drawings

FIG. 1 is a top view of a disk drive that can include an embodiment of the present invention.

FIG. 2 is a bottom view of a Head Gimbal Assembly (HGA) that can include an embodiment of the present invention.

FIG. 3 is a top view of a read head and piezoelectric microactuator according to an embodiment of the present invention.

FIG. 4 depicts a side view schematic of the operation of a piezoelectric microactuator according to an embodiment of the present invention.

FIG. 5 depicts an enlarged side view of one of the suspended regions of a piezoelectric microactuator according to an embodiment of the present invention.

Fig. 6 shows the embodiment of fig. 3 in operation, with a 500-fold magnification variation.

FIG. 7 is a top view of a read head and piezoelectric microactuator according to another embodiment of the present invention.

FIG. 8 is a top view of a read head and piezoelectric microactuator according to another embodiment of the present invention.

Detailed Description

FIG. 1 is a top view of a disk drive 100 that can include an embodiment of the present invention. The disk drive 100 includes a disk drive base 102 and an annular magnetic disk 104. The disk drive 100 also includes a spindle 106 rotatably mounted on the disk drive base 102 for rotating the disk 104. The rotation of the magnetic disks 104 generates an airflow through the recirculation filter 108. In some embodiments, the disk drive 100 may have only a single disk 104, or alternatively, two or more disks.

The disk drive 100 also includes a rotational actuator 110 that is rotatably mounted on the disk drive base 102. The rotational brake 110 includes a brake arm 114 that supports a Head Gimbal Assembly (HGA) 200. The voice coil motor 112 rotates the actuator 110 through a limited angular range so that the HGA 200 may be positioned as desired relative to one or more tracks of information on the disk 104. Preferably, the disk drive 100 will include one HGA 200 for each disk surface, but a smaller number of disk drives using fewer HGAs is also contemplated. In the non-operational condition, the HGA may be parked on the ramp 120 to avoid contact with the disk 104 when the disk is not rotating. Electronic signals from/to the HGA 200 are carried through the flex cable bracket 116 to other drive electronics.

FIG. 2 is a bottom view of an HGA 200 that can include an embodiment of the present invention. The HGA 200 includes a load beam 202 and a read head 210 for reading data from and writing data to a magnetic disk (e.g., disk 104). The read head 210 includes a slider substrate having an air bearing surface (to which the marks 210 are directed) and an opposing top surface (not visible in FIG. 2). The slider substrate preferably comprises AlTiC, but other ceramics or silicon may be used. The slider substrate of the read head 210 also includes a trailing surface 212 that includes a read/write transducer (too small to be physically shown in FIG. 2, but disposed on the trailing surface 212). In certain embodiments, the read/write transducer is preferably an inductive magnetic write transducer in combination with a magnetoresistive read transducer. The purpose of the load beam 202 is to provide vertical compliance for the read head 210 to conform to vertical undulations of the surface of a disk (e.g., disk 104 of FIG. 1) as the disk rotates, and to preload the air bearing surface of the read head 210 against the disk surface with a preload force commonly referred to as a "head stack load".

The HGA 200 also includes a laminated flexure 204 coupled to the load beam 202. The magnetic head 210 is connected to the tab of the laminated flexure 204. Since the read head 210 typically obscures the tab, the tab is not easily visible in the view of FIG. 2. A first purpose of the laminated flexure 204 is to provide compliance for the head 210 to follow the longitudinal and lateral angular undulations of the disk surface as the disk (e.g., disk 104) rotates, while limiting relative motion between the read head 210 and the load beam 202 in a lateral direction about the offset axis. A second purpose of the laminated flexure 204 is to provide multiple electrical paths to facilitate signal transmission to/from the read head 210. For a second purpose, the laminated flexure 204 includes a plurality of conductive traces 218 defined in a conductive (e.g., copper) sub-layer of the laminated flexure 204. The conductive traces 218 are separated from the support layer (e.g., stainless steel) by an insulating layer (e.g., polyimide).

