CA2221966A1 - Suspension with integrated conductor having controlled capacitance - Google Patents
Suspension with integrated conductor having controlled capacitance Download PDFInfo
- Publication number
- CA2221966A1 CA2221966A1 CA002221966A CA2221966A CA2221966A1 CA 2221966 A1 CA2221966 A1 CA 2221966A1 CA 002221966 A CA002221966 A CA 002221966A CA 2221966 A CA2221966 A CA 2221966A CA 2221966 A1 CA2221966 A1 CA 2221966A1
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- Canada
- Prior art keywords
- flexure
- head
- boundary
- void
- traces
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/486—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives with provision for mounting or arranging electrical conducting means or circuits on or along the arm assembly
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4853—Constructional details of the electrical connection between head and arm
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B25/00—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus
- G11B25/04—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus using flat record carriers, e.g. disc, card
- G11B25/043—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus using flat record carriers, e.g. disc, card using rotating discs
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/012—Recording on, or reproducing or erasing from, magnetic disks
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B5/027—Analogue recording
- G11B5/035—Equalising
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4813—Mounting or aligning of arm assemblies, e.g. actuator arm supported by bearings, multiple arm assemblies, arm stacks or multiple heads on single arm
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4833—Structure of the arm assembly, e.g. load beams, flexures, parts of the arm adapted for controlling vertical force on the head
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B2005/0002—Special dispositions or recording techniques
- G11B2005/0005—Arrangements, methods or circuits
- G11B2005/001—Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure
- G11B2005/0013—Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure of transducers, e.g. linearisation, equalisation
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/20—Disc-shaped record carriers
- G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
- G11B2220/2508—Magnetic discs
- G11B2220/2516—Hard disks
Landscapes
- Supporting Of Heads In Record-Carrier Devices (AREA)
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
- Networks Using Active Elements (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Abstract
A suspension (10) having integrated conductors (16) for supporting and electrically interconnecting a read/write head (36) to electronic circuitry in a disk drive. The capacitance to ground of the conductors (16) is controlled by the selective placement of shaped voids (20) in the suspension (10) at regions adjacent to the conductor paths. Portions of the suspension (10) may be generally the complement of the conductor structure (16) shape.
Description
W O 97/36290 PCTrUS97/0~346 SUSPENSION Wlrl ~ INTEGRATED C~ONDUCTOR
~IAVING CONTROT,T,li',n CAPACITANCE
Field of the Invention s This invention relates generally to structure and method of controlling capacitance and impedance ~ri.cin~ from integral conductors in a suspension for supporting a read/write head adjacent to a relatively moving recording medium in a disk drive. More particularly, it relates to an integrated suspension and 10 con~-lctor stucture wherein the suspension includes voids such that portions of the suspension are generally the complement of the conductor structure and a method for fabricating the same.
Back~round Contemporary disk drives typically include a rotating rigid storage disk and a head positioner for positioning a data transducer at different radial locations relative to the axis of rotation of the disk, thereby defining numerous concentric data storage tracks on each recording surface of the disk. The head 2 0 positioner is typically referred to as an actuator. Although numerous actuator structures are known in the art, in-line rotary voice coil actuators are now most frequently employed due to their simplicity, high performance, and their abilityto be mass balanced about their axis of rotation, the latter being important form~kins~ the actuator less sensitive to perturbations A closed-loop servo system is 2 5 employed to operate the actuator and thereby position the heads with respect to -~the disk surface.
W 097/36290 PCT~US9710~346 The read/write transducer, which may be of a single or dual element design, is typically deposited upon a ceramic slider structure having an air bearing surface for supporting the transducer at a small distance away from the 5 surface of the moving medium. Single element designs typically require two wire connections while dual element designs require four. Magnetoresistive (MR) heads, in particular, generally require four wires. The combination of an air bearing slider and a read/write transducer is also known as a read/write head or a recording head.
Sliders are generally mounted to a gimbaled ~exure structure attached to the distal end of a suspension's load beam structure. A spring biases the load be~m, and the~ ough the head, towards the disk, while the air pressure beneath the head pushes the head away from the disk. The equilibrium ~ t~nce then 15 ~1etermin~s the "flying height" of the head. By utili7.in~ such an "air bearing" to support the head away from the disk surface, the head operates in a hydrodynamically lubricated regime at the head/disk interface rather than in a boundary lubricated regime. The air bearing m~int~in~ spacing between the transducer and the medium which reduces transducer efficiency, however, the 2 0 avoidance of direct contact vastly improves the reliability and useful life of the head and disk components. Demand for increased areal densities may nonetheless require that heads be operated in pseudo contact or even boundary lubricated contact regimes, however.
2 ~ The disk drive industry has been progressively decreasing the size and mass ~of the slider structures in order to reduce the moving mass of the actuator W O 97/36290 PCTrUS97/05346 assembly and to permit closer operation of the transducer to the disk surface, the former giving rise to improved seek performance and the latter giving rise to improved transducer efficiency that can then be traded for higher areal density.The size (and therefore mass) of a slider is usually characterized with reference S to a so-called standard 100% slider (mini~lider). The terms 70%, 50%, and 30%
slider ~microslider, nanoslider, and picoslider, respectively) therefore refer to more recent low mass sliders that have linear dimensions that are scaled by the applicable percentage relative to the ~inear dimensions of a standard mini~liderSmaller slider structures generally require more compliant gimbals, hence the intrinsic stiffness of the conductor wires attached to the slider can give rise to a significant bias effect.
To reduce the effects of this intTin~ic wire stiffness or bias, integrated flexure/conductor structures have been proposed which effectively integrate the wires with an ins~ tin~ flexible polymeric resinous flexure such that the conductors are exposed at bonding pads positioned at the distal end of the flexure in the proximity of the head. U.S. Patent No. 5,006,946 to Matsuzaki discloses an example of such a configuration. While such wiring configurations do enjoy certain pelrollllance and assembly advantages, the introduction of the disclosed2 0 flexible polymeric resinous material in the flexure and gimbal structure raises a number of challenging design issues. For example, the thermal expansion properties of the resinous m~teri~l is not the same as the prior art stainless steel structures and the long-term durability of such resinous structures, including any requisite adhesive layers, is unknown. Therefore, hybrid stainless steel flexure2 5 and conductor structures have been proposed which incorporate most of the -~bene~lts of the integrated conductor flex-circuit flexure structures while W O 97136290 PCTrUS97/05346 rem~ining largely compatible~with prior art fabrication and loadbeam attachment methods. Such hybrid designs typically employ stainless steel flexures having deposited ins~ tin~ and conductive layers for electrical interconnection of the head to the associated drive electronics, e.g., a preamp chip and read channel 5 circuitry.
