Abstract:
Disk drives including head suspensions within dual stage actuation systems have improved electrical connectivity between electrical connection pads from flexible circuits as are applied to head suspension assemblies with piezoelectric microactuators as also provided to head suspension assemblies. A more robust electrical connection provides for better control of microactuator actuation for fine movements and positioning of magnetic read/write heads relative to disk data tracks as part of dual stage actuated suspension systems. Electrical connections utilize conductive epoxy for physically and electrically connecting electrically conductive trace connection pads with one or more surfaces of piezoelectric microactuators. Electrical connections include better conductivity by utilizing plural surface portions of electrical connection pads. The result is a more robust and predictable performance for high data resolution within disk drives.

Description:
PRIORITY CLAIM 
     The present non-provisional Application claims the benefit of commonly owned provisional Application having Ser. No. 62/053,356, filed on Sep. 22, 2014, which provisional Application is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to aspects of head suspension assemblies as are utilized for movably supporting a head within a disk drive, and in particular to head suspension assemblies that include a piezoelectric microactuator for fine head adjustability. The present invention is more particularly directed to electrical connections between such microactuators and conductor elements of such head suspension assemblies. 
     BACKGROUND OF THE INVENTION 
     Disk drives as data storage devices typically comprise a stack of rotatable disks to which data is written and read by way of magnetic heads that are movably supported with respect to surfaces of the disks by a like number of head suspension assemblies. One such head suspension assembly is typically movably supported relative to each disk surface so that a magnetic head can be selectively positioned relative to a data track of the disk surface, as such magnetic head is provided on an aerodynamically designed slider so as to fly closely above the disk surface while the disk is spinning. Each head suspension assembly is normally connected to an actuator arm for moving the head suspension and head over the disk surface for data writing and reading, and each actuator arm is connected to be driven by a voice coil drive device. Such an assembly allows each magnetic head to be independently controlled for positioning relative to specific data tracks of the disk surfaces. 
     The density of data tracks on such disk surfaces has been increasing in order to obtain greater data storage within a given disk surface area. Specifically, the data tracks themselves have become narrower and the radial spacing between tracks has decreased in order to increase disk data density. 
     In order to provide a second level of adjustability to a magnetic head as provided to a slider of a head suspension assembly and to obtain greater data resolution, microactuators have been developed. In general, a voice coil drive provides a first adjustability for course positioning of the magnetic head and a microactuator can then provide a fine adjustability for resolution of data tracks within high density disk drives. Such systems are considered dual-stage actuated suspension systems. 
     A common microactuator comprises one or more elements of piezoelectric crystal material such as lead zirconate titanate (PZT) as such elements are strategically provided at one or more locations along a head suspension assembly. A head suspension assembly typically comprises a base plate for connection with an actuator arm, a load beam including a base plate portion, a spring portion and a rigid region, and a flexure for supporting a slider with a magnetic read/write head. The interconnection of the flexure and load beam allow for pitch and roll movement of the aerodynamically designed slider relative to a spinning disk surface as the slider flies on an air bearing created by the spinning disk. 
     Microactuators have been developed to work on base plates, load beams and flexures by causing a distortion of material, typically stainless steel, by providing an electrical field across fixed elements of piezoelectric material. The controlled application of a voltage difference across a piezoelectric microactuator, such a PZT, causes the piezoelectric microactuator to expand or contract, in order to distort the base plate, load beam or flexure and thus controllably provide a fine movement of the slider and head with respect to a specific data track. Microactuators are sometimes provided in pairs for controlled deflections acting together by applying similar or opposite polarity electrical fields to the piezoelectric element pairs depending upon the location and arrangement of the piezoelectric element pairs. 
     In order to controllably actuate such piezoelectric microactuators, positive and negative electrical connections are provided to each piezoelectric microactuator. Conductors as are typically provided along head suspension assemblies extending to the head for read/write functionality and for providing voltage across the piezoelectric microactuators of a dual stage actuated head suspension. Such conductors can be provided as wires or as traces of flex type circuits that can be formed integral with or attached along the load beam of a head suspension assembly. Utilizing conductive traces, connection pads are typically provided at the end of the conductive traces for connection with positive and negative voltage surfaces of each piezoelectric microactuator. 