FIG. 3 is a top view of a read head 300 and a piezoelectric microactuator 310 according to an embodiment of the present invention. Read head 300 has an air bearing surface 302 and an opposing top surface 304. Read head 300 also has a trailing surface 306 that includes a read transducer (not shown) and may also include a write transducer or the like. The piezoelectric microactuator 310 has a first side 312 and an opposing second side (not visible in the view of FIG. 3 because it is on the bottom side of the piezoelectric microactuator 310 facing the top surface 304 of the read head 300). The piezoelectric microactuator 310 preferably has a maximum thickness, measured approximately perpendicular to the tab major surface, in the range of 5 to 50 microns.

In the embodiment of FIG. 3, the first side 312 of the piezoelectric microactuator 310 faces and is generally parallel to a major surface of the flexure tongue (not shown in FIG. 3). The first side 312 of the piezoelectric microactuator 310 includes four anchor regions 320 that extend radially from a center point 322. Each of the anchor regions 320 is combined with a flexure tongue, which qualifies it as an "anchor" region. The first side 312 of the piezoelectric microactuator 310 also includes four unbonded areas (areas between anchor areas 320) that are not bonded to the flexure tongue. Each of the unbonded regions is located between two anchor regions 320.

In the embodiment of fig. 3, an aperture 324 extends through the piezoelectric microactuator, and the aperture 324 includes the center point 322. The holes 324 preferably have a diameter in the range of 0.1mm to 0.5. mm. A hole having a diameter within this range of values may advantageously eliminate portions of the piezoelectric microactuator 310 that might otherwise experience excessive shear stress in the event of relative vertical motion of the read head 300 (e.g., due to vibration during operation). In some cases, such high shear stresses may lead to material fracture, cracking, de-coring of the piezoelectric layer, and/or cyclic fatigue.

Each of the plurality of anchor regions 320 is preferably an anchor plateau (anchor plateau) that projects from the first side 312 in a direction approximately perpendicular to the tongue major surface. In such embodiments, each of the unbonded areas (between anchor areas 320) is recessed from the flexure tongue major surface relative to the adjacent anchor plateau. For example, each of the anchor plateaus can protrude at least 1 to 20 micrometers from the first side 312 (in a direction approximately perpendicular to the tongue major surface) relative to the unbonded area therebetween. The anchor plateau preferably has a laminated structure, for example, including one or more malleable metal layers and one or more insulating layers (e.g., an insulating ceramic). For example, the anchor plateau may comprise alumina or silica (e.g., SiO) adjacent to a piezoelectric material₂) Layers, e.g. having one on top thereofOr more than one patterned gold layer for bonding to the suspension tongue and carrying signals from the laminated flexure. The alumina or silica layer(s) may include one or more vias for electrical connection to the conductive layer of the laminated flexure in the suspension tongue region.

Alternatively, however, the anchor regions 320 may be formed by a distribution of adhesive only, rather than any actual plateaus in the piezoelectric microactuator 310. Alternatively, a plurality of recesses may be etched into the flexure tongue to distinguish the anchor regions 320 and the unbonded regions therebetween.

The second side (bottom of the view of fig. 3) of the piezoelectric microactuator 310 includes a plurality of connecting regions 340 that extend radially from the center point 322. These connection regions 340 are shown in phantom because they would not normally be visible from the perspective of fig. 3 (since they would protrude downwardly from the bottom surface of the piezoelectric microactuator 310 in fig. 3). Each of the plurality of link regions 340 is bonded to the top surface 304 of the read head 300. Four unbonded areas that are not bonded to the top surface of the read head are located on the second side of the piezoelectric microactuator 310 between each pair of the plurality of link areas 340. It should be noted that each of the plurality of connection regions 340 is angularly spaced between two of the plurality of anchor regions 320. Preferably, in the embodiment of fig. 3, each of the connection regions 340 is angularly spaced between two of the plurality of anchor regions 320 at an average angular spacing of no greater than 45 °. Such inequality is preferred for embodiments that include at least four anchor regions 320 and at least four connecting regions 340.