These hybrid flexure designs employ relatively lengthy runs of conductors which extend from bonding pads at the distal, head-mounting end of the flexure to the proximal end of the flexure to provide a conductive path from the 1 0 read~write head along the length of the associated suspension structure to the preamp or read-channel chip(s). Because the conductors are positioned extremely close to but electrically isolated from the conductive sf~inless steelflexure structure which is in turn grounded to the load beam, the m~.~nit~l-le of the conductor capacitance to ground is increased relative to a conventional 15 insulated discrete wire twisted pair con~ ctor structure. This increased capacitance tends to deleteriously affect the performance of the readlwrite head, conductor, and preamp system, hence there is a need for a manufacturable and reliable integrated flexure and conductor structure which exhibits reduced capacitance to ground.
The invention to be described provides, inter alia, a flexure for a suspension in a disk drive which includes integrated conductor structure configured to limit the parasitic capacitance between the conductor structure and other parts of the suspension structure and a method for fabricating the same.
-~ Sllmm~ry of the Invention W O 97/36290 PCTAUS97/0~346 A suspension assembly in accordance with a preferred embodiment of the invention includes a flexure having one or more shaped voids and having integrated conductors which extend along the flexure generally adjacent to the 5 voids. The integral conductors replace prior art discrete twisted-pair, insulated conductor wires which woùld normally extend along the length of the associated suspension. The size and shape of the flexure voids as well as the conductor geometry are controlled to reduce undesirable effects of conductor capacitance to ground. Additionally, the conductor traces may be configured to reduce the 10 mutual capacitance of ,the traces. The invention provides improved electrical performance without materially affecting the suspension' s mechanical performance.
A general object of the present invention is to provide a low-profile, 15 robust, reliable, suspension having integral conductors for electrically interconnecting a read/write head to associated read/write circuitry which overcomes limitations and drawbacks of the prior art.
A more specific object of the present invention is to provide a method to O control the capacitance or impedance of an integrated f~exure/conductor structure for use with a read/write head in a disk drive.
Still another object of the invention is to provide an integrated flexure and conductor structure and fabrication method that facilitates the separate 5 opt;mi7~tion of the capacitances and impedances of the conductors of both the -read and the write elements of a dual-element read/write head.
W O 97/36290 PCTrUS97/05346 Another object of the invention is to provide an improved suspension for supporting read/write heads in the drive.
The invention provides an economical and reliable method for electrically interconnecting a transducer mounted on a slider to an integrated flexure/conductor structure which implements a gimbal and includes exposed conductive electrical bonding pads positioned near the slider mounting region atthe distal end of a conductive flexure. The bonding pads and associated conductors are electrically isolated from the flexure ~y a dielectric layer affixed to the flexure with the conductors extending generally coplanarly along a flexure surface. The flexure includes one or more voids and the conductors are configured to extend adjacent to the voids. The conductor aspect ratio and the interconductor spacing may be tailored to reduce the mutual capacitance between l S conductors while concurrently m~int~ining low capacitance to ground. The boundaries of the voids may ~e configured to prevent discontinuous impedance changes along the conductor path.
These and other objects, advantages, aspects, and features of the present 2 0 invention will be more fully appreciated and understood upon consideration of the following detailed descriptions of a preferred embodiment presented in conjunction with the accompanying dlawhlgs.
Brief Description of the Drawin~s -~n the Drawings:
Pig. 1 is an enlarged diagr~mm~tic plan view of an integrated flexure/conductor structure in accordance with the invention.
S Fig. 2 shows a cross section of the integrated flexure/conductor structure of Fig.
1 taken along section line A-A.
Fig. 2A illustrates an alternative cross sectional detail of an integrated flexure/conductor structure of the type illustrated in Fig. 1.
Fig. 3 is an enlarged diagr~mm~tic plan view of a head gimbal assembly (HGA) in accordance with the invention which includes a loadbeam, an integrated flexure/conductor structure, and a read/write head.
l S Fig. 4 illustrates a graph showing conductor capacitance to ground versus adjacent void width.
Fig. 5A - ~D illustrate a variety of exemplary void outlines which may be defined in an integrated flexure/conductor structure in accordance with the invention.
Fig. 6 illustrates an equivalent circuit diagram of a typical read circuit, conductor, and read/write head system which employs an integrated-conductor type conductive flexure member.
.
Fig. 7 is a graph modeling the kansfer function of the circuit of Fig. 6 assuming a typical capacitance-to-ground value for a flexure having no voids adjacent theconductors.
S Fig. 8 is a graph modeling the transfer function of the circuit of Fig. 6 assuming a typical capacitance-to-ground value achievable by employing voids adjacent theconductors.
Fig. 9 illustrates a plan view of a disk drive in accordance with the invention.1 0 Detailed Description of a Preferred Embodiment Referring to the drawings, where like characters designate like or corresponding parts throughout the views, Fig. 1 is a plan view of an integrated15 flexure/conductor structure 10 in accordance with a preferred embo-liment of the invention. Flexure/conductor structure 10 includes a generally planar stainless steel flexure member 12 which is appr-)xim~tely 20-microns thick and which includes tooling holes 14 and 15 which are used during manufacturing and assembly for precision component alignment. A pair of conductive traces of 20 approxim~tely 10-microns thick copper form part of a conductor structure 16 which extends from the proximal end 17 of flexure member 12 to the head supporting distal end 18 of flexure member 12. Conductor structure 16 includes a thin (e.g., 10-microns) insulating base film 25 (omitted for clarity but shown in Fig. 2) interposed between the conductive traces of the conductor structure and 2 5 stainless steel flexure member 12 to prevent shorting of the conductive traces of ~conductor structure 16. Flexure member 12 includes one or more voids 20 W O 97/36290 PCT~US97/05346 which are positioned adjacent to the path along which conductor structure 16 is routed to reduce the capacitance between the conductor structure and the stainless steel flexure member 12. Accordingly, the invention provides a method for conkolling the capacitance ~ri~in~ ~rom the integration of the conductor structure 5 16 with the stainless steel flexure member 12. As is well known in the art, excessive conductor or lead wire capacitance has a deleterious impact on signalstraveling between the associated read/write head and preamp circuit.
Additionally, because at sufficiently high frequencies conductor structure 10 16 behaves as a tr~n.~mi~ion line for si~n~l~ passing between the read/write head and read channel electronics, the geometry of the voids is an important factor for controlling and avoiding abrupt impedance changes along the signal path of conductor structure 16. Discontinuous impedance changes tend to give rise to undesireable reflection effects in the tr~n~mi~ion line. Fig. 2 illustrates a cross 15 section of the ~exure/conductor structure 10 of Fig. 1 taken along section line A-A. ~onductor structure l6 includes, in this embodiment, a pair of conductive traces 22 and an ins~ tin~ polyimide (a flexible polymeric resinous material) layer 24 which spans the void 20 to provide support for the conductive traces. In this embodiment, the pair of traces are configured as close together as the 20 fabrication process reliably permits to reduce the magnitude of the mutual capacitance between the conductors. Although not strictly required, an additional insulation layer of about 4-microns thickness may be used as a protective overcoat for the traces 22. Plefellably, the voids should be shaped so as to cause a smooth or relativel,v continuous change in the cross sectional area of the void 20 2 5 along the length of flexure/conductor structure 10 so as to avoid abrupt --transitions in the impedance along the signal path defined by conductor structure ~ =
W O 97/36290 PCTnUS97/05346 16. In the areas where the b~undaries of the void(s) 20 cross the traces 22, it is desirable to either curve the boundary or angle the boundary so that the boundary does not cross the traces at a right angle so that the impedance changes along the tran~mi~sion line defined by conductive structure 16 are made more gradual.