     Conductive traces themselves are usually comprised as a laminate type structure including a stainless steel structural or support layer with an insulator layer between the stainless steel and any number of conductive traces as may be formed of any electrically conductive material, such a copper. The connection pads are made by creating a circular pad of the stainless steel, insulating material and the copper layer, followed by removing (such as by etching) an area of the stainless steel and insulating material from below the copper layer to provide access to the copper layer through the other layers of the connection pad. Such connection pads are also known to be provided as gold plated copper pads. 
     In order to electrically and physically connect the electrical connection pad to a surface of the piezoelectric microactuator, which surface also may be gold plated, conductive epoxy is known to be utilized. Conductive epoxy can comprise a conventional epoxy resin that is impregnated with silver flakes and/or particles of sufficient silver density within the resin to render the epoxy capable of providing an electrical connection through the epoxy resin. In addition to including sufficient silver particle density for electrical conductance though the epoxy connection, it is also been determined that good electrical connection between the gold plated copper pad surface and the silver particles of the epoxy is needed. Intermittent electrical connections can result from faulty or insufficient electrical connection at this electrical pad to epoxy interface. 
     Faulty electrical connection between the connection pad of the flexible circuit and the surface of the piezoelectric microactuator can result from separation of the silver particles at the interface of the conductive epoxy and the gold plated copper surface of the connection pad. This situation is referred to as a resin rich formation at the interface of the gold plated surface of the connection pad with the conductive epoxy. The formation of resin rich zones along the interface with the surface of the connection pad reduces conductivity from the connection pad to the conductive epoxy. Resin rich zones are believed to result sometimes during the curing process of the conductive epoxy due to material differences between the copper connection pad and the epoxy. For example, thermal expansion of one material, such as the copper, during curing can affect the interface as well as material shrinkage of a material, such as the epoxy, during its curing. Other factors can include physical conditions, such as vibrations or otherwise, as may affect this interface during the epoxy curing process. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention overcomes the disadvantages and shortcomings of the prior art disk drive technology by improving the electrical connectivity between electrical connection pads from flexible circuits as are applied to head suspension assemblies with piezoelectric microactuators as also provided to head suspension assemblies. A more robust electrical connection provides for better control of microactuator actuation for fine movements and positioning of magnetic read/write heads relative to disk data tracks as part of dual stage actuated suspension systems. 
     Electrical connections of the present invention utilize conductive epoxy for physically and electrically connecting electrically conductive trace connection pads with one or more surfaces of piezoelectric microactuators. The result is a more robust and predictable performance for high data resolution within disk drives. 
     In one aspect of the present invention, a head suspension for supporting a head within a disk drive can comprise a load beam including a base portion for connection to an actuator for moving the load beam relative to a disk and a flexure for connection with a head and to permit movement of the head for orientation thereof relative to a surface of the disk; a microactuator operatively provided and coupled to the load beam for providing fine movements to the load beam and head relative to the disk, the microactuator including a surface for connection with an electrical source to effect fine movement of the load beam; and a flexible circuit provided to extend along the load beam and comprising a plurality of electrical traces along an insulator layer, at least one trace including a connection pad positioned to extend over the surface connection of the microactuator for connection with a controllable power source for selective actuation of the microactuator, wherein the connection pad comprises a conductive first surface that is accessible by an opening within the insulator layer, a conductive second surface, and at least an edge portion between the first and second surfaces, and the connection pad is adhered to the surface connection of the microactuator by a conductive epoxy that is adhered to the surface connection of the microactuator and to the first and second conductive surfaces and the edge portion of the connection pad. 
     Preferably, the flexible circuit includes a stainless steel support layer on the opposite side of the insulator layer than the electrical traces, wherein the stainless steel support layer also includes an opening to provide accessibility to the connection pad. The connection pad can be offset from the at least one trace so as to be at least partially positioned within the opening of the insulator layer. 
     In one case, the connection pad can include an opening provided through the connection pad that defines the edge portion that is adhered with the conductive epoxy. The connection pad can have plural openings defining plural edge portions with the plural edge portions and a portion of the second surface of the connection pad between the openings being adhered with the conductive epoxy. The plural openings of the connection pad can further be symmetrically arranged. 
     In another case, the connection pad can comprise an open edge portion that provides the edge portion that is adhered with the conductive epoxy along with portions of the first and second surfaces of the connection pad adjacent to the edge portion. Such a connection pad can include plural open edge portions to provide plural edge portions that are adhered with the conductive epoxy along with portions of the first and second surfaces of the connection pad adjacent to each of the edge portions. Moreover, the plural open edge portions can be created by tabs that extend from the connection pad. 
     According to another aspect of the present invention, a flexible circuit can be provided onto at least one surface of a head suspension and for providing data signals and a power supply to a microactuator of the head suspension, wherein the flexible circuit comprises a plurality of electrical traces provided to extend along an insulator layer, at least one trace for connection with a controllable power source for selective actuation of a microactuator the at least one trace including a connection pad positioned for extension over a surface connection of the microactuator, wherein the connection pad comprises a conductive first surface that is accessible by an opening within the insulator layer, a conductive second surface, and at least an edge portion between the first and second surfaces so that the connection pad can be adhered to the surface connection of the microactuator by a conductive epoxy with the conductive epoxy to be adhered to the surface connection of the microactuator and to the first and second conductive surfaces and the edge portion of the connection pad. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Other important objects and advantages of the present invention will be apparent from the following detailed description of the invention taken in connection with the accompanying drawings in which; 
         FIG. 1  is a perspective view of a head stack assembly including plural stacked actuator arms with each arm having a head suspension assembly in accordance with the present invention; 
         FIG. 2  is a perspective view of a head suspension assembly of the present invention including a pair of microactuators arranged in the baseplate region of the head suspension assembly and including electrical connection components of the present invention; 
         FIG. 3  is a perspective view of a head suspension assembly of the present invention as attached to an actuator arm at the baseplate; 
         FIG. 4  is a partial cross-sectional view of the connection between a baseplate of a head suspension assembly and an actuator arm; 
         FIG. 5  is partial cross-sectional view of a baseplate mounted microactuator in accordance with an aspect of the present invention including electrical connections to two sides of a piezoelectric microactuator including the provision of conductive adhesive; 
         FIG. 6  is a partial bottom side view of the head suspension assembly of  FIG. 2  showing a flexible circuit routed over the portion of the head suspension assembly and specifically routed to termination points to extend over and connect with surface points of a surface of the plural microactuators; 
         FIG. 7  is a perspective view of an electrical trace portion of a flexible circuit terminating at a conventional electrical connection pad and as adhered to a surface of a piezoelectric microactuator; 
         FIG. 8  is a cross-sectional view of the connection pad of  FIG. 7  showing the construction of the connection pad as including a conductor, an insulating layer, and a support layer where the conductor can be accessed through the insulating layer and the support layer; 
         FIG. 9  is a view similar to that of  FIG. 8 , but with conductive epoxy provided between the connection pad and the surface of the microactuator; 
         FIG. 10  is a perspective view of an electrical trace portion of a flexible circuit terminating at a first embodiment of an electrical connection pad in accordance with the present invention and as adhered to a surface of a piezoelectric microactuator; 
         FIG. 11  is a cross-sectional view of the connection pad of  FIG. 10  showing the construction of the connection pad as including a conductor, an insulating layer, and a support layer where the conductor can be accessed through the insulating layer and the support layer; 
         FIG. 12  is a view similar to that of  FIG. 11 , but with conductive epoxy provided between the connection pad and the surface of the microactuator, wherein the conductive epoxy is further adhered first and second surfaces of the conductor and at least an edge portion between the first and second surfaces of the conductor; 
         FIG. 13  is a perspective view of an electrical trace portion of a flexible circuit terminating at a second embodiment of an electrical connection pad in accordance with the present invention and as adhered to a surface of a piezoelectric microactuator; 
         FIG. 14  is a cross-sectional view of the connection pad of  FIG. 13  showing the construction of the connection pad as including a conductor, an insulating layer, and a support layer where the conductor can be accessed through the insulating layer and the support layer; 
         FIG. 15  is a view similar to that of  FIG. 14 , but with conductive epoxy provided between the connection pad and the surface of the microactuator, wherein the conductive epoxy is further adhered first and second surfaces of the conductor and at least an edge portion between the first and second surfaces of the conductor; 
         FIG. 16  is a perspective view of an electrical trace portion of a flexible circuit terminating at a third embodiment of an electrical connection pad in accordance with the present invention and as adhered to a surface of a piezoelectric microactuator; 
         FIG. 17  is a cross-sectional view of the connection pad of  FIG. 16  showing the construction of the connection pad as including a conductor, an insulating layer, and a support layer where the conductor can be accessed through the insulating layer and the support layer; and 
         FIG. 18  is a view similar to that of  FIG. 17 , but with conductive epoxy provided between the connection pad and the surface of the microactuator, wherein the conductive epoxy is further adhered first and second surfaces of the conductor and at least an edge portion between the first and second surfaces of the conductor. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The foregoing specific embodiments of the present invention as set forth in the specification herein are for illustrative purposes only. Various deviations and modifications may be made within the spirit and scope of the invention without departing from the main theme thereof. 
       FIG. 1  illustrates a perspective view of exemplary components of a data storage device including a head stack assembly  100  and media  102 . In one embodiment, magnetic media  102  stores information as domains in a plurality of circular, concentric data tracks on data disks as such disks are conventionally mountable to a spindle motor assembly (not shown) that can rotate media  102  and cause its data surfaces to pass under respective bearing slider surfaces. As illustrated, each surface of media  102  has an associated slider  104 , each of which slider  104  carries a magnetic head comprising read and write transducers that communicate with the data tracks of the surfaces of media  102 . 
     Sliders  104  are each supported by a head suspension assembly  108 , which are in turn attached to actuator arms  112  of an actuator mechanism  116  to form the head stack assembly  100 . Actuator mechanism  116  can be rotated about a shaft  118  by a voice coil drive  120 , which can be conventionally controlled by servo control circuitry. Voice coil drive  120  can rotate actuator mechanism  116  in either rotary direction for controllably positioning the head suspension assemblies  108  over the surfaces of the spinning disks and thus the heads of the sliders  104  relative to desired data tracks between inner diameters  122  and outer diameters  124  of media  102 . As also well known, the sliders  104  are themselves aerodynamically designed to fly on an air bearing that is created adjacent to each disk surface during disk rotation. 
       FIG. 2  illustrates an enlarged perspective view of exemplary head suspension assembly  108  in accordance with aspects of the present invention.  FIG. 3  is a partial perspective view of the head stack assembly  100  illustrated in  FIG. 1  including head suspension assembly  108  as illustrated in  FIG. 2  and as connected with an actuator arm  112  for movement relative to a disk surface. Head suspension assembly  108  includes a load beam  126 , a flexure  127 , a mount or base plate  132 , and a slider  104 . The load beam itself comprises a base portion that is connected with the base plate  132 , such as by laser welding, a spring or hinge region  131 , and a rigid region leading from the spring region to the tip of the head suspension assembly  108 . Load beam  126  supports the slider  104  (not seen in  FIGS. 2-3 ) carrying transducers via the separately formed and attached flexure  127 . Alternatively, an integrated gimbal can be utilized instead of the flexure  127 , as well known. For example, a gimbal is typically integrated into load beam  126 , while a flexure is a separate component that can be laser welded to load beam  126  and provides a slider mounting portion that is pivotable about a dimple as provided from an end portion of the rigid region of the load beam  126 , such as illustrated. Regardless of type, a gimbal or a flexure  127  provides a movable slider mounting pad to which head or slider  104  is attached so that the slider can move at least in pitch and roll directions in response to variations while flying relative to a disk surface. 
     The spring or hinge region  131  provides load beam  126  with a preload force that acts against the lift force action of the aerodynamic slider as it flies relative to a disk surface. The preload force urges the slider  104  towards the surface of a medium during flight to maintain a desired fly height. In some embodiments, hinge  131  is a separate component from load beam  126  and can be connected to load beam  126  by laser welding. In other embodiments, hinge  131  is integrated with and contiguous with load beam  126  as a single part. Mount plate or baseplate  132  provides an attachment structure for coupling actuator arm  112  to a head suspension assembly  108 . In one embodiment, baseplate  132  is laser welded to a base plate portion of the load beam  126 . As illustrated in  FIG. 2 , the attachment structure can be a boss tower  136  of the base plate  132  that is configured to insert into aperture  138  ( FIG. 4 ) of an actuator arm  112  and undergo a swaging process, such as ball swaging, to couple actuator arm  112  to a head suspension assembly  108 . Boss tower  136  is preferably integrally formed with baseplate  132  and is made of the same material. For example, baseplate  132  can be made of a ferrite, such as stainless steel, aluminum, engineered plastic and the like. 
     Head suspension assembly  108  also includes a pair of microactuators  140  and  141 . While voice coil motor  120  rotates actuator mechanism  116  to position sliders  104  relative to desired data tracks between inner diameters  122  and outer diameters  124  of media  102  (see  FIG. 1 ), microactuators  140  and  141  provide head suspension assembly  108  with fine or precision-type positioning of sliders  104  relative to desired data tracks between inner diameters  122  and outer diameters  124 . In one embodiment, microactuators  140  and  141  are piezoelectric actuators. Piezoelectric actuators convert an electric signal into controlled physical displacements and, as such, piezoelectric actuators are made of fragile materials. Exemplary materials include ceramics and metal electrode foils. A common microactuator material and design includes one or more elements of piezoelectric crystal material such as lead zirconate titanate (PZT) as such elements are strategically provided at one or more locations along a head suspension assembly. Microactuators have been developed to work on base plates, load beams and flexures by causing a distortion of material, typically stainless steel of the load beam or a flexure, by providing an electrical field across fixed elements of piezoelectric material. The controlled application of a voltage difference across a piezoelectric microactuator, such a PZT, causes the piezoelectric microactuator to expand or contract, in order to distort the base plate, load beam or flexure and thus controllably provide a fine movement of the slider and head with respect to a specific data track. In accordance with the exemplary head suspension assembly of  FIGS. 1-4 , microactuators  140  and  141  are provided as a pair in order to controllably distort the head suspension assembly  108  within its base plate region. In this case, the microactuators  140  and  141  are provided as a pair for controlled deflections acting together by applying similar or opposite polarity electrical fields to the piezoelectric element pairs depending upon the location and arrangement of the piezoelectric element pairs. 
       FIG. 4  is an enlarged section view representative of a portion of the head stack assembly  100 . More specifically,  FIG. 4  illustrates a section view of a portion of actuator arm  112 , baseplate  132  and a base plate portion  128  of load beam  126  before boss tower  136  is swaged to aperture  138 . As illustrated in  FIG. 4 , the z-height  170  of the head stack assembly  100  includes an overall height or thickness of actuator arm  112 , baseplate  132  and load beam  126 . 
     As illustrated in  FIG. 2 , microactuators  140  and  141  are located within inlets  143  that are provided within the profile of the baseplate  132  and have heights that are substantially the same or less than the height of baseplate  132 . In this way, the rigid material of baseplate  132  provides protection to the fragile material of microactuators  140  and  141 . The microactuators  140  and  141  are each preferably supported in position by edges portions  144  of the base plate portion of the load beam  126  adjacent to the inlets  143  of the baseplate  132 . Specifically, edge portions  144  preferably extend within the inlets  143  along at least two sides so as to provide a supporting ledge structure for the microactuators  140  and  141 . More preferably, the edges  144  provide a surface to bond or adhere edges of the microactuators  140  and  141  so that as they are extended or retracted, they provide a predictable and controllable movement to the head suspensions assembly. In the illustrated embodiment, extension of one of the microactuators  140  and  141  and contraction of the other of the microactuators  140  and  141  by application of opposite electrical fields to each of the microactuators  140  and  141  causes a deflection or twisting of the base plate portion  128  of the load beam  126 , thus controllably moving the rigid region  129  of the load beam  126  and thus the flexure  127  and slider  104 . A reverse application of electrical field to each of the microactuators  140  and  141  will cause an opposite but similar deflection or twisting of the head suspension assembly. 
     In order to bond or adhere the microactuators  140  and  141  to the edge portions  144  at each side of the baseplate  132  within the inlets  143 , an epoxy adhesive is preferably used as shown in  FIG. 5  at  145  and  146 . Any type of adhesive or bonding technique is contemplated provided that the connection is preferably a non-conductive connection between the piezoelectric material and the typically conductive material of the baseplate  132  and load beam  126 . That is to say, that it is preferable that the microactuators  140  and  141  be supported and fixed to the base plate  132  and load beam  126  in an electrically non-conductive manner along at least two sides so as to effectively provide deflection to the load beam upon expansion or contraction of each microactuator  140  and  141 . 
     Electrical conductors are provided along the head suspension assembly by way of one or more flexible circuits  147  as may comprise any number of conductors as are needed for electrical connection with the read and write heads of the slider  104  as well as for microactuator control as discussed below. Flexible circuits are well known, per se, and as provided and bonded along head suspension assemblies for electrical connection purposes. As shown in  FIG. 2 , a flexible circuit  147  runs along the load beam  126  from the baseplate region  128  all the way to near the end of the rigid region  129  to electrically connect with the read/write head of the slider  104 . Typically, certain leads or traces of the flexible circuit also run alongside each side of the flexure to extend to the slider  104  for balance. 
     A flexible circuit can comprise any number of leads or traces that are usually comprised of conductive metal, such as copper, and are commonly supported together on a substrate of semi-rigid material such a stainless steel with a layer of insulator material in between, such as comprising polyimide. Electrical connections with the slider  104  can be conventionally done with wires or direct connections as known. 
     To controllably provide such expansion and contraction of the piezoelectric material of the microactuators  140  and  141 , an electrical field is applied across the thickness of each of the microactuators  140  and  141 . To do this, a first electrical connection is preferably provided to one surface of each microactuator  140  and  141  and a second electrical connection is preferably provided to a second surface of each microactuator  140  and  141 . Specifically, a positive electrical connection should be provided to one surface and a negative electrical connection provided to the other surface. 
     As shown in  FIG. 5 , a first electrical connection is provided by way of a deposit of conductive epoxy  152  provided between a first surface  150  of the microactuator  140  and one or more surface portions of the baseplate  132 . The conductive epoxy is shown as deposited along a top surface edge portion of the microactuator  140  connecting with a vertical side edge and a top surface of the baseplate  132 . 
     A second electrical connection is provided to a second surface  151  of the microactuator  140 . As shown in  FIG. 6 , electrical trace portions  148  extend from the flexible circuit  147  as routed along the bottom surface (based on the orientation of  FIG. 2 ) so as to be positioned to extend over a surface connection portion of the second surface  151  of the microactuator  140 . In particular, the trace portions  148  terminate at connection pads  155  that are connected with the surface connection of the second surface  151  of microactuator  140  by way of second deposit of conductive epoxy  153 . The connection pads  155  provide a conductor surface for connection with the surface connection of the second microactuator surface  151  by way of the conductive epoxy  153 , as further described below. With the traces  148  electrically connected at their other end with a selectable power source (not shown), electrical fields of opposite polarities can be controllable and selectively created across the microactuator  140  for causing microactuator expansion and contraction, as known. 
       FIGS. 7-9  show a conventional connection pad  255  as a termination point of a trace  248  with the connection pad  255  comprising a copper conductor  256 , a polyimide insulating layer  257 , and a stainless steel support layer  258 . The insulating layer  257  and the support layer  258  are typically etched or otherwise formed in the shape of a ring, with the support layer ring larger than the insulating layer ring. Such a construction allows access to the copper conductor  256  from its bottom side (i.e. from the stainless steel support layer side) for electrical connection with a surface of a microactuator  140 . The conductor is shown as also having a dished or recessed central portion for improved access to the conductor surface at a same level as a lower insulating layer surface. As shown in  FIG. 9 , such a construction allows for conductive epoxy  260  to adhere to the central region of the conductor  256 , an annular surface portion of the insulating layer  257 , and the annular lower surface of the stainless steel support layer  258 . As such, electrical connection is provided from the conductor  256  to a surface connection point of a microactuator surface. 
     It is an object of the present invention to improve the electrical connectivity between such a conductor and the conductive epoxy. As discussed above in the Background section, various circumstances particular during the curing stage of the conductive epoxy can lead to resin rich regions along the interface of the copper conductor layer and the conductive epoxy. Such resin rich regions can be deficient in the mixture concentration of silver particles or flakes and thus have reduced conductivity in those regions. Insufficient conductivity can thus affect microactuator performance. 
       FIGS. 10-12  show a first embodiment of a connection pad  355  in accordance with the present invention that provides for an improved electrical connection at the interface of the trace conductor  356  with the conductive epoxy  360 . In accordance with the present invention, it is desirable to improve this electrical connection by at least partially encapsulating a portion of the conductor  356  to increase the area of the interface between the conductor  356  and the conductive epoxy  360  and to increase such interface along at least an edge portion and a second surface portion of the conductor for improved silver particle or flake connectivity with the conductor  356 . Moreover, any force or activity caused within the dynamics of the adherence or curing process will advantageously apply to both sides of a conductor portion surrounded by the conductive adhesive. For example, a mechanical action during a curing process of the conductive adhesive tending to pull adhesive away on one side of a conductor portion would tend to urge adhesive on the other side of the conductor portion toward the conductor. 
     In this embodiment, the conductor  356  also terminates as a circular connection pad  355  that is preferably provided with a dished or recessed central portion. The recessed central portion is not needed, but can be provided to create a volume where adhesive can flow to at least partially surround or encapsulate at least a portion of the conductor  356  of the connection pad  355 . In order to provide improved conductive epoxy  360  access to first and second oppositely facing surfaces of the conductor and at least one edge portion between the first and second surfaces, an opening  361  is provided through the conductor, preferably as shown at a central location. The opening  361  can be offset or otherwise within the shape of the connection pad  355 . This opening  361  allows a flow of the conductive epoxy prior to curing from a first or bottom surface of the conductor  356  through the opening  361  and at least partially over a second or top surface of the conductor  356 . Preferably, the conductive epoxy  360  is controlled to flow and substantially fill the recessed central region of the conductor  356 . Then, the conductive epoxy is permitted to cure while in contact with both of the first and second surfaces and the circular edge defining the opening  361  to improve conductivity along the interface. The result, as shown in  FIG. 12  is an encapsulated portion  365  that in this embodiment comprises an annular portion of the conductor  356  surrounding the opening  361 . It is contemplated that the opening can be of any shape or size and that the connection pad shapes, sizes and orientation to one another can be modified in accordance with the present invention. 