Each of the plurality of land areas 340 is preferably a land that protrudes from the second side of the piezoelectric microactuator 310 in a direction that is approximately perpendicular to the top surface 304 of the read head 300. In such an embodiment, each of the unbonded areas (between the connection areas 340) is recessed from the top surface 304 of the read head 300 relative to adjacent connection plateaus. For example, each of the connecting plateaus may be second-side (at approximately perpendicular to the top surface 304 of the read head 300) with respect to the unbonded areas therebetweenOf) at least 1 to 20 microns. The connection plateau preferably has a laminated structure, for example comprising a malleable metal layer and an insulating ceramic layer. For example, the connecting plateau may comprise a perforated alumina or silica (e.g., SiO) adjacent to the piezoelectric material₂) Layers, such as a layer of one or more patterned gold above it, are used to adhere to the top surface 304 of the read head 300 and to carry signals to/from the laminated flexure.

Alternatively, however, the connection region 340 may be formed by a distribution of adhesive only, rather than any actual plateau in the piezoelectric microactuator 310. Alternatively, a plurality of recesses may be etched into the top surface of the read head (e.g., during a bar level stage of slider fabrication) to distinguish the land areas 340 and the unbonded areas therebetween.

The embodiment shown in fig. 3 includes eight wedge-shaped free regions 330 that are common to both the unbonded regions on the first side 312 (between anchor regions 320) and the unbonded regions on the second side (at the bottom of the piezoelectric microactuator 310). The free regions 330 are not bonded to either the flexure tabs or the read head 300, which is why they are referred to as "free" regions. In some embodiments, the free region 330 is not only free of engagement with the flexure tongue and read head 300, but is also free of contact with the flexure tongue and read head 300. In such an embodiment, the free region 330 is also referred to as a "fly" region and its interfacial friction with the flexure tongue and/or the read head 300 is negligible.

Figure 4 depicts a side view schematic of the operation of a piezoelectric microactuator 400 according to an embodiment of the present invention. The read head 420 has an air bearing surface 422 and an opposing top surface 424. The piezoelectric microactuator 400 has a first side 402 and an opposing second side 404. The first side 402 faces and is generally parallel to the major surface 432 of the flexure tongue 430. The first side 402 includes a plurality of anchor regions 410. Each of the plurality of anchor regions 410 is coupled to a tab 430. The first side 402 also includes a first plurality of unbonded areas 412 that are not bonded to the tabs 430. Each of the first plurality of unbonded regions 412 is located between two of the plurality of anchor regions 410.

In the embodiment of FIG. 4, the second side 404 includes a plurality of link regions 414, each of which is bonded to a top surface 424 of the read head 420. The second side 404 also includes a non-bonded region 416 that is not bonded to the top surface 424 of the read head 420 and is located between two of the plurality of connection regions 414. Also, each of the plurality of connection regions 414 is spaced between two of the plurality of anchor regions 410.

In the embodiment of fig. 4, micro-actuation is accomplished by conventional application of an electric field to a piezoelectric micro-actuator 400. Preferably, the application of the electric field is limited to those regions that will cause the region to shrink on only one side of the connecting region 414. For example, FIG. 4 depicts micro-actuation of the read head 420 to the left by application of an electric field that is confined to the regions to the left of each of the link regions 414, causing lateral contraction (and concomitant thickening) of the piezoelectric micro-actuator 400 only in those regions. Specifically, the laterally constricted (and concomitant thickened) regions shown in FIG. 4 are disposed between each connecting region 414 and the anchor region 410 immediately to the left of that region. The lateral contraction in FIG. 4 causes the read head 420 to translate 450 to the left in the direction of arrow 452.

The reverse (right) micro-actuation of the read head 420 is preferably accomplished by the application of an electric field that is confined to those regions that will cause contraction of the regions to the right of each link region 414-causing lateral contraction (and concomitant thickening) of the piezoelectric micro-actuator 400 only in those regions. Specifically, a lateral contraction (and accompanying thickening) region for the right side micro-braking is disposed between each connection region 414 and the anchor region 410 immediately to its right. This right side micro-actuation will result in a right side translation of the read head 420 in the direction opposite arrow 452. These same principles as shown in fig. 4 may also be applied to clockwise and counterclockwise braking in a rotary micro-brake, as illustrated by the embodiments described below.