S Additionally, the flexure member interior boundary that defines void(s) 20 maybe undercut (as shown in Fig. 2 or 2A) to further smooth impedance changes along the signal path.
Numerous methods for l~min~ting and p~tt~rnin~ stainless steel sheet stock, 10 dielectric films, and conductors are known in the art. Additionally, methods for depositing and pa~L~ illg dielectrics and conductors onto stainless steel are also known in the art. In accordance with a preferred embodiment of the invention, the conductive traces 22 are plated and photolithographically defined, rather than in~te-l and etched, so that the insulation and conductive trace layers may be 15 made suitably thin so as not to materially affect the mechanical properties of the stainless steel flexure member. After the in~ tQr and conductor structures are formed, the outlines of the flexure and the voids may be selectively etched to complete the formation of an intergrated flexurelconductor structure.
2 0 Fig. 3 shows a fully assembled head gimbal assembly (HGA) 30 in accordance with the invention which includes a baseplate 32 for mounting the HGA to an actuator arm in a disk drive and a loadbeam 34 for applying a load force onto read/write head 36. Head 36 is affixed to the distal end 18 of flexure/conductor structure 10 and the transducer element(s) (not shown) of read/write head 36 are electrically interconnected to the conductive traces 22.
--~lexurefconductor structure 10 may be conventionally spot welded to loadbeam -W O 97/36290 PCTrUS97/05346 34. Loadbeam 34 typically includes a protuberance or load button (not shown) which approxim~teS point contact between loadbeam 34 and read/write head 36 so that head 36 is capable of limited relative pitch and roll with respect to loadbeam 35. It should be noted that although loadbeam 34 is a conductive stainless steelS structure (like flexure member 12) in the preferred embodiment of the invention, the conductive traces 22 are positioned sufficiently far from the loadbeam structure so as not to give rise to significant capacitance to ground concerns with respect to the loadbeam. If however, a loadbeam structure having an integrated gimbal is employed so that the intermediate flexure body member described in 10 connection with Fig. 2 is not required, in accordance with the principles of the invention, the loadbeam itself may be etched so as to include voids along the signal path to reduce capacitance to ground.
Fig. 4 illustrates a graph 40 plotting capacitance to ground as a function of l S the width of the void 22 when t_e flexure is af~lxed to a grounded loadbeam. Graph 42 shows only minor capacitance reductions in the case where the grounded loadbeam is not present. Thus, it is not necessary to fabricate or etchvoids into the loadbeam itself, unless, for example, the conductors are integrated with a loadbeam having an integral gimbal that is not implemented with a 2 0 separate flexure member. Retu~ g to graph 40, if the void width is made too small, the capacitance rem~in~ relatively high, however, if the void width is made too large, a point of ~limini.ching returns is reached and structural rigidity may be unecessarily compromised. The appropriate void width is ultimately dependent upon the specific conductor configuration under ex~min~tion but can be readily 25 determined either via modeling or empirically. It should be noted that the -capacitance to ground can also be reduced by increasing the thicl~ness of the W 0 97/36290 PCTrUS97/05346 insulating layer, however, t~is ~olution is not desirable because it tends to increase the thickness of the resultant suspension and because the added material and associated mass may give rise to adverse mechanical effects. Also, narrower conductive traces may be employed to reduce capacitance to ground, however the S narrower conductive traces exhibit undesirable increases in conductor resistance.
Thus, the use of precision shaped voidLs facilitates the fabrication of potentially thinner suspension structures having integrated conductors that offer improved electrical performance.
Figs. 5A - SD illustrate several alternative void shapes that may be employed adjacent to either the read or write signal path to control the capacitance of that signal path. Fig. 5A illustrates a substantially rectangularinterior boundary de~ming a void in a flexure member. Although the illustrated void helps to reduce the m~nitude of the capacitance to ground, the 15 perpendicular crossing of the conductor and the void boundary can give rise to a sharp or step-function transition in the impedance a~ong the conductor path.
For a single conductor, the capacitance per unit length is approxim~ted by:
Clg = 8.84~,~C(bt)Pflm 2 0 whe~e:
Cg = capacitance to ground = length of conductor ~r= dielectric constant Kc = capacitiYe fringing factor 2 S b = conductor width ~ t = thickness of insulator W O 97J36290 PCTrUS97/05346 The capacitance to ground of the conductor regions near the boundary but adjacent the conductive flexure member is therefore substantially different fromthe capacitance to ground of the conductor regions near the boundary but ad3acent the void. This abrupt capacitance change gives rise to an approximatelystep-function impedance change in the conductor as it crosses the boundary.
In high frequency applications, step function changes in impedance along the conductor path cause traveling wave reflections that distort the transmittedwaveforrn. Therefore, curved or angled void boundaries such as those disclosed 10 in Figs. SB-5D appear to provide better high frequency per~ormance than the void boundary illustrated in 5A. Of course, the thickness of the flexure member,which acts as a ground plane, may also be varied (Fig. 2A) to cause a more gradual impedance change for any of the void geometries illustrated in Figs. 5A-5D. It should be noted that the void boundary may be either an interior or 15 exterior boundary of the flexure member, since voids may be forrned along a lateral edge of the flexure member, for example.
Fig. 6 shows an equivalent circuit diagram representing a characteristic transmission line model 49 of a typical read circuit, conductor, and O magnetoresistive (MR) read head system which employs an integrated conductor type stainless steel flexure. MR head equivalent circuit SO is a conventional model of a lSO-kfci (kilo flux changes per inch) read element. Conductive trace ec~uivalent circuit 52 represents the conductive traces adjacent a grounded, conductive flexure structure. Forward and rearward looking capacitances to 5 ground arising from the conductor traces are represented by capacitors 53 and ~4. A driving source 56 is swept from about 10-mhz to 5-Ghz to analyze the W O 97/36290 PCTrUS97/05346 frequency driven transfer function of the overall circuit. ~igs. 7 and 8 show modeling results of the transfer functions of the circuit for the cases where there are no voids in the flexure adjacent the traces and where there are voids in flexure, respectively. In the former case, the forward looking and rearward 5 looking capacitance to ground is assumed to be on the order of about 14-picofarads, whereas, with the voids, the forward looking and rearward looking conductor capacitance to ground may readily be reduced to about 4-picofarads.
