Abstract:
An electrical interconnect and a method of making an electrical interconnect in which a conductor has been substantially plated with a first protective metal shell, such as nickel, and a second outer metal shell, such as gold, before a covercoat has been applied. Such an electrical interconnect can be characterized as having an even-thickness outer shell on both its terminal pads and underneath the covercoat adjacent to the terminal pads, without overhangs or gaps near the bottom of the covercoat caused by surface etching during production.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of disk drive storage devices. More particularly, this invention relates to a corrosion resistant electrical interconnect for a disk drive suspension and a method of producing such an electrical interconnect. 
     2. Description of Related Art 
     A disk drive generally uses several spinning storage medium (e.g. disks) to store data. Several read/write heads are positioned in close proximity to the disks by suspension assemblies. In a hard disk drive, a suspension assembly commonly refers to the combination of a slider/head, containing the read-write circuitry affixed to the distal end of the suspension. The suspension supports the slider as well as an electrical interconnect. The electrical interconnect connects the read/write head, located on the slider at the end of the head suspension over a disk, to disk drive circuits at the proximal end of the head suspension. The electrical interconnect carries electrical signals from the read/write head that are read from the disk across the head suspension to disk drive circuitry. It also carries electrical signals to be written to the disk from the disk drive circuitry across the head suspension to the read/write head. 
     An electrical interconnect can be created by an additive circuit laying process where layers are essentially added to an insulating base. 
     An insulating base is sometimes called an insulating or insulative substrate, film, or base layer. The purpose of the insulating base is typically to provide a supporting surface, with low electrical conductivity, upon which circuitry can be added. It is common to call the side of the insulating base upon which circuitry can be added the “top” of the insulating base, and the opposing side the “bottom.” 
     An insulating base can be a single insulating layer or multiple layers. An insulating base can have multiple layers of insulating and non-insulating layers as long as an insulating layer is on the top. A non-insulating layer is typically conductive. A conductive layer is sometimes called a conductor layer, conductive substrate, or metal substrate, and can include a thin metal foil or a supporting metal plate. Non-insulating layers within an insulating base may include a layer or multiple layers which support the top insulating layer. If a layer supports the top insulating layer, then the supporting layer is sometimes called a supporting substrate. For example, a supporting substrate can be part of a stainless steel load beam. 
     In an additive process, a relatively thin seed layer is typically added to the top of an insulating base. A seed layer is sometimes called a thin metal film. A seed layer is added to the insulating base by vacuum deposition, such as sputtering. Typically, the seed layer is deposited over the entire top side of the insulating base so as to form a continuous sheet. The seed layer can be a single stratum of material, or it can be multiple stratums of material formed sequentially. The top stratum of a seed layer is typically the same material as will be used for the conductor, discussed below. 
     On top of the seed layer is typically added a plating resist pattern. Plating resist material, which makes up the plating resist pattern, prevents metal from plating on portions of the seed layer which it covers and provides a vertical profile to which the metal will conform. The plating resist pattern can be applied in a reverse pattern with respect to the final wired circuit pattern. The thickness of the plating resist is chosen as at least the thickness of the metal to be plated. 
     “Applying” a layer can include any method which forms a patterned layer on a surface. Applying can include the multiple steps of spreading a photosensitive resin on a surface, exposing the resin to a pattern of light or other electromagnetic radiation, developing the pattern (or reverse pattern), washing away the undeveloped resin, and baking the resin. Applying can also include the use of a dry film resist. 
     The insulating base, seed layer, and plating resist pattern are then subjected to a plating process in which a conductor is plated. Such plating is sometimes called “conductor-plating.” A conductor is any material, such as copper metal, which is suitable for carrying a majority of current in an electrical interconnect. The plated conductor is formed on the exposed seed layer, in a reversal pattern with respect to the plating resist pattern on the seed layer. The pattern that the conductor conforms to is sometimes called a wiring pattern or circuit pattern. 
     The term, “plating,” is a general surface-covering technique in which a metal is deposited onto a conductive surface. The term most often refers to electroplating or electroless plating, both typically performed in a liquid bath. 
     The insulating substrate, seed layer, plating resist pattern, and plated conductor arrayed in a wired circuit pattern are sometimes collectively called an inchoate electrical interconnect. The inchoate electrical interconnect is considered a workpiece. 