Simultaneous but distinct braking of the right-hand and left-hand regions is in principle possible for specific materials such as Pb [ Zr, Ti ]]O₃(which will be referred to as "PZT" hereinafter) is possible. For example, it is possible to apply an electric field to the PZT microactuator to cause the left region to laterally contract, while it is also possible to apply an electric field to cause the attendant right region to laterally expand. This differential braking may significantly increase the stroke of the brake, e.g., increase the distance of the left side translation 450. However, materials such as PZT typically suffer from a reduced piezoelectric response when an electric field is applied in a manner that results in elongation rather than contraction. Thus, while the desired microactuator travel is reduced by the application of an electric field, resulting in contraction to only one side of the link region (without the application of an electric field to cause expansion of the banded region), such limited application of an electric field may increase the useful life of the piezoelectric microactuator. This increase in service life may provide good evidence for any additional layers that may be necessary (no distinct braking) in the piezoelectric microactuator design to provide the appropriate travel.

Actuation of the piezoelectric microactuator may be accomplished by application of a voltage V across the actuator thickness t, which is accomplished by two conductive layers disposed on opposite sides. The electric field will be E ═ V/t. Preferably, the piezoelectric material (e.g., PZT) is polarized perpendicular to its planar structure. The conductive layers are thin relative to the piezoelectric layer and must remain electrically isolated from each other. In addition, the high voltage layer between the different suspended regions of the microactuator preferably remains electrically isolated so that voltages can be independently applied to them. Thus, a piezoelectric microactuator may require two different voltage connections and one ground connection.

Since the piezoelectric microactuator may include a suspended region constructed of thin films (t < 10 μm), such a region may be the structurally weakest point of the head suspension assembly. The hardness kappa of the piezoelectric layer approximately meets kappa ∈ (t/L)³It is therefore advantageous to maintain t as large as possible to maintain stiffness and structural integrity for a given length L. However, increasing the piezoelectric microactuatorMay weaken the applied electric field. Due to f_resonanceA ^ V ^ t and a stroke Δ L/V ^ t per unit volt^-1The stiffness of the piezoelectric microactuator can significantly affect the microactuator bandwidth, thus achieving an acceptable bandwidth and acceptable stroke has a contrasting design impact on the piezoelectric layer thickness. An advantageous compromise can be achieved by inserting an additional conductive layer through the thickness of the piezoelectric layer. Such a laminated piezoelectric layer with conductive and piezoelectric material sublayers can increase the stroke per volt while maintaining acceptable stiffness and bandwidth.

Fig. 5 depicts an enlarged side view of one of the suspended regions of a piezoelectric microactuator 500 according to an embodiment of the present invention. The piezoelectric microactuator 500 is shown as a laminated structure and the laminated structure includes a plurality of piezoelectric sublayers and a plurality of conductive layers. Each of the plurality of piezoelectric sublayers preferably has a thickness in the range of 0.1 to 2 microns. The conductive layer is shown as horizontal in fig. 5, which is approximately parallel to the flexure tongue major surface. Each of the plurality of piezoelectric sub-layers is preferably separated from another of the plurality of piezoelectric sub-layers by one of a plurality of conductive layers (e.g., platinum, gold, ruthenium oxide, indium tin oxide, etc.).

The piezoelectric microactuator 500 has a plurality of anchor regions, including anchor region 510, that are configured to be bonded to the major surfaces of the flexure tongue. The flexure tabs are not shown in fig. 5, but would be a horizontal layer located directly above and bonded to the anchor region 510. The unbonded area 512 that is not in contact with the flexure tongue is shown to the left of the anchor area 510 in FIG. 5. The unbonded area 512 shown in the enlarged view of fig. 5 is only one of the plurality of unbonded areas that are disposed between the pair of anchor areas.

In the embodiment of FIG. 5, the piezoelectric microactuator 500 also has a plurality of link regions, including link regions 513 and 514, which are bonded to the top surface of the read head 520. The non-bonded region 516 that is not in contact with the read head 520 is shown in FIG. 5 as being located between the link regions 513 and 514. The unbonded area 516 shown in the enlarged view of fig. 5 is only one of the plurality of unbonded areas disposed between the pair of attachment areas.

The piezoelectric microactuator 500 also includes a plurality of suspended regions. One of the float regions is shown in fig. 5 as a region of (and between) piezoelectric microactuator 500 that is common to the unbonded regions 512 and 516. It should be noted that this floating region does not contact the flexure tongue, nor does it contact the read head 520, which is why it is called a "floating" region.