Without the voids, the modeled circuit has a reduced bandwidth and earlier rolloff than the same structure employing voids in accordance with the invention.
10 Thus, an integrated-conductor flexure in accordance with the invention provides better bandwith and a higher cutoff frequency in the head circuit. Moreover, theoverall circuit behaves as a b~nt1p~s ~llter and exhibits a higher Q with the voids.
Those skilled in the art will recognize that, in accordance with the 15 principles of the invention, advanced dual element transducer designs (such as an MR head ~lesign) may have the capacitances and/or impedances of the signal pathsof the read and write elements separately optimized by employing different conductor geometries and/or the void configurations for the read and write conductive traces, respectively.
Fig. 9 illustrates an integrated-conductor ~exure employed in the context of a disk drive. Disk drive 70 includes a rigid base 75 and a rotating storage disk 80 which is rotatably mounted with respect to base 75 via conventional spindle motor means (not shown). Drive 70 also includes a rotary actuator assembly 82 2 5 which includes a voice-coil 84 that, when selectively energized, is used to move ~nd position ~IGA 30 (discussed in greater detail in connection with Pig. 3), and W O 97/36290 - PCTrUS97/Q5346 therethrough head 36, relative to a radius of disk 80. Flex circuit 82 is electrically connected to the conductors on flexure 10 to facilitate comm~ ication between head 36 and remotely located signal processing circuitry (not shown).
Although the present invention has been described in terms of the presently preferred embodiment, i.e., a deposited conductor flexure structure which implements a gimb~l, it should be clear to those skilled in the art that the present invention may also be utilized in conjunction with, for example, an integrated gimbal loadbeam structure, or other conductive suspension members having proxim~tely mounted, deposited, or embedded conductors with or without ins~ tin~; overcoatings. Thus, it should be understood that the instant disclosure is not to be inlel~lcled as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
~IAVING CONTROT,T,li',n CAPACITANCE
Field of the Invention s This invention relates generally to structure and method of controlling capacitance and impedance ~ri.cin~ from integral conductors in a suspension for supporting a read/write head adjacent to a relatively moving recording medium in a disk drive. More particularly, it relates to an integrated suspension and 10 con~-lctor stucture wherein the suspension includes voids such that portions of the suspension are generally the complement of the conductor structure and a method for fabricating the same.
Back~round Contemporary disk drives typically include a rotating rigid storage disk and a head positioner for positioning a data transducer at different radial locations relative to the axis of rotation of the disk, thereby defining numerous concentric data storage tracks on each recording surface of the disk. The head 2 0 positioner is typically referred to as an actuator. Although numerous actuator structures are known in the art, in-line rotary voice coil actuators are now most frequently employed due to their simplicity, high performance, and their abilityto be mass balanced about their axis of rotation, the latter being important form~kins~ the actuator less sensitive to perturbations A closed-loop servo system is 2 5 employed to operate the actuator and thereby position the heads with respect to -~the disk surface.
W 097/36290 PCT~US9710~346 The read/write transducer, which may be of a single or dual element design, is typically deposited upon a ceramic slider structure having an air bearing surface for supporting the transducer at a small distance away from the 5 surface of the moving medium. Single element designs typically require two wire connections while dual element designs require four. Magnetoresistive (MR) heads, in particular, generally require four wires. The combination of an air bearing slider and a read/write transducer is also known as a read/write head or a recording head.
Sliders are generally mounted to a gimbaled ~exure structure attached to the distal end of a suspension's load beam structure. A spring biases the load be~m, and the~ ough the head, towards the disk, while the air pressure beneath the head pushes the head away from the disk. The equilibrium ~ t~nce then 15 ~1etermin~s the "flying height" of the head. By utili7.in~ such an "air bearing" to support the head away from the disk surface, the head operates in a hydrodynamically lubricated regime at the head/disk interface rather than in a boundary lubricated regime. The air bearing m~int~in~ spacing between the transducer and the medium which reduces transducer efficiency, however, the 2 0 avoidance of direct contact vastly improves the reliability and useful life of the head and disk components. Demand for increased areal densities may nonetheless require that heads be operated in pseudo contact or even boundary lubricated contact regimes, however.
2 ~ The disk drive industry has been progressively decreasing the size and mass ~of the slider structures in order to reduce the moving mass of the actuator W O 97/36290 PCTrUS97/05346 assembly and to permit closer operation of the transducer to the disk surface, the former giving rise to improved seek performance and the latter giving rise to improved transducer efficiency that can then be traded for higher areal density.The size (and therefore mass) of a slider is usually characterized with reference S to a so-called standard 100% slider (mini~lider). The terms 70%, 50%, and 30%
slider ~microslider, nanoslider, and picoslider, respectively) therefore refer to more recent low mass sliders that have linear dimensions that are scaled by the applicable percentage relative to the ~inear dimensions of a standard mini~liderSmaller slider structures generally require more compliant gimbals, hence the intrinsic stiffness of the conductor wires attached to the slider can give rise to a significant bias effect.
To reduce the effects of this intTin~ic wire stiffness or bias, integrated flexure/conductor structures have been proposed which effectively integrate the wires with an ins~ tin~ flexible polymeric resinous flexure such that the conductors are exposed at bonding pads positioned at the distal end of the flexure in the proximity of the head. U.S. Patent No. 5,006,946 to Matsuzaki discloses an example of such a configuration. While such wiring configurations do enjoy certain pelrollllance and assembly advantages, the introduction of the disclosed2 0 flexible polymeric resinous material in the flexure and gimbal structure raises a number of challenging design issues. For example, the thermal expansion properties of the resinous m~teri~l is not the same as the prior art stainless steel structures and the long-term durability of such resinous structures, including any requisite adhesive layers, is unknown. Therefore, hybrid stainless steel flexure2 5 and conductor structures have been proposed which incorporate most of the -~bene~lts of the integrated conductor flex-circuit flexure structures while W O 97136290 PCTrUS97/05346 rem~ining largely compatible~with prior art fabrication and loadbeam attachment methods. Such hybrid designs typically employ stainless steel flexures having deposited ins~ tin~ and conductive layers for electrical interconnection of the head to the associated drive electronics, e.g., a preamp chip and read channel 5 circuitry.
These hybrid flexure designs employ relatively lengthy runs of conductors which extend from bonding pads at the distal, head-mounting end of the flexure to the proximal end of the flexure to provide a conductive path from the 1 0 read~write head along the length of the associated suspension structure to the preamp or read-channel chip(s). Because the conductors are positioned extremely close to but electrically isolated from the conductive sf~inless steelflexure structure which is in turn grounded to the load beam, the m~.~nit~l-le of the conductor capacitance to ground is increased relative to a conventional 15 insulated discrete wire twisted pair con~ ctor structure. This increased capacitance tends to deleteriously affect the performance of the readlwrite head, conductor, and preamp system, hence there is a need for a manufacturable and reliable integrated flexure and conductor structure which exhibits reduced capacitance to ground.