     The term, “workpiece,” can refer to any starting piece or any product of an intermediate process. A workpiece includes material or parts of a workpiece that will remain in a final product or be removed in later processes. A workpiece can be rigid or non-rigid. A workpiece is usually self-cohesive, but can include evanescent matter that will easily fall off, drip off, evaporate, or sublimate, such as a liquid on a surface that has not yet evaporated. 
     After conductor-plating, an optional layer of protective metal can be plated over the conductor. This is sometimes called “protective-metal-plating.” Protective metal can be any metal suited to protect a conductor underneath, such as nickel or a nickel-phosphorous alloy. Nickel is a suitable substance because nickel exposed to air forms a nickel-oxide layer which can protect an underlying conductor, such as copper, from oxidizing. The plating of nickel in disk drive head suspensions is often in the form of electroless nickel plating. Electroless nickel plating is commonly done at very high temperature. 
     The plating resist pattern can then be stripped from the workpiece, and portions of the seed layer which had underlain the plating resist pattern can be etched away. The etching of the seed layer, which typically covers the entire top side of the insulating base, can electrically isolate various conductor features, such as different wire traces. 
     A covercoat is then applied as an insulator to protect the conductor and prevent accidental shorts. A covercoat is sometimes cured (imidized) at elevated temperatures, such as 250° C. or more. The covercoat is rarely applied to terminal pads or other areas which will remain exposed. 
     Surfaces of the conductor which are still exposed, such as on terminal pads, can be coated with various metals for corrosion resistance, scratch protection, bonding facilitation, and other desirable properties. These metal coatings are often plated in what are sometimes called secondary plating operations. 
     Before secondary plating operations commence, the exposed surfaces are usually cleaned in a pretreatment process and activated with a weak acid etch. Etching at this stage in a process is sometimes called “surface-etching.” If an optional protective metal was plated over the conductor, then it has probably started to oxidize. Nickel-oxide forms more quickly at elevated temperatures. The optional protective metal is peeled away or etched with a strong acid etch from the terminal pads in preparation for subsequent plating. 
     After pretreatment and surface-etching, the exposed conductor surfaces are plated with a first layer of protective metal. This metal can be the same type used for the optional protective layer. To improve bonding and contact characteristics, terminal pads are sometimes plated with a second layer of contact metal, such as gold. This is sometimes called “contact-metal-plating.” Contact metal can be any metal used to improve the connection characteristics of a terminal contact, such as but not limited to gold or silver. Gold is often used as a contact metal because it is corrosion resistant, electrically conductive, ductile, and relatively nontoxic. Nickel is often used as the protective metal between a copper conductor and a gold layer because a nickel layer can reduce the occurrence of copper diffusing into gold and discoloring the gold surface. 
     Hard drive reliability is a critical part of hard drive qualification, and it is more important to hard drive applications requiring severe environmental conditions and a longer lifetime. One of the key drive reliability tests in some applications is hard disk drive corrosion testing, where components are tested at 85° C. at 85% relative humidity for anywhere from 24 hours up to 504 hours. 
     Examples of the manufacturing steps outlined above are disclosed in U.S. Pat. No. 6,399,899 issued to Ohkawa et al. in FIGS. 5-8 and U.S. Pat. No. 7,129,418 issued to Aonuma et al. in FIGS. 2-3. 
     There is a need for an improved electrical interconnect for a disk drive head suspension. Specifically, there is a need for an electrical interconnect which can better resist corrosion, particularly around its terminal pads, and a method for producing such an electrical interconnect. 
     SUMMARY OF THE INVENTION 
     The present invention is an electrical interconnect for a disk drive head suspension and a method of producing such an electrical interconnect. The present invention also includes a disk drive head suspension and a hard disk drive incorporating the electrical interconnect. 
     A problem encountered in the prior art is that surface-etching can remove metal from areas next to those being surface-etched, underneath a coverlayer. This can especially be a problem on the fringes of terminal pads. The fringes of terminal pads are considered the boundary area between the insulating covercoated portion of a terminal pad region and the exposed portion of the terminal pad itself. 