Fig. 6 shows the embodiment of fig. 3 in operation, with a 500-fold magnification variation. It should be noted that every other of the eight free regions 330 is actuated to contract, so that each contracted free region contributes additional (rather than removal) torque to the read head 300. This results in a net rotation which in turn results in a translation 650 of the trailing surface 306. Since the read/write transducer is located on the trailing surface 306, the translation 650 of the trailing surface 306 can be used for dual-step braking in disk drive applications. When the other four free areas 330 are braked to contract, the opposite rotation and translation occurs.

The lateral contraction (per volt) of the levitation region can be described as:

ΔL/V＝d₃₁L/t

where L and t are the lateral dimension and thickness of the levitation region, respectively, and d₃₁Is the transverse piezoelectric constant (for thin film PZT, d)₃₁0.05 nm/V). Since the factor L/t appears in this equation, the lateral piezoelectric contraction may be affected by the design. However, the expansion per volt thickness is a material constant (e.g., Δ t/V ═ d)₃₃0.1 nm/V). In certain embodiments, the desired stroke per volt of the completed piezoelectric microactuator 310 is preferably in the range of 1-10nm/V, with a bandwidth in excess of 30 kHz.

From a cost perspective, it may be preferable to fabricate the piezoelectric microactuator 310 on a wafer using conventional wafer processing methods along with many other piezoelectric microactuators. For example, the suspension or release of the thin film may be first by depositionAnd patterning the sacrificial material. Etch chemistries, such as isotropic wet etchants or vapor phase etchants, are used to eliminate this sacrificial layer with a high etch selectivity (100: 1) relative to other materials in the structure. For example, the anchor material or the connecting material can be arranged in the region without the sacrificial layer, so that a connection to the substrate can be produced. The electrode, piezoelectric layer, and anchor may be deposited over the sacrificial layer. Once formed, the release etch selectively removes the sacrificial layer, suspending the piezoelectric material in the suspension region. Two such examples of sacrificial materials and their corresponding high selectivity etchants are silicon (gaseous XeF)₂Etchant of) and germanium (H)₂O/H₂O₂Etchant in mixture). Such sacrificial materials have been successfully used in contemporary micro-electro-mechanical system (MEMS) device fabrication processes. The material of piezoelectric microactuator 310 preferably comprises lead zirconate titanate, lanthanum-doped lead zirconate titanate, lead magnesium niobate, lead zinc niobate, barium titanate, zinc oxide, aluminum nitride, strontium bismuth tantalate, or strontium bismuth titanate.

FIG. 7 is a top view of a read head 700 and a piezoelectric microactuator 710 according to another embodiment of the present invention. Read head 700 has an air bearing surface 702 and an opposing top surface 704. Read head 700 also has a trailing surface 706 that includes a read transducer (not shown) and may also include a write transducer or the like. The piezoelectric microactuator 710 has a first side 712 and an opposing second side (not visible in FIG. 7 because it is on the bottom side of the piezoelectric microactuator 710 facing the top surface 704 of the read head 700).

The first side 712 of the piezoelectric microactuator 710 faces and is generally parallel to a major surface of the flexure tongue (not shown in fig. 7 to provide an unobstructed view of the piezoelectric microactuator 710). The first side 712 of the piezoelectric microactuator 710 includes three anchor regions 720 that extend radially from a center point 722. In the embodiment of fig. 7, the aperture 724 extends through the piezoelectric microactuator 710 and the aperture 724 includes a center point 722. The holes 724 preferably have a diameter in the range of 0.1mm to 0.5. mm. Each of the anchor regions 720 is combined with a flexure tongue, which qualifies it as an "anchor" region. The first side 712 of the piezoelectric microactuator 710 also includes three unbonded regions (regions between anchor regions 720) that are not bonded to the flexure tongue. Each of the unbonded regions is located between two of the anchor regions 720.

Each of the plurality of anchor regions 710 is preferably an anchor plateau that protrudes from the first side 712 in a direction approximately perpendicular to the tab major surface. In such embodiments, each unbonded area (between anchor areas 720) is recessed from the flexure tongue major surface relative to adjacent anchor plateaus. Alternatively, however, the anchor regions 720 may be formed by a distribution of adhesive only, rather than by any actual plateau in the piezoelectric microactuator 710. Alternatively, a plurality of recesses may be etched into the flexure tongue to distinguish the anchor regions 720 and the unbonded regions therebetween.