The invention to be described provides, inter alia, a flexure for a suspension in a disk drive which includes integrated conductor structure configured to limit the parasitic capacitance between the conductor structure and other parts of the suspension structure and a method for fabricating the same.
-~ Sllmm~ry of the Invention W O 97/36290 PCTAUS97/0~346 A suspension assembly in accordance with a preferred embodiment of the invention includes a flexure having one or more shaped voids and having integrated conductors which extend along the flexure generally adjacent to the 5 voids. The integral conductors replace prior art discrete twisted-pair, insulated conductor wires which woùld normally extend along the length of the associated suspension. The size and shape of the flexure voids as well as the conductor geometry are controlled to reduce undesirable effects of conductor capacitance to ground. Additionally, the conductor traces may be configured to reduce the 10 mutual capacitance of ,the traces. The invention provides improved electrical performance without materially affecting the suspension' s mechanical performance.
A general object of the present invention is to provide a low-profile, 15 robust, reliable, suspension having integral conductors for electrically interconnecting a read/write head to associated read/write circuitry which overcomes limitations and drawbacks of the prior art.
A more specific object of the present invention is to provide a method to O control the capacitance or impedance of an integrated f~exure/conductor structure for use with a read/write head in a disk drive.
Still another object of the invention is to provide an integrated flexure and conductor structure and fabrication method that facilitates the separate 5 opt;mi7~tion of the capacitances and impedances of the conductors of both the -read and the write elements of a dual-element read/write head.
W O 97/36290 PCTrUS97/05346 Another object of the invention is to provide an improved suspension for supporting read/write heads in the drive.
The invention provides an economical and reliable method for electrically interconnecting a transducer mounted on a slider to an integrated flexure/conductor structure which implements a gimbal and includes exposed conductive electrical bonding pads positioned near the slider mounting region atthe distal end of a conductive flexure. The bonding pads and associated conductors are electrically isolated from the flexure ~y a dielectric layer affixed to the flexure with the conductors extending generally coplanarly along a flexure surface. The flexure includes one or more voids and the conductors are configured to extend adjacent to the voids. The conductor aspect ratio and the interconductor spacing may be tailored to reduce the mutual capacitance between l S conductors while concurrently m~int~ining low capacitance to ground. The boundaries of the voids may ~e configured to prevent discontinuous impedance changes along the conductor path.
These and other objects, advantages, aspects, and features of the present 2 0 invention will be more fully appreciated and understood upon consideration of the following detailed descriptions of a preferred embodiment presented in conjunction with the accompanying dlawhlgs.
Brief Description of the Drawin~s -~n the Drawings:
Pig. 1 is an enlarged diagr~mm~tic plan view of an integrated flexure/conductor structure in accordance with the invention.
S Fig. 2 shows a cross section of the integrated flexure/conductor structure of Fig.
1 taken along section line A-A.
Fig. 2A illustrates an alternative cross sectional detail of an integrated flexure/conductor structure of the type illustrated in Fig. 1.
Fig. 3 is an enlarged diagr~mm~tic plan view of a head gimbal assembly (HGA) in accordance with the invention which includes a loadbeam, an integrated flexure/conductor structure, and a read/write head.
l S Fig. 4 illustrates a graph showing conductor capacitance to ground versus adjacent void width.
Fig. 5A - ~D illustrate a variety of exemplary void outlines which may be defined in an integrated flexure/conductor structure in accordance with the invention.
Fig. 6 illustrates an equivalent circuit diagram of a typical read circuit, conductor, and read/write head system which employs an integrated-conductor type conductive flexure member.
.
Fig. 7 is a graph modeling the kansfer function of the circuit of Fig. 6 assuming a typical capacitance-to-ground value for a flexure having no voids adjacent theconductors.
S Fig. 8 is a graph modeling the transfer function of the circuit of Fig. 6 assuming a typical capacitance-to-ground value achievable by employing voids adjacent theconductors.
Fig. 9 illustrates a plan view of a disk drive in accordance with the invention.1 0 Detailed Description of a Preferred Embodiment Referring to the drawings, where like characters designate like or corresponding parts throughout the views, Fig. 1 is a plan view of an integrated15 flexure/conductor structure 10 in accordance with a preferred embo-liment of the invention. Flexure/conductor structure 10 includes a generally planar stainless steel flexure member 12 which is appr-)xim~tely 20-microns thick and which includes tooling holes 14 and 15 which are used during manufacturing and assembly for precision component alignment. A pair of conductive traces of 20 approxim~tely 10-microns thick copper form part of a conductor structure 16 which extends from the proximal end 17 of flexure member 12 to the head supporting distal end 18 of flexure member 12. Conductor structure 16 includes a thin (e.g., 10-microns) insulating base film 25 (omitted for clarity but shown in Fig. 2) interposed between the conductive traces of the conductor structure and 2 5 stainless steel flexure member 12 to prevent shorting of the conductive traces of ~conductor structure 16. Flexure member 12 includes one or more voids 20 W O 97/36290 PCT~US97/05346 which are positioned adjacent to the path along which conductor structure 16 is routed to reduce the capacitance between the conductor structure and the stainless steel flexure member 12. Accordingly, the invention provides a method for conkolling the capacitance ~ri~in~ ~rom the integration of the conductor structure 5 16 with the stainless steel flexure member 12. As is well known in the art, excessive conductor or lead wire capacitance has a deleterious impact on signalstraveling between the associated read/write head and preamp circuit.
Additionally, because at sufficiently high frequencies conductor structure 10 16 behaves as a tr~n.~mi~ion line for si~n~l~ passing between the read/write head and read channel electronics, the geometry of the voids is an important factor for controlling and avoiding abrupt impedance changes along the signal path of conductor structure 16. Discontinuous impedance changes tend to give rise to undesireable reflection effects in the tr~n~mi~ion line. Fig. 2 illustrates a cross 15 section of the ~exure/conductor structure 10 of Fig. 1 taken along section line A-A. ~onductor structure l6 includes, in this embodiment, a pair of conductive traces 22 and an ins~ tin~ polyimide (a flexible polymeric resinous material) layer 24 which spans the void 20 to provide support for the conductive traces. In this embodiment, the pair of traces are configured as close together as the 20 fabrication process reliably permits to reduce the magnitude of the mutual capacitance between the conductors. Although not strictly required, an additional insulation layer of about 4-microns thickness may be used as a protective overcoat for the traces 22. Plefellably, the voids should be shaped so as to cause a smooth or relativel,v continuous change in the cross sectional area of the void 20 2 5 along the length of flexure/conductor structure 10 so as to avoid abrupt --transitions in the impedance along the signal path defined by conductor structure ~ =
W O 97/36290 PCTnUS97/05346 16. In the areas where the b~undaries of the void(s) 20 cross the traces 22, it is desirable to either curve the boundary or angle the boundary so that the boundary does not cross the traces at a right angle so that the impedance changes along the tran~mi~sion line defined by conductive structure 16 are made more gradual.