       FIGS. 13-15  show another embodiment of a connection pad  455  in accordance with the present invention that provides for an improved electrical connection at the interface of the trace conductor  456  with the conductive epoxy  460 . Like the embodiment of  FIGS. 10-12 , a trace  448  terminates at conductor  456  that is preferably provided with a dished or recessed central portion. The insulating layer  457  terminates as a ring surrounding the dished central portion of the conductor  456  and the support layer  458  terminates as a ring larger than that of the insulating layer  457 . 
     A plurality of openings  461  are shown as provided through the central dished or recessed conductor  456  leaving an encapsulation portion  466  between the plural openings  461 . As shown in  FIG. 15 , these openings  461  allow a flow of the conductive epoxy prior to curing from a first or bottom surface of the conductor  456  through the plural openings  461  and at least partially over a second or top surface of the conductor  456 . Preferably, the conductive epoxy  460  is controlled to flow and substantially fill the recessed central region of the conductor  456 . Then the epoxy is permitted to cure while in contact with both the first and second surfaces and the edges defining the openings to improve conductivity along the interface. The result of this embodiment, as shown in  FIG. 15  is an encapsulated portion  466  between the openings  461  and an encapsulated annular portion  465  similar to portion  365  described above. As above, it is contemplated that any number of openings can be provided and that the openings can be of any shape or size. Also, the connection pad shapes, sizes and orientation to one another can be modified in accordance with the present invention. 
       FIGS. 16-18  show yet another embodiment of a connection pad  555  in accordance with the present invention that also provides for an improved electrical connection at the interface of the trace conductor  556  with the conductive epoxy  560 . A trace  548  terminates at conductor  556  that is also preferably provided with a dished or recessed central portion. The insulating layer  557  terminates as a ring surrounding the dished central portion of the conductor  556  and the support layer  558  terminates as a ring larger than that of the insulating layer  557 . 
     This embodiment differs from those of  FIGS. 10-12 and 13-15  in that an encapsulation portion  565  is provided external or outside to the footprint of the connection pad  555 . In the embodiments above, encapsulation portions  365 ,  465  and  466  have each been internal or inside with respect to the footprint of the connection pads  355  and  455 . In this case, the encapsulation portion  565  is extended by an arm portion  566  so as to be positioned beyond the annular ring terminations of the insulating layer  557  and the support layer  558 . As also shown, the insulating layer  557  is preferably also extended partially along the arm portion  566  to provide adequate insulation over the support layer material. As shown in  FIG. 18 , a flow of the conductive epoxy  560  prior to curing can be controlled from a first or bottom surface of the conductor  556  along and around the encapsulation portion  565  and at least partially over a second or top surface of the conductor  556 . Then the epoxy  560  is permitted to cure while in contact with both the first and second surfaces and the edges defining the encapsulation portion  565  of the arm  566  to improve conductivity along the interface. The result of this embodiment, as shown in  FIG. 18  is an encapsulated portion  565  at the end of the arm portion  566 . It is contemplated that any number of such arm portions or extension of any size and shape can be provided. The connection pad shapes, sizes and orientation to one another can be modified in accordance with the present invention. 
     Moreover, it is contemplated that designs of the present invention can include both internal and external encapsulation designs. For example, a conductor termination can include one or more opening and one or more extension portions for providing the ability to improve conductivity both internal to and external to the footprint and design of the connection pad. 
     Conductive epoxy itself is well known and commercially available. Typically, silver is utilized in particle or flake form within the epoxy resin material of sufficient mix concentration so that electrical conductivity is achieved through the epoxy resin within desired resistivity limits. It is further contemplated that other adhesives than epoxies can be utilized in accordance with the aspects of the present invention. Any adhesive should have sufficient cohesive properties with the materials of the conductor material and with the microactuator material and should be able to be compatible with and mixable with sufficient conductive material to create a sufficient electrical connection through its volume as applied. Conductive materials of any composition are also contemplated to be provided with such adhesive as having the material properties to do so. Further conductive adhesives wherein the adhesive itself is sufficiently electrically conductive are also contemplate, as such adhesives may not require additional conductive particles, flakes or the like to be mixed within the adhesive composition.