The second side (bottom in the perspective view of fig. 7) of piezoelectric microactuator 710 includes a plurality of attachment regions 740 extending radially from center point 722. The connection regions 740 are shown in phantom lines because they are generally not visible from the perspective of fig. 7 (because they protrude downward from the bottom surface of the piezoelectric microactuator 710 in fig. 7). Each of the plurality of connection regions 740 is bonded to the top surface 704 of the read head 700. Three unbonded areas that do not bond to the top surface of the read head are located on the second side of the piezoelectric microactuator 710 between each pair of the plurality of link areas 740. It should be noted that each of the plurality of connection regions 740 is angularly spaced between two of the plurality of anchor regions 720. Preferably, in the embodiment of fig. 7, each of the connection regions 740 is angularly spaced between two of the plurality of anchor regions 720 at an average angular spacing of no greater than 60 °. Such inequality is preferred for embodiments that include at least three anchor regions 720 and at least three connecting regions 740.

Each of the plurality of land areas 740 is preferably a land that protrudes from the second side of the piezoelectric microactuator 710 in a direction that is approximately perpendicular to the top surface 704 of the read head 700. In such an embodiment, each unbonded region (between the link regions 740) is recessed from the top surface 704 of the read head 700 relative to the adjacent link plateaus. Alternatively, however, the connection regions 740 may be formed by a distribution of adhesive only, rather than by any actual plateaus in the piezoelectric microactuator 710. Alternatively, multiple recesses may be etched into the top surface of the read head (e.g., during a bar leveling stage of slider fabrication) to distinguish the connection regions 740 from non-bonded regions therebetween.

The embodiment of fig. 7 includes six wedge-shaped free regions 730 that are common to both the unbonded regions on the first side 712 (between anchor regions 720) and the unbonded regions on the second side (on the bottom side of the piezoelectric microactuator 710). The free regions 730 are bonded to neither the flexure tongue nor the read head 700, which is why they are referred to as "free" regions. In some embodiments, the free region 730 is not only free of engagement with the flexure tongue and read head 700, but is also free of contact with the flexure tongue and read head 700. In such embodiments, the free region 730 is also referred to as a "fly" region, and its interfacial friction with the flexure tongue and/or the read head 700 is negligible.

FIG. 8 is a top view of a read head 800 and a piezoelectric microactuator 810 according to another embodiment of the present invention. The read head 800 has an air bearing surface 802 and an opposing top surface 804. The read head 800 also has a trailing surface 806 that includes a read transducer (not shown) and may also include a write transducer or the like. The piezoelectric microactuator 810 has a first side 812 and an opposing second side (not visible in FIG. 8 because it is on the bottom side of the piezoelectric microactuator 810 facing the top surface 804 of the read head 800).

The first side 812 of the piezoelectric microactuator 810 faces and is generally parallel to a major surface of the flexure tongue (not shown in fig. 8 to provide an unobstructed view of the piezoelectric microactuator 810). The first side 812 of the piezoelectric microactuator 810 includes two anchor regions 820 that extend radially from a center point 822. In the embodiment of fig. 8, a hole 824 extends through the piezoelectric microactuator, and hole 824 includes center point 822. The holes 824 preferably have a diameter in the range of 0.1mm to 0.5. mm. Each of the anchor regions 820 is combined with a flexure tongue, which qualifies it as an "anchor" region. The first side 812 of the piezoelectric microactuator 810 also includes two non-bonded regions (angled regions between anchor regions 820) that are not bonded to the flexure tongue. Each located between two of the anchor regions 820.

Each of the plurality of anchor regions 810 is preferably an anchor plateau that protrudes from the first side 812 in a direction approximately perpendicular to the tongue major surface. In such embodiments, each unbonded area (angled between anchor areas 820) is recessed from the flexure tongue major surface relative to adjacent anchor plateaus. Alternatively, however, the anchor regions 820 may be formed by a distribution of adhesive only, rather than by any actual plateau in the piezoelectric microactuator 810. Alternatively, a plurality of recesses may be etched into the flexure tongue, thereby distinguishing the anchor regions 820 and the angled non-bonded regions therebetween.