S Additionally, the flexure member interior boundary that defines void(s) 20 maybe undercut (as shown in Fig. 2 or 2A) to further smooth impedance changes along the signal path.
Numerous methods for l~min~ting and p~tt~rnin~ stainless steel sheet stock, 10 dielectric films, and conductors are known in the art. Additionally, methods for depositing and pa~L~ illg dielectrics and conductors onto stainless steel are also known in the art. In accordance with a preferred embodiment of the invention, the conductive traces 22 are plated and photolithographically defined, rather than in~te-l and etched, so that the insulation and conductive trace layers may be 15 made suitably thin so as not to materially affect the mechanical properties of the stainless steel flexure member. After the in~ tQr and conductor structures are formed, the outlines of the flexure and the voids may be selectively etched to complete the formation of an intergrated flexurelconductor structure.
2 0 Fig. 3 shows a fully assembled head gimbal assembly (HGA) 30 in accordance with the invention which includes a baseplate 32 for mounting the HGA to an actuator arm in a disk drive and a loadbeam 34 for applying a load force onto read/write head 36. Head 36 is affixed to the distal end 18 of flexure/conductor structure 10 and the transducer element(s) (not shown) of read/write head 36 are electrically interconnected to the conductive traces 22.
--~lexurefconductor structure 10 may be conventionally spot welded to loadbeam -W O 97/36290 PCTrUS97/05346 34. Loadbeam 34 typically includes a protuberance or load button (not shown) which approxim~teS point contact between loadbeam 34 and read/write head 36 so that head 36 is capable of limited relative pitch and roll with respect to loadbeam 35. It should be noted that although loadbeam 34 is a conductive stainless steelS structure (like flexure member 12) in the preferred embodiment of the invention, the conductive traces 22 are positioned sufficiently far from the loadbeam structure so as not to give rise to significant capacitance to ground concerns with respect to the loadbeam. If however, a loadbeam structure having an integrated gimbal is employed so that the intermediate flexure body member described in 10 connection with Fig. 2 is not required, in accordance with the principles of the invention, the loadbeam itself may be etched so as to include voids along the signal path to reduce capacitance to ground.
Fig. 4 illustrates a graph 40 plotting capacitance to ground as a function of l S the width of the void 22 when t_e flexure is af~lxed to a grounded loadbeam. Graph 42 shows only minor capacitance reductions in the case where the grounded loadbeam is not present. Thus, it is not necessary to fabricate or etchvoids into the loadbeam itself, unless, for example, the conductors are integrated with a loadbeam having an integral gimbal that is not implemented with a 2 0 separate flexure member. Retu~ g to graph 40, if the void width is made too small, the capacitance rem~in~ relatively high, however, if the void width is made too large, a point of ~limini.ching returns is reached and structural rigidity may be unecessarily compromised. The appropriate void width is ultimately dependent upon the specific conductor configuration under ex~min~tion but can be readily 25 determined either via modeling or empirically. It should be noted that the -capacitance to ground can also be reduced by increasing the thicl~ness of the W 0 97/36290 PCTrUS97/05346 insulating layer, however, t~is ~olution is not desirable because it tends to increase the thickness of the resultant suspension and because the added material and associated mass may give rise to adverse mechanical effects. Also, narrower conductive traces may be employed to reduce capacitance to ground, however the S narrower conductive traces exhibit undesirable increases in conductor resistance.
Thus, the use of precision shaped voidLs facilitates the fabrication of potentially thinner suspension structures having integrated conductors that offer improved electrical performance.
Figs. 5A - SD illustrate several alternative void shapes that may be employed adjacent to either the read or write signal path to control the capacitance of that signal path. Fig. 5A illustrates a substantially rectangularinterior boundary de~ming a void in a flexure member. Although the illustrated void helps to reduce the m~nitude of the capacitance to ground, the 15 perpendicular crossing of the conductor and the void boundary can give rise to a sharp or step-function transition in the impedance a~ong the conductor path.
For a single conductor, the capacitance per unit length is approxim~ted by:
Clg = 8.84~,~C(bt)Pflm 2 0 whe~e:
Cg = capacitance to ground = length of conductor ~r= dielectric constant Kc = capacitiYe fringing factor 2 S b = conductor width ~ t = thickness of insulator W O 97J36290 PCTrUS97/05346 The capacitance to ground of the conductor regions near the boundary but adjacent the conductive flexure member is therefore substantially different fromthe capacitance to ground of the conductor regions near the boundary but ad3acent the void. This abrupt capacitance change gives rise to an approximatelystep-function impedance change in the conductor as it crosses the boundary.
In high frequency applications, step function changes in impedance along the conductor path cause traveling wave reflections that distort the transmittedwaveforrn. Therefore, curved or angled void boundaries such as those disclosed 10 in Figs. SB-5D appear to provide better high frequency per~ormance than the void boundary illustrated in 5A. Of course, the thickness of the flexure member,which acts as a ground plane, may also be varied (Fig. 2A) to cause a more gradual impedance change for any of the void geometries illustrated in Figs. 5A-5D. It should be noted that the void boundary may be either an interior or 15 exterior boundary of the flexure member, since voids may be forrned along a lateral edge of the flexure member, for example.
Fig. 6 shows an equivalent circuit diagram representing a characteristic transmission line model 49 of a typical read circuit, conductor, and O magnetoresistive (MR) read head system which employs an integrated conductor type stainless steel flexure. MR head equivalent circuit SO is a conventional model of a lSO-kfci (kilo flux changes per inch) read element. Conductive trace ec~uivalent circuit 52 represents the conductive traces adjacent a grounded, conductive flexure structure. Forward and rearward looking capacitances to 5 ground arising from the conductor traces are represented by capacitors 53 and ~4. A driving source 56 is swept from about 10-mhz to 5-Ghz to analyze the W O 97/36290 PCTrUS97/05346 frequency driven transfer function of the overall circuit. ~igs. 7 and 8 show modeling results of the transfer functions of the circuit for the cases where there are no voids in the flexure adjacent the traces and where there are voids in flexure, respectively. In the former case, the forward looking and rearward 5 looking capacitance to ground is assumed to be on the order of about 14-picofarads, whereas, with the voids, the forward looking and rearward looking conductor capacitance to ground may readily be reduced to about 4-picofarads.
Without the voids, the modeled circuit has a reduced bandwidth and earlier rolloff than the same structure employing voids in accordance with the invention.
10 Thus, an integrated-conductor flexure in accordance with the invention provides better bandwith and a higher cutoff frequency in the head circuit. Moreover, theoverall circuit behaves as a b~nt1p~s ~llter and exhibits a higher Q with the voids.