     The problem is illustrated in  FIGS. 7A-7D .  FIG. 7A  shows a terminal pad  725  of an electrical interconnect with a supporting substrate  741 , insulating base  743 , seed layer  745 , conductor  749 , and covercoat  755 . Terminal pad  725  has a fringe  726 . In  FIG. 7B , a surface etch solution partially etches conductor  749  at terminal pad  725  and also partially underneath covercoat  755 . A gap  728  results from the surface-etching. Gap  728  is sometimes called an overhang. Gap  728  can trap small dust particles or other debris as illustrated in  FIG. 7C .  FIG. 7D  shows secondary plating operations which can embed the debris. 
     The problem can be worse if an optional protective metal shell, such as a nickel shell, is plated over a conductor. Referring to  FIGS. 8A-8B , the exposed surface of an optional nickel shell  839  of a terminal pad  825  generally must be peeled or etched before subsequent plating operations. If nickel shell  839  is peeled, then fragments can stay behind and contaminate subsequent plating operations. Peeling may also tear away too much material, such as portions underneath covercoat  855 , resulting in a gap. If optional nickel shell  839  is etched, then the etching solution will partially dissolve nickel from underneath covercoat  855  at fringe  826 , causing a gap  828 . If the etching solution penetrates all the way through optional nickel shell  839 , then the problem can be exacerbated. An etching solution for nickel is typically stronger than for copper. Thus, once the stronger etching solution penetrates all the way through a nickel protective metal shell, it will attack copper conductor  849  quickly, causing a larger gap. 
     Surface-etching has been observed to cause gaps as large as 1-1.2 μm deep in a conductor, depending on the aggressiveness of the surface etch solution. Furthermore, because a typical polyimide covercoat is formed with a sloping wall, there is less covercoat at the fringe of a terminal pad to seal the underlying conductor from the environment. Both the trapped contamination and thinned covercoat are potential failure points for corrosion. 
     In order to eliminate the overhang and solve the resulting contamination problem, according to the invention a protective metal and a contact metal such as gold are plated to the wire trace before a covercoat is applied. This generally eliminates the need to surface-etch the conductor after the covercoat is applied. Because the surface of the conductor and the surface of the protective metal are not etched or peeled after the covercoat is applied, the bottom surface of the covercoat remains flush with the top surface of the contact metal layer, and no gap is created. 
     In a first aspect, therefore, the invention is an electrical interconnect with a conductor which is substantially coated with nickel and gold shells, including substantially all areas of the conductor underneath the covercoat as well as the terminal pads. The thickness of the gold shell can be generally the same whether the shell is underneath the covercoat or on the terminal pads. Such even-thickness shells can be formed in a single plating bath for each shell. 
     In a second aspect, the invention is an electrical interconnect with a circuit pattern which is made of a conductor, a protective metal coating, and a contact metal coating, substantially underneath a covercoat, where the contact metal coating extends flush underneath the covercoat. The second aspect can include a disk drive head suspension using the electrical interconnect and a hard disk drive which uses the disk drive head suspension. 
     In a third aspect, the invention is an electrical interconnect whose wire trace&#39;s contact metal shell, which overlays a protective metal shell, extends substantially underneath a covercoat in a terminal pad region. The thickness of the contact metal shell underneath the covercoat can be generally the same as the thickness of the contact metal shell on the terminal pad itself. Such a wire trace&#39;s protective metal shell need not be formed by plating, then peeling or etching, then plating; rather, it can be formed in a single plating bath. The third aspect can also include a disk drive head suspension using the electrical interconnect and a hard disk drive which uses the disk drive head suspension. 
     In a fourth aspect, the invention is a method of producing an electrical interconnect by protective-metal-plating and contact-metal-plating an inchoate electrical interconnect before applying a covercoat. The method can also include fill-plating the conductor on the inchoate electrical interconnect after surface-etching to fill in gaps and overhangs and performing a second secondary plating operation after forming a flying lead. 
     Exemplary embodiments of the invention will be further described below with reference to the drawings, in which like numbers refer to like parts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified diagram of a hard disk drive according to an embodiment of the present invention. 
         FIG. 2  is a simplified diagram of an actuator arm assembly with a head suspension according to an embodiment of the present invention. 
         FIG. 3A  is a simplified diagram of a suspension assembly with a head suspension according to an embodiment of the present invention. 
         FIG. 3B  is an exploded view of the suspension assembly in  FIG. 3A . 
         FIG. 4A  is a perspective view of a terminal pad region of an electrical interconnect according to an embodiment of the present invention. 
         FIG. 4B  is a sectional view of the terminal pad region in  FIG. 4A  taken along section line  4 B- 4 B. 
         FIG. 4C  is a sectional view of the terminal pad region in  FIG. 4A  taken along section line  4 C- 4 C. 
         FIG. 5  is an exploded view of a terminal pad. 
         FIG. 6  is a diagram illustrating a set of plating baths which can be used to produce an embodiment of the present invention. 
         FIGS. 7A-7D  are process drawings illustrating conductor etching and plating operations according to the prior art. 
         FIGS. 8A-8B  are process drawings illustrating conductor etching and plating operations according to the prior art. 
         FIGS. 9A-9J  are process drawings showing an embodiment of a production method of an electrical interconnect in accordance with the present invention, where: 
         FIG. 9A  shows the providing of an insulating base on top of a supporting substrate; 
         FIG. 9B  shows the forming of a seed layer; 
         FIG. 9C  shows the applying of a plating resist pattern; 
         FIG. 9D  shows the conductor-plating of a conductor; 
         FIG. 9E  shows the stripping of the plating resist pattern; 
         FIG. 9F  shows the etching of the seed layer; 
         FIG. 9G  shows the surface-etching of the conductor; 
         FIG. 9H  shows protective-metal-plating; 
         FIG. 9I  shows contact-metal-plating; and 
         FIG. 9J  shows the applying of a covercoat. 
         FIGS. 10A-10R  are process drawings showing an embodiment of a production method of an electrical interconnect with a grounding feature and a flying lead in accordance with the present invention, where: 
         FIG. 10A  shows the providing of a supporting substrate; 
         FIG. 10B  shows the applying of an insulating base; 
         FIG. 10C  shows the forming of a seed layer; 
         FIG. 10D  shows the applying of a plating resist; 
         FIG. 10E  shows the conductor-plating of a conductor; 
         FIG. 10F  shows the stripping of the plating resist; 
         FIG. 10G  shows the etching of the seed layer; 
         FIG. 10H  shows the surface-etching of the conductor; 
         FIG. 10I  shows fill-plating the conductor; 
         FIG. 10J  shows protective-metal-plating; 
         FIG. 10K  shows contact-metal-plating; 
         FIG. 10L  shows the applying of a covercoat; 
         FIG. 10M  shows the applying of an etch resist; 
         FIG. 10N  shows the etching of the supporting substrate; 
         FIG. 10O  shows the removing of the insulating base; 
         FIG. 10P  shows the stripping of the etch resist; 
         FIG. 10Q  shows protective-metal-plating a second time; and 
         FIG. 10R  shows contact-metal-plating a second time. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIG. 1 , a typical hard disk drive  100  includes at least one data storage disk  101  (e.g., one, two, three, or more disks), at least one actuator arm  103  (e.g., one, two, three, or more actuator arms), and at least one suspension assembly  105  (e.g., one, two, three, or more suspension assemblies). Each suspension assembly is composed of a head suspension  107  and a slider  109 . This diagram, as well as other diagrams provided herein, is merely an example, which should not unduly limit the scope of the claims herein. One of ordinary skill in the art would recognize many other variations, modifications, and alternatives. 
     Disk  101 , commonly called a platter, rotates about a fixed axis (or spindle) from about 5,000 rpm up to about 15,000 rpm depending upon the drive. Disk  101  stores information and thus often includes a magnetic medium such as a ferromagnetic material. However, it can also include optical materials, commonly coated on surfaces of the disk, which become active regions for storing digital bit information. 
     Suspension assembly  105 , which overlies (or underlies) a surface of disk  101 , operates and controls slider  109  coupled to a read/write head (not shown). Slider  109  is attached to suspension assembly  105  which is in turn is connected to actuator arm  103 . Actuator arm  103  is connected to a voice coil motor or VCM, which moves suspension assembly  105  about a pivot point in an annular manner. 
     With reference to  FIG. 2 , actuator arm assembly  200  can include one, two, three, or more actuator arms. In this embodiment, actuator arm assembly  200  includes two actuator arms  203 . At a distal portion of each actuator arm  203 , a base plate  214  (or mounting plate) connects head suspension  207  to each actuator arm  203  via a hinge member  217 , which can be constructed with a proximal portion providing for actuator coupling (via a base plate or, alternatively, directly to an actuator arm). Hinge member  217  provides the needed spring relationship between head suspension  207  and actuator arm  203 . Each hinge member  217  can be comprised of a springing metal layer, or any other material providing a suitable spring relationship between head suspension  207  and the actuator arm  203 . 
       FIG. 3A  is a simplified view of a suspension assembly  305 , complete with a base plate  314 , head suspension  307 , and slider  309 . Overlaid on the suspension assembly is an electrical interconnect  319  having a connecting terminal portion  322 . Connecting terminal portion  322  includes terminal pad regions  323 . 
       FIG. 3B  is an exploded view of the suspension assembly shown in  FIG. 3A . Head suspension  307  is shown split apart, with load beam  313  and flexure  315  separated. In this embodiment, dimple  311  is shown on load beam  313  of the head suspension. A flexure  315  of head suspension  307  holds slider  309 . Overlaid on load beam  313  and flexure  315  of head suspension  307  is electrical interconnect  319 . 
     An electrical interconnect is sometimes called a flexible (or flex) circuit, a wired circuit board, or an integrated wire harness. Electrical interconnects on disk drive head suspensions are commonly formed by an additive process in which layers of metal are sputtered, plated, etched, and surface-etched, and insulators are laid down, exposed, developed, and washed away in selective areas to create intricate conductive paths overlaid by an insulator. The metals suitable for electrical signals in an electrical interconnect are commonly called a wire trace. The arrangement of one or more metals in an electrical interconnect is sometimes called a wiring pattern or a circuit pattern. 
       FIG. 4A  is a perspective view of two terminal pad regions  323 . Each terminal pad region  323  includes a portion of wire trace  421  having a terminal pad  425 . Terminal pad  425  has a terminal pad top  427  and a terminal pad side  429 . Covercoat  455  defines a covercoated area  431  of wire trace  421 . 
       FIG. 4B  and  FIG. 4C  are sectional views of terminal pad region  323  in  FIG. 4A  taken along section lines  4 B- 4 B and  4 C- 4 C, respectively. Wire trace  421 , including covercoated area  431  adjacent to terminal pad  425 , has a conductor  449 , a protective metal shell  439 , and a contact metal shell  437 . Exposed surface  433  is on the surface of exposed portion  434  of wire trace  421 . If contact metal shell  437  is gold, then terminal pad  425  has an exposed gold top  427  and side  429 . Covered surface  435  is on the surface of covered portion  436  of the wiring trace. Contact metal shell  437  has the same general thickness in its exposed portion  434  as in its covered portion  436 . A top surface  475  of contact metal shell  437  extends from exposed surface  433  flush underneath covercoat  455  to covered surface  435 . 
       FIG. 5  is an exploded, perspective view of a portion of one of the terminal pad regions  323  of  FIG. 4A . Contact metal shell  437  covers a protective metal shell  439 , which in turn covers a conductor  449 . 
     A shell is sometimes called a coating. For example a protective metal shell is the same as a protective metal coating, and a contact metal shell is the same as a contact metal coating. A shell or coating has a top and sides in the same orientation as the top and sides of the insulating base. A shell or coating can but need not coat or cover substantially all of an underlying surface. For example, the upper and side surfaces of conductor  449  can be in intimate contact with protective shell  439 . A side need not extend vertically; a side can include a gently rising slope. A top need not extend horizontally; a top can include sloping areas. Substantially all can include 90%, 95%, or more of the underlying surface. 
     Protective metal shell  439  is preferably an electroless nickel plated shell. Both protective metal shell  439  and contact metal shell  437  may cover only the top and sides of conductor  449 , or may also cover underneath conductor  449 . Covercoat  455  covers contact metal shell  437  in covercoated area  431 . Covercoat  455  has a bottom surface  473 . One way to form the metal shells is in successive plating baths. 
       FIG. 6  is a diagram of three plating baths. Immersion of a workpiece  650  with conductor  649  in all three plating baths can follow a single surface-etching of the conductor. 
     First, workpiece  650  with conductor  649  can be immersed in a fill-plating bath  661 , to fill-plate a fill metal in and around conductor  649 . A fill metal is usually the same metal as the conductor. Fill-plating is generally to fill in gaps and holes in a conductor. 
     Second, whether or not the conductor is fill-plated in fill-plating bath  661 , workpiece  650  with conductor  649  can be immersed in protective-metal-plating bath  663 , to protective-metal-plate a protective metal over conductor  649 . The result is a protective metal shell over conductor  649 . 
     Third, workpiece  650  with conductor  649  and a protective metal shell can be moved from protective-metal-plating bath  663  to contact-metal-plating bath  665  such that the protective metal shell does not dry out. In contact-metal-plating bath  665 , the protective metal shell can be plated over with a contact metal shell. 
     If workpiece  650  with conductor  649  with the protective metal shell is moved from protective-metal-plating bath  663  to contact-metal-plating bath  665  in such a way that the protective metal shell does not dry out, then there is less of a chance that the protective metal will oxidize. If the protective metal does not oxidize, then it is not critical to prepare or activate the surface of the protective metal with a surface etch before the next plating operation begins. The workpiece may be moved between plating baths in a high humidity environment, or in a low humidity environment if the workpiece is moved quickly. Preferably, workpiece  650  is moved from protective-metal-plating bath  663  to contact-metal-plating bath  665  within one minute, or more preferably within 30 seconds. 
     Similar to the movement from protective-metal-plating bath  663  to contact-metal-plating bath  665 , the movement between fill-plating bath  661  and protective-metal-plating bath  663  can be accomplished sufficiently quickly so as to prevent the conductor or its fill metal from drying out. 
     A surface is deemed not to have dried out if a portion of the surface remains wet with the liquid from a plating bath. As one skilled in the art would realize, a workpiece does not need to be fully immersed in a plating bath to be plated. 
       FIGS. 9A-9J  are process drawings showing an embodiment of a production method of an electrical interconnect in accordance with the present invention.  FIGS. 9A-9D  show initial processes in the production method, while  FIGS. 9E-9J  show subsequent processes in the production method. 
       FIG. 9A  shows the providing of an insulating base  943  formed on the top of a supporting substrate  941 . 
     Insulating base  943  can be a polyimide film. No particular limitation is imposed on the insulating material used to form insulating base  943 , provided that the material is an insulator compatible for use in head suspension. Examples of such insulators include epoxies and synthetic resins including polyimide resin, polyamide-imide resin, acrylic resin, polyether nitrile resin, polyethylene naphthalate resin, and polyvinyl chloride resin. Of these resins, a photosensitive synthetic resin is preferable, and a photosensitive polyimide resin is more preferable. Insulating base  943  can be of any thickness compatible for use in a head suspension, including 15 micrometers (μm) thick. 
     No particular limitation is imposed on the material used for supporting substrate  941  provided that the material is compatible for use in a head suspension. Examples of such materials include stainless steel, aluminum, copper-beryllium, and phosphor bronze. Supporting substrate  941  can also be of varying thicknesses, including 30 μm thick. 
       FIG. 9B  shows the forming of a seed layer  945  on top of insulating base  943 . Materials for seed layer  945  often include chromium (Cr), copper (Cu), or both. If both materials are used, then typically chromium is first sputtered on the insulating base, then copper is sputtering over the chromium. The thickness of the chromium is preferably in the range of 100-600 angstroms (Å), and the thickness of the copper is preferably in the range of 500-2000 Å. 
       FIG. 9C  shows the applying of plating resist pattern  947  on seed layer  945 .  FIG. 9D  shows the conductor-plating of conductor  949  on seed layer  945  in a reversal pattern with respect to plating resist pattern  947 . No particular limitation is imposed on the material used for the conductor provided that the material is conducting and compatible for use in a disk drive head suspension. For example, the material of the conductor can be copper, nickel, gold, or alloys of the foregoing, preferably an alloy containing copper. The plating can be performed in many ways, including electrolytic copper plating at room temperature. The thickness of the conductor usually is in the range of 3-35 μm, or preferably 5-18 μm. 
       FIG. 9D  also illustrates what may be called an inchoate wired circuit board, with the pattern of conductor  949  defining a wire trace  921  in reversal pattern with respect to plating resist pattern  947  on top of seed layer  945 , on top of insulating base  943 . 
       FIG. 9E  shows the stripping of plating resist pattern  947  shown in  FIG. 9D  from areas adjacent conductor  949 .  FIG. 9F  shows the etching of seed layer  945  from areas that had previously underlain plating resist pattern  947 .  FIG. 9G  shows the surface-etching of the top and sides of conductor  949  as well as the side of seed layer  945 .  FIG. 9H  shows protective-metal-plating a protective metal  951 , such as nickel, on the top and sides of conductor  949  and on the side of seed layer  945 . The thickness of protective metal  951  is preferably 1-5 μm, but may be 0.5-0.1 μm while still providing corrosion resistance. 
       FIG. 9I  shows contact-metal-plating a contact metal  953 , such as gold, on the top and side of protective metal  951 . The thickness of contact metal  953  is preferably 1-5 μm. 
       FIG. 9J  shows the application of a covercoat  955  over contact metal  953 . The non-covercoated, or exposed portion of at least one terminal pad  925  has an exposed top  927  and an exposed side  929 . No particular limitation is imposed on material used for covercoat  955  provided that the material is compatible for use in a disk drive head suspension. For example, the material can be a synthetic resin such as polyimide, polyether nitrile, polyether sulfone, polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride. The thickness of the covercoat layer is preferably 1-30 μm, and more preferably 2-5 μm. 
       FIGS. 10A-10R  are process drawings showing an embodiment of a production method of an electrical interconnect in accordance with the present invention used to produce an electrical interconnect with a flying lead, shown on the left of the progressing figures, and a grounding feature, shown on the right of the progressing figures. 
       FIG. 10A  shows the providing of a supporting substrate  1041 .  FIG. 10B  shows the application of an insulating base  1043  onto portions of supporting substrate  1041 .  FIG. 10C  shows the deposition of a seed layer  1045  on both insulating base  1043  and exposed areas of supporting substrate  1041 .  FIG. 10D  shows the application of a plating resist pattern  1047  over portions of seed layer  1045 . 
       FIG. 10E  shows the conductor-plating of a conductor  1049  on top of exposed portions of seed layer  1045 , opposite supporting substrate  1041 .  FIG. 10F  shows the stripping of plating resist pattern  1047  shown in  FIG. 10E .  FIG. 10G  shows the etching of exposed portions of seed layer  1045  from insulating base  1043  and supporting substrate  1041 .  FIG. 10H  shows the surface-etching of conductor  1049  and sides of seed layer  1045  in preparation for plating. 
       FIG. 10I  shows the fill-plating of a fill metal  1057  on conductor  1049 .  FIG. 10J  shows protective-metal-plating a protective metal  1051  over conductor  1049  and fill metal  1057 .  FIG. 10K  shows contact-metal-plating a contact metal  1053  over protective metal  1051 .  FIG. 10L  shows the application of a covercoat  1055  over portions of contact metal  1053 . 
     The rectangular feature on the left of the figure is an inchoate flying lead  1067  which is left exposed. The rest of the figures will show the further processing of inchoate flying lead  1067 . The “V”-shaped feature on the right of the figure is a grounding feature  1069 . Grounding feature  1069  is grounded to supporting conductive substrate  1041 . 
       FIG. 10M  shows the application of etch resist patterns  1059  to both the top and bottom of the workpiece, with the bottom having an exposed portion of supporting substrate  1041  underneath inchoate flying lead  1067 .  FIG. 10N  shows the bottom-etching of a portion of supporting substrate  1041  from underneath inchoate flying lead  1067 .  FIG. 10O  shows the bottom-etching of a portion of insulating base  1043  from underneath flying lead  1067 . Flying lead  1067  now has an exposed bottom surface  1071 .  FIG. 10P  shows the stripping of etch resist pattern  1059  shown in  FIG. 10O  so that flying lead  1067  is entirely exposed. 
       FIG. 10Q  shows a second protective-metal-plating, performed to protective-metal-plate the bottom of a flying lead  1067  with protective metal  1051 .  FIG. 10R  shows a second contact-metal-plating, performed to contact-metal-plate the bottom of flying lead  1067  with contact metal  1053 . The result is an electrical interconnect with a flying lead and a grounding feature. 
     It will be appreciated that the term “present invention” as used herein should not be construed to mean that only a single invention having a single essential element or group of elements is presented. Similarly, it will also be appreciated that the term “present invention” encompasses a number of separate innovations which can each be considered separate inventions. Although the present invention has thus been described in detail with regard to the preferred embodiments and drawings thereof, it should be apparent to those skilled in the art that various adaptations and modifications of the present invention may be accomplished without departing from the spirit and the scope of the invention. Accordingly, it is to be understood that the detailed description and the accompanying drawings as set forth hereinabove are not intended to limit the breadth of the present invention, which should be inferred only from the following claims and their appropriately construed legal equivalents.