The second side (bottom of the view of fig. 8) of piezoelectric microactuator 810 includes two connecting regions 840 extending radially from center point 822. The attachment regions 840 are shown in phantom because they are generally not visible in the view of fig. 8 (because they protrude downward from the bottom surface of the piezoelectric microactuator 810 in fig. 8). Each of the plurality of land regions 840 is bonded to the top surface 804 of the read head 800. Two non-bonded regions that are not bonded to the top surface of the read head are located on the second side of the piezoelectric microactuator 810 and are angularly spaced between the link regions 840. It should be noted that each connection region 840 is angularly spaced between two anchor regions 820. Preferably, in the embodiment of FIG. 8, each connection region 840 is angularly spaced between two of the plurality of anchor regions 820 at an average angular spacing of no more than 90.

Each land 840 is preferably a land that protrudes from the second side of the piezoelectric microactuator 810 in a direction approximately perpendicular to the top surface 804 of the read head 800. In such an embodiment, each unbonded region (angled between anchor regions 820) is recessed from the top surface 804 of the read head 800 relative to adjacent link plateaus. Alternatively, however, the attachment region 840 may be formed by a distribution of adhesive only, rather than by any actual plateau in the piezoelectric microactuator 810. Alternatively, a plurality of recesses may be etched into the top surface 804 of the read head 800 (e.g., during a slider fabrication bar leveling stage) to distinguish the connection region 840 from angled non-bonded regions therebetween.

The embodiment of fig. 8 includes four wedge-shaped free regions 830 that are common to both the unbonded regions on the first side 812 (angled between the anchor regions 820) and the unbonded regions on the second side (the bottom surface of the piezoelectric microactuator 810). The free regions 830 are bonded to neither the flexure tongue nor the read head 800, which is why they are referred to as "free" regions. In some embodiments, the free region 830 is not only free from engagement with the flexure tongue and read head 800, but is also free from contact with the flexure tongue and read head 800. In such embodiments, the free region 830 is also referred to as a "fly" region, and its interfacial friction with the flexure tongue and/or the read head 800 is negligible.

In the foregoing specification, the invention has been described with reference to specific exemplary embodiments, but those skilled in the art will recognize that the invention is not limited thereto. It is contemplated that various features and aspects of the invention may be used independently or jointly and possibly in different environments or applications. The specification and drawings are, accordingly, to be regarded in an illustrative and exemplary sense rather than a restrictive sense. "comprising," "including," and "having" are intended to be open-ended terms.

Claims

1. A Head Gimbal Assembly (HGA), comprising:

a read head having an air bearing surface and an opposing top surface;

a load beam;

a flexure connected to the load beam, the flexure including a tongue having a tongue major surface;

a piezoelectric microactuator having a first side and an opposing second side, the first side facing the tab major surface and being generally parallel thereto,

wherein the first side comprises

A plurality of anchor regions extending radially from a central point, each of the plurality of anchor regions being bonded to the tab, an

A first plurality of unbonded areas not bonded to the tab, each of the first plurality of unbonded areas positioned between two of the plurality of anchor areas, and wherein the second side comprises

A plurality of link regions extending radially from a center point, each of the plurality of link regions bonded to the top surface of the read head, an

A second plurality of unbonded areas not bonded to the top surface of the read head, each of the second plurality of unbonded areas being located between two of the plurality of link areas, an

Wherein each of the plurality of connection regions is angularly spaced between two of the plurality of anchor regions.

2. A head suspension assembly as recited in claim 1, wherein each of the plurality of anchor regions is an anchor plateau that protrudes from the first side surface in a direction approximately perpendicular to the tongue major surface.

3. The head suspension assembly of claim 2, wherein each of the first plurality of unbonded areas is recessed from the tongue major surface relative to an adjacent anchor plateau.

4. A head suspension assembly as claimed in claim 2, wherein each of said anchor plateaus comprises a malleable metal layer and an insulating layer.

5. A head suspension assembly as claimed in claim 4, wherein said malleable metal layer comprises gold and said insulating layer comprises silicon dioxide.

6. The head suspension assembly of claim 3, wherein the adjacent anchor plateau protrudes from the first side surface in a direction approximately perpendicular to the tongue major surface by 1 to 20 microns relative to at least one of the first plurality of unbonded areas.

7. A head suspension assembly as recited in claim 1 wherein each of the plurality of connection regions is a connection plateau that protrudes from the second side in a direction approximately perpendicular to a top surface of the read head.

8. The head suspension assembly of claim 7, wherein each of the second plurality of unbonded regions is recessed from a top surface of the read head relative to an adjacent connecting plateau.

9. A head suspension assembly as claimed in claim 7, wherein each of said connection mesas comprises a malleable metal layer and an insulating layer.

10. A head suspension assembly as claimed in claim 9, wherein said malleable metal layer comprises gold and said insulating layer comprises silicon dioxide.

11. The head suspension assembly of claim 8, wherein the adjacent link plateau protrudes from a second side of the read head in a direction approximately perpendicular to the top surface of the read head by 1 to 20 microns relative to at least one of the second plurality of unbonded regions.

12. The head suspension assembly of claim 1, wherein the piezoelectric microactuator comprises a material selected from the group consisting of lead zirconate titanate, lanthanum-doped lead zirconate titanate, lead magnesium niobate, lead zinc niobate, barium titanate, zinc oxide, aluminum nitride, strontium bismuth tantalate, and strontium bismuth titanate.

13. A head suspension assembly as recited in claim 1, wherein the piezoelectric microactuator comprises a laminate structure including a plurality of piezoelectric sublayers and a plurality of conductive layers, and wherein each of the plurality of piezoelectric sublayers is separated from another of the plurality of piezoelectric sublayers by one of the plurality of conductive layers.

14. A head suspension assembly as recited in claim 13, wherein each of the plurality of conductive layers is approximately parallel to the tongue major surface.

15. A head suspension assembly as recited in claim 13, wherein each of the plurality of piezoelectric sublayers has a thickness in a range of 0.1 to 2 microns.

16. A head suspension assembly as recited in claim 1, wherein the piezoelectric microactuator has a maximum thickness, measured approximately perpendicular to the tongue major surface, in the range of 5 to 50 microns.

17. The head suspension assembly of claim 1, wherein the plurality of anchor regions includes at least four anchor regions, and wherein the plurality of link regions includes at least four link regions, and wherein at least one of the plurality of link regions is angularly spaced between two of the plurality of anchor regions at an average angular spacing of no greater than 45 °.

18. The head suspension assembly of claim 1 wherein the plurality of anchor regions consists of three anchor regions, and wherein the plurality of link regions consists of three link regions, and wherein at least one of the plurality of link regions is angularly spaced between two of the plurality of anchor regions at an average angular spacing of no greater than 60 °.

19. A head suspension assembly as claimed in claim 1, further comprising a hole through said piezoelectric microactuator, the hole comprising said center point.

20. A head suspension assembly as claimed in claim 19, wherein the aperture has a diameter in the range of 0.1mm to 0.5 mm.

21. A head gimbal assembly HGA, comprising:

a read head having an air bearing surface and an opposing top surface;

a load beam;

the first side being bonded to the tongue major surface by a plurality of anchor regions extending radially from a center point, the second side being bonded to the top surface of the read head by a plurality of link regions extending radially from the center point,

wherein each of the plurality of connection regions is angularly spaced between two of the plurality of anchor regions, and

wherein the piezoelectric microactuator comprises a plurality of suspension regions, each of the plurality of suspension regions being suspended between one of the plurality of link regions and an adjacent one of the plurality of anchor regions, and

wherein each of the plurality of suspension regions does not contact the tab and does not contact the read head.

22. A head suspension assembly as claimed in claim 21, further comprising a hole through the piezoelectric microactuator, the hole comprising the center point.

23. A head suspension assembly as recited in claim 21, wherein the piezoelectric microactuator comprises a laminate structure including a plurality of piezoelectric sublayers and a plurality of conductive layers, and wherein each of the plurality of piezoelectric sublayers is separated from another of the plurality of piezoelectric sublayers by one of the plurality of conductive layers.

24. The head suspension assembly of claim 21 wherein the plurality of anchor regions includes two anchor regions, and wherein the plurality of link regions includes two link regions, and wherein at least one of the plurality of link regions is angularly spaced between the two anchor regions at an average angular spacing of no greater than 90 °.