Those skilled in the art will recognize that, in accordance with the 15 principles of the invention, advanced dual element transducer designs (such as an MR head ~lesign) may have the capacitances and/or impedances of the signal pathsof the read and write elements separately optimized by employing different conductor geometries and/or the void configurations for the read and write conductive traces, respectively.
Fig. 9 illustrates an integrated-conductor ~exure employed in the context of a disk drive. Disk drive 70 includes a rigid base 75 and a rotating storage disk 80 which is rotatably mounted with respect to base 75 via conventional spindle motor means (not shown). Drive 70 also includes a rotary actuator assembly 82 2 5 which includes a voice-coil 84 that, when selectively energized, is used to move ~nd position ~IGA 30 (discussed in greater detail in connection with Pig. 3), and W O 97/36290 - PCTrUS97/Q5346 therethrough head 36, relative to a radius of disk 80. Flex circuit 82 is electrically connected to the conductors on flexure 10 to facilitate comm~ ication between head 36 and remotely located signal processing circuitry (not shown).
Although the present invention has been described in terms of the presently preferred embodiment, i.e., a deposited conductor flexure structure which implements a gimb~l, it should be clear to those skilled in the art that the present invention may also be utilized in conjunction with, for example, an integrated gimbal loadbeam structure, or other conductive suspension members having proxim~tely mounted, deposited, or embedded conductors with or without ins~ tin~; overcoatings. Thus, it should be understood that the instant disclosure is not to be inlel~lcled as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
Claims (22)
1. An integrated flexure/conductor structure for supporting a read/write head adjacent to a storage medium and for electrically interconnecting the head to read/write circuitry, the flexure/conductor structure comprising:
a generally planar conductive flexure member including at least one void;
an electrical insulation layer disposed on the flexure member and at least partially overlaying the void; and electrically conductive traces disposed on the electrical insulation layer and at least partially overlaying the void.
a generally planar conductive flexure member including at least one void;
an electrical insulation layer disposed on the flexure member and at least partially overlaying the void; and electrically conductive traces disposed on the electrical insulation layer and at least partially overlaying the void.
2. The integrated flexure/conductor structure of claim 1 wherein impedance changes along the conductive traces near a boundary of the void are substantially continuous.
3. The integrated flexure/conductor structure of claim 2 wherein a cross sectional area of the void defined by upper and lower surfaces of the flexure member and a boundary of the void changes substantially continuous along the length of the flexure member.
4. An integrated flexure/conductor structure for supporting a read/write head adjacent to a storage medium and for electrically interconnecting the head to read/write circuitry, the flexure/conductor structure comprising:
a generally planar conductive flexure member having a boundary defining void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, and an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces.
a generally planar conductive flexure member having a boundary defining void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, and an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces.
5. The integrated flexure/conductor structure of claim 4 wherein the conductive traces comprise distinct read and write traces for conducting signals to and from the head.
6. The integrated flexure/conductor structure of claim 4 wherein the boundary is an interior boundary.
7. The integrated flexure/conductor structure of claim 4 wherein the boundary is an exterior boundary.
8. The integrated flexure/conductor structure of claim 6 or 7 wherein impedance changes along the conductive traces near the boundary are substantially continuous.
9. The integrated flexure/conductor structure of claim 4 wherein a cross sectional area of the void defined by upper and lower surfaces of the flexure member and the boundary changes substantially continuously along the length of the flexure member.
10. The integrated flexure/conductor structure of claim 4 wherein the flexure member has a thickness which tapers towards the boundary.
11. The integrated flexure/conductor structure of claim 4 wherein the interior boundary is undercut.
12. The integrated flexure/conductor structure of claim 4 wherein an orthogonal projection of the electrically conductive traces onto the planar conductive flexure member intersects the void.
13. The flexure/conductor structure of claim 12 wherein the flexure member is stainless steel.
14. The flexure/conductor structure of claim 13 wherein the electrically conductive traces comprise a material selected from the group consisting of aluminum, copper, and gold.
15. The flexure/conductor structure of claim 14 wherein the insulation layer is a flexible polymeric resinous material.
16. A laminated conductor and suspension structure for supporting a read/write head adjacent to a storage medium, the structure comprising:
a generally planar conductive loadbeam having a proximal actuator mounting end and a gimbaled head mounting region at a distal end for attaching the head, the loadbeam including a boundary defining a void;
electrically conductive traces disposed adjacent to the loadbeam and partially overlying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous; and an electrical insulation layer interposed between the loadbeam and the traces for electrically isolating the loadbeam from the traces.
a generally planar conductive loadbeam having a proximal actuator mounting end and a gimbaled head mounting region at a distal end for attaching the head, the loadbeam including a boundary defining a void;
electrically conductive traces disposed adjacent to the loadbeam and partially overlying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous; and an electrical insulation layer interposed between the loadbeam and the traces for electrically isolating the loadbeam from the traces.
17. An integrated-conductor suspension for supporting a read/write head adjacent to a storage medium and for electrically interconnecting the head to read/write circuitry, the suspension comprising:
a baseplate at a proximal actuator mounting end of the suspension;
a loadbeam connected to the baseplate;
a generally planar conductive flexure member attached to the loadbeam and having a boundary defining a void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous; and an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces.
a baseplate at a proximal actuator mounting end of the suspension;
a loadbeam connected to the baseplate;
a generally planar conductive flexure member attached to the loadbeam and having a boundary defining a void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous; and an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces.
18. An integrated-conductor head gimbal assembly for reading information from and writing information to a storage medium in a disk drive, the head gimbal assembly comprising:
a baseplate at a proximal mounting end of the head gimbal assembly;
a loadbeam connected to the baseplate;
a generally planar conductive flexure member attached to the loadbeam and having a boundary defining a void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous;
an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces; and a read/write head affixed to the flexure member at a distal end of the head gimbal assembly and electrically connected to the conductive traces.
a baseplate at a proximal mounting end of the head gimbal assembly;
a loadbeam connected to the baseplate;
a generally planar conductive flexure member attached to the loadbeam and having a boundary defining a void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous;
an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces; and a read/write head affixed to the flexure member at a distal end of the head gimbal assembly and electrically connected to the conductive traces.
19. A disk drive for storing and reproducing information, the disk drive comprising:
a disk drive base;
a storage disk rotatably mounted to the base;
motor means for rotating the disk;
a read/write head for reading information from and writing information to the storage disk;
signal processing means for communicating with head;
a movable actuator mounted to the base for selectively positioning the head relative to a radius of the storage disk; and an integrated-conductor suspension attached to the actuator for supporting the head adjacent to the storage disk and for electrically interconnecting the head to the signal processing means, the suspension comprising:
a baseplate at a proximal actuator mounting end of the suspension;
a loadbeam connected to the baseplate;
a generally planar conductive flexure member attached to the loadbeam and having a boundary defining a void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous;
an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces;
and wherein the head is mechanically affixed to the conductive flexure member at a distal end of the suspension and is electrically connected to the conductive traces and therethrough the signal processing means.
a disk drive base;
a storage disk rotatably mounted to the base;
motor means for rotating the disk;
a read/write head for reading information from and writing information to the storage disk;
signal processing means for communicating with head;
a movable actuator mounted to the base for selectively positioning the head relative to a radius of the storage disk; and an integrated-conductor suspension attached to the actuator for supporting the head adjacent to the storage disk and for electrically interconnecting the head to the signal processing means, the suspension comprising:
a baseplate at a proximal actuator mounting end of the suspension;
a loadbeam connected to the baseplate;
a generally planar conductive flexure member attached to the loadbeam and having a boundary defining a void;
electrically conductive traces disposed adjacent to the flexure member and at least partially overlaying the void, wherein impedance changes along the conductive traces near the boundary are substantially continuous;
an electrical insulation layer interposed between the flexure member and the traces for electrically isolating the flexure member from the traces;
and wherein the head is mechanically affixed to the conductive flexure member at a distal end of the suspension and is electrically connected to the conductive traces and therethrough the signal processing means.
20. The disk drive of claim 19 wherein the head includes separate read and write elements and the conductive traces comprise distinct read and write tracesfor conducting signals to and from the read and write elements, respectively.
21. The disk drive of claim 20 wherein the boundary is optimized with respect to the read traces.
22. The disk drive of claim 20 wherein the boundary is optimized with respect to the write traces.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US62143196A | 1996-03-25 | 1996-03-25 | |
| US08/621,431 | 1996-03-25 |
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| CA2221966A1 true CA2221966A1 (en) | 1997-10-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002221966A Abandoned CA2221966A1 (en) | 1996-03-25 | 1997-03-21 | Suspension with integrated conductor having controlled capacitance |
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| EP (1) | EP0900434A1 (en) |
| JP (1) | JPH11507465A (en) |
| KR (1) | KR19990021924A (en) |
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| AU (1) | AU2658797A (en) |
| CA (1) | CA2221966A1 (en) |
| WO (1) | WO1997036290A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5883758A (en) * | 1996-08-07 | 1999-03-16 | Hutchinson Technology Incorporated | Lead structure with stainless steel base for attachment to a suspension |
| US5982584A (en) * | 1996-12-19 | 1999-11-09 | Hutchinson Technology Incorporated | Integrated lead suspension flexure with serially arranged metal-backed and suspended insulator portions for hygrothermal compensation |
| JP3756650B2 (en) | 1996-12-19 | 2006-03-15 | ハッチンソン テクノロジー インコーポレーティッド | Integrated lead suspension flexure with balanced parallel leads for insulator layer temperature and humidity compensation |
| US6147839A (en) * | 1996-12-23 | 2000-11-14 | Hutchinson Technology, Inc. | Head suspension with outriggers extending across a spring region |
| US6612016B1 (en) | 1997-12-18 | 2003-09-02 | Hutchinson Technology Incorporated | Method of making integrated lead suspension flexure with balanced parallel leads for insulator layer hygrothermal compensation |
| US5924187A (en) | 1998-01-06 | 1999-07-20 | Hutchinson Technology Incorporated | Integrated lead head suspension assembly having an etched laminated load beam and flexure with deposited conductors |
| US6596184B1 (en) | 1999-02-15 | 2003-07-22 | International Business Machines Corporation | Non-homogeneous laminate materials for suspensions with conductor support blocks |
| US6576148B1 (en) * | 1999-02-22 | 2003-06-10 | International Business Machines Corporation | Non-homogeneous laminate material for suspension with electrostatic discharge shunting |
| US6585902B1 (en) * | 1999-02-27 | 2003-07-01 | International Business Machines Corporation | Non-homogeneous laminate material for suspension with vibration dampening |
| US6533950B1 (en) * | 1999-02-27 | 2003-03-18 | International Business Machines Corporation | Non-homogeneous laminate material for suspension with flexure motion limiter |
| US7382582B1 (en) | 2000-03-21 | 2008-06-03 | Magnecomp Corporation | Reduced cross talk in wireless suspensions |
| JP4277455B2 (en) * | 2001-02-27 | 2009-06-10 | Ｔｄｋ株式会社 | Head gimbal assembly |
| US6714385B1 (en) * | 2001-04-16 | 2004-03-30 | Hutchinson Technology Inc. | Apparatus and method for controlling common mode impedance in disk drive head suspensions |
| US7986494B2 (en) * | 2007-05-04 | 2011-07-26 | Hutchinson Technology Incorporated | Integrated lead head suspension with tapered trace spacing |
| JP5153686B2 (en) * | 2009-03-06 | 2013-02-27 | 日本発條株式会社 | Flexure for disk unit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4996623A (en) * | 1989-08-07 | 1991-02-26 | International Business Machines Corporation | Laminated suspension for a negative pressure slider in a data recording disk file |
| JPH0734547Y2 (en) * | 1989-12-07 | 1995-08-02 | アルプス電気株式会社 | Magnetic head support mechanism |
| EP0650156A1 (en) * | 1993-10-21 | 1995-04-26 | Seagate Technology International | Contact scheme for minimizing inductive pickup in magnetoresistive read heads |
| JP2814450B2 (en) * | 1994-03-31 | 1998-10-22 | インターナショナル・ビジネス・マシーンズ・コーポレイション | Head suspension assembly and method of manufacturing the same |
| JP3173714B2 (en) * | 1994-12-08 | 2001-06-04 | インターナショナル・ビジネス・マシーンズ・コーポレ−ション | Suspension system |
| US5608591A (en) * | 1995-06-09 | 1997-03-04 | International Business Machines Corporation | Integrated head-electronics interconnection suspension for a data recording disk drive |
-
1997
- 1997-03-21 AU AU26587/97A patent/AU2658797A/en not_active Abandoned
- 1997-03-21 KR KR1019970708399A patent/KR19990021924A/en not_active Application Discontinuation
- 1997-03-21 JP JP9534681A patent/JPH11507465A/en active Pending
- 1997-03-21 CA CA002221966A patent/CA2221966A1/en not_active Abandoned
- 1997-03-21 EP EP97918493A patent/EP0900434A1/en not_active Withdrawn
- 1997-03-21 CN CN97190246A patent/CN1185855A/en active Pending
- 1997-03-21 WO PCT/US1997/005346 patent/WO1997036290A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| KR19990021924A (en) | 1999-03-25 |
| EP0900434A1 (en) | 1999-03-10 |
| AU2658797A (en) | 1997-10-17 |
| CN1185855A (en) | 1998-06-24 |
| JPH11507465A (en) | 1999-06-29 |
| EP0900434A4 (en) | 1999-03-10 |
| WO1997036290A1 (en) | 1997-10-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |