JP6191931B2 - Suspension substrate, suspension, suspension with head, hard disk drive, and method for manufacturing suspension substrate - Google Patents

Description

  The present invention relates to a method for manufacturing a suspension substrate, a suspension, a suspension with a head, a hard disk drive, and a suspension substrate. The present invention relates to a suspension substrate, a suspension, a suspension with a head, a hard disk drive, and a method for manufacturing a suspension substrate that can improve the reliability of electrical connection with an actuator element.

  In general, a hard disk drive (HDD) includes a suspension board on which a magnetic head slider for writing and reading data to and from a disk storing data is mounted. The suspension substrate includes a metal support layer and a wiring layer having a plurality of wirings stacked on the metal support layer with an insulating layer interposed therebetween. To write or read data.

  In such a hard disk drive, in order to move the magnetic head slider to a desired data track on the disk, a VCM actuator (for example, a voice coil motor) that rotates an actuator arm that supports the magnetic head slider is used as a servo control system. Is controlled by.

  By the way, in recent years, the track width has been reduced by increasing the density of the disk. For this reason, it may be difficult to accurately align the magnetic head slider to a desired track by the VCM actuator.

  In order to cope with this, a dual actuator type suspension is known in which a VCM actuator and a PZT microactuator (Dual Stage Actuator: DSA) cooperate to move a magnetic head slider to a desired track (for example, , See Patent Document 1). This PZT microactuator is constituted by a piezoelectric element such as a piezoelectric element made of PZT (lead zirconate titanate), and expands and contracts when a voltage is applied to move the magnetic head slider minutely. In such a dual actuator type suspension, the VCM actuator roughly adjusts the position of the magnetic head slider, and the PZT microactuator finely adjusts the position of the magnetic head slider. In this way, the magnetic head slider is aligned with a desired track quickly and accurately.

  In the suspension substrate shown in Patent Document 1, a through hole is provided in the electrical insulating layer in the terminal portion for supplying power to the piezoelectric element so that the copper terminal is exposed, and a stainless steel ring is provided on the surface of the electrical insulating layer on the piezoelectric element side. Is provided. By injecting a liquid conductive adhesive inside the stainless steel ring, the conductive adhesive is bonded to the copper terminal and the piezoelectric element, and the piezoelectric element is electrically connected to the copper terminal. Yes.

JP2011-238860A

  However, the bonding area between the conductive adhesive and the stainless steel ring is limited due to space constraints. Accordingly, there is a problem that it is difficult to improve the bonding strength between the conductive adhesive and the stainless steel ring and to improve the reliability of the electrical connection between the piezoelectric element and the suspension substrate.

By the way, silver paste is mainly used for the conductive adhesive for joining the copper terminal of the suspension substrate and the piezoelectric element for the following reasons. That is, silver or gold is generally used as the electrode of the piezoelectric element, but such a metal is soluble in tin contained in solder. For this reason, when the soldering operation time becomes long, the silver or gold of the electrode melts into the solder, and the electrode of the piezoelectric element disappears.
In order to prevent the disappearance of the electrode, there is a measure to contain several percent of gold or silver in the solder. However, even if such a measure is taken, it is difficult to completely prevent the disappearance of the electrode. It is. Moreover, depolarization may be caused by the temperature rise during the soldering operation. From such a viewpoint, a silver paste that is not soluble in tin and has a low adhesion temperature is used.

  Silver paste is required not only to have bonding properties but also to have a low glass transition temperature to prevent depolarization and to displace the slider effectively against expansion and contraction of piezoelectric elements. A low elastic modulus is required. By the way, in order to improve the electrical conductivity of the silver paste, it is considered effective to increase the content of the silver filler. However, when the content of the silver filler is increased, the glass transition temperature of the silver paste is increased. There's a problem. Further, it is considered effective to refine the silver filler in order to improve the bondability of the silver paste. However, when the silver filler is refined, there is a problem that the elastic modulus of the silver paste increases. From these facts, it is difficult to improve the conductivity and bonding property between the silver paste and the terminals of the suspension substrate by improving the silver paste as the conductive adhesive.

  The present invention has been made in consideration of the above points, and improves the reliability of bonding between the conductive adhesive and the connection structure region of the suspension substrate, and the reliability of the electrical connection with the actuator element. It is an object of the present invention to provide a suspension substrate, a suspension, a suspension with a head, a hard disk drive, and a method for manufacturing a suspension substrate that can improve performance.

  As a first solution, the present invention provides a suspension substrate having a connection structure region that can be connected to an actuator element via a conductive adhesive containing conductive particles, an insulating layer, and the actuator element of the insulating layer. A metal support layer provided on the surface of the insulating layer, and a wiring layer provided on the surface of the insulating layer opposite to the actuator element, wherein the wiring layer is provided in the connection structure region with a plurality of wires. The wiring layer having a wiring connection portion connected to the wiring and electrically connected to the actuator element through the conductive adhesive, and the actuator element of the metal support layer. A gold plating layer to be bonded to the conductive adhesive is provided on the side surface, and the gold plating layer is provided on the outer periphery of the outer periphery. To provide a substrate for suspension, characterized in that a.

  In the suspension substrate according to the first solving means described above, the connection structure region has a metal support layer through-hole penetrating the metal support layer and an insulating layer through-hole penetrating the insulating layer, The surface of the wiring layer on the actuator element side may be exposed, and an injection hole through which the conductive adhesive is injected may be provided at least partially.

  Further, in the suspension substrate according to the first solving means described above, the gold plating layer is formed in a ring shape so as to surround the injection hole in a plan view, and the gold plating layer is provided on an inner peripheral surface thereof. Moreover, you may make it have the inner periphery uneven | corrugated | grooved part formed in uneven | corrugated shape by planar view.

  In the suspension substrate according to the first solution described above, the wiring connection portion and the metal support layer may be connected by a conductive connection portion that penetrates the insulating layer.

  In the suspension substrate according to the first solving means described above, a surface of the wiring connection portion on the actuator element side may be covered with the insulating layer and the metal support layer.

  In the suspension substrate according to the first solution described above, the gold plating layer may be formed in a circular shape in plan view.

  Further, in the suspension substrate according to the first solving means described above, the gold plating layer is formed in a ring shape in a plan view, and the gold plating layer is provided in an uneven shape in a plan view provided on the inner peripheral surface thereof. You may make it have the inner periphery uneven | corrugated | grooved part formed in this.

  In the suspension substrate according to the first solving means described above, the connection structure region includes a metal support layer through-hole penetrating the metal support layer and an insulating layer through-hole penetrating the insulating layer. The surface of the wiring layer on the actuator element side may be exposed, and an injection hole through which the conductive adhesive is injected may be provided at least partially.

  In the suspension substrate according to the first solving means described above, the metal support layer has a through hole defining surface that defines the metal support layer through hole, and the gold plating layer is formed on the through hole defining surface. It may be extended.

  Further, in the suspension substrate according to the first solving means described above, the gold plating layer is formed in a ring shape so as to surround the injection hole in a plan view, and the gold plating layer is provided on an inner peripheral edge thereof. Moreover, you may make it have the inner periphery uneven | corrugated | grooved part formed in uneven | corrugated shape by planar view.

  In the suspension substrate according to the first solving means described above, the uneven height of the outer peripheral uneven portion may be 0.0015 mm to 0.0200 mm.

  Further, the present invention provides a suspension substrate having a connection structure region connectable to an actuator element via a conductive adhesive containing conductive particles, as a second solving means, comprising: an insulating layer; A metal support layer provided on a surface on the actuator element side; and a wiring layer provided on a surface of the insulating layer opposite to the actuator element, wherein the wiring layer is provided in the connection structure region. A wiring connection portion connected to the corresponding wiring and electrically connected to the actuator element via the conductive adhesive, and in the connection structure region, A metal support layer through-hole penetrating the metal support layer and an insulating layer through-hole penetrating the insulating layer, exposing the surface of the wiring layer on the actuator element side, An injection hole for injecting the conductive adhesive is provided at least in part, and a gold plating layer bonded to the conductive adhesive is provided on the surface of the wiring connection portion exposed by the injection hole. The gold plating layer is provided with a suspension substrate, characterized in that it has an outer peripheral uneven portion formed on the outer peripheral surface of the gold plating layer so as to be uneven in a plan view.

  In the suspension substrate according to the second solution described above, a nickel plating layer is interposed between the wiring connection portion and the gold plating layer, and the nickel plating layer is exposed by the injection hole. You may make it cover the whole surface of a wiring connection part.

  In the suspension substrate according to the second solving means described above, the uneven height of the outer peripheral uneven portion may be 0.0015 mm to 0.0200 mm.

  The present invention is a base plate, the above-described suspension substrate attached to the base plate via a load beam, and joined to at least one of the base plate and the load beam, and the connection structure region of the suspension substrate. And the actuator element connected via the conductive adhesive.

  The present invention provides a suspension with a head comprising the above-described suspension and a head slider mounted on the suspension.

  The present invention provides a hard disk drive including the above-described suspension with a head.

  As a third solution, the present invention provides a method for manufacturing a suspension substrate having a connection structure region that can be connected to an actuator element via a conductive adhesive containing conductive particles. A step of preparing a laminate having a metal support layer provided on one surface and a wiring layer provided on the other surface of the insulating layer; a plurality of wires in the wiring layer; and the connection structure A wiring connection portion provided in a region and connected to the corresponding wiring and electrically connected to the actuator element via the conductive adhesive; and the metal support layer Forming a gold plating layer to be bonded to the conductive adhesive on the surface of the actuator element, and in the step of forming the gold plating layer, the actuator of the metal support layer Gold plating is performed on the surface on the side of the data element using a resist having a resist concavo-convex portion in which the periphery of the resist opening is formed in a concavo-convex shape in plan view. Provided is a method for manufacturing a suspension substrate, wherein an outer peripheral uneven portion formed in an uneven shape in a plan view is formed on the periphery.

  As a fourth solution, the present invention provides a method for manufacturing a suspension substrate having a connection structure region that can be connected to an actuator element via a conductive adhesive containing conductive particles. A step of preparing a laminate having a metal support layer provided on one surface and a wiring layer provided on the other surface of the insulating layer; a plurality of wires in the wiring layer; and the connection structure A step of forming a wiring connection portion provided in a region and connected to the corresponding wiring and electrically connected to the actuator element via the conductive adhesive, and in the metal support layer, A step of forming a metal support layer through hole provided in the connection structure region and penetrating the metal support layer; and an insulating layer through hole penetrating the insulating layer in the insulating layer, the metal support layer A step of exposing the surface on the actuator element side of the wiring connection portion together with the layer through hole, and forming the insulating layer through hole constituting the injection hole into which the conductive adhesive is injected at least partially; Forming a gold plating layer bonded to the conductive adhesive on the surface of the wiring connection portion exposed by the injection hole, and in the step of forming the gold plating layer, the wiring connection portion Gold plating is applied to the surface of the actuator element side using a resist having a resist concavo-convex portion in which the periphery of the resist opening is formed in a concavo-convex shape in plan view, and the gold plating layer thus formed A method of manufacturing a suspension substrate is provided in which an outer peripheral uneven portion formed in an uneven shape in plan view is formed on the outer peripheral edge of the suspension.

  According to the present invention, the bonding reliability between the conductive adhesive and the connection structure region of the suspension substrate can be improved, and the reliability of the electrical connection with the actuator element can be improved.

FIG. 1 is a plan view showing an example of a suspension substrate according to an embodiment of the present invention. FIG. 2 is a view showing a cross section of a connection structure region in the suspension substrate of FIG. FIG. 3 is a plan view of the bonding gold plating layer as viewed from the direction A in FIG. 2. FIG. 4 is a photograph showing an enlarged outer peripheral edge of the plating layer in part B of FIG. FIG. 5 is an enlarged plan view showing an outer peripheral edge of the bonding gold plating layer. FIG. 6 is a cross-sectional photograph showing a silver paste. FIG. 7 is a graph showing the length of the silver filler contained in the silver paste after low-temperature sintering. FIG. 8 is a plan view showing an example of the suspension in the embodiment of the present invention. FIG. 9 is a back view showing a part of the suspension of FIG. FIG. 10 is a perspective view showing an example of a piezo element in the suspension of FIG. FIG. 11 is a view showing a cross section of the connection structure region in the suspension of FIG. FIG. 12 is a plan view showing an example of a suspension with a head according to the embodiment of the present invention. FIG. 13 is a perspective view showing an example of a hard disk drive in the embodiment of the present invention. 14 (a) to 14 (g) are diagrams showing a method for manufacturing a suspension substrate in the embodiment of the present invention. FIGS. 15A to 15C are views showing a method of forming a resist used in the plating process of FIGS. 14E and 14F. FIG. 16 is an enlarged plan view showing the periphery of the resist opening of the resist. FIG. 17 is a cross-sectional view showing a modified example (modified example 1) of the connection structure region. FIG. 18 is a cross-sectional view showing a modified example (modified example 2) of the connection structure region. FIG. 19 is a plan view of the bonding gold plating layer as seen from the direction C in FIG. FIG. 20 is a cross-sectional view showing a modified example (modified example 3) of the connection structure region. FIG. 21 is a cross-sectional view showing a modified example (modified example 4) of the connection structure region. FIG. 22 is a plan view of the bonding gold plating layer viewed from the direction D of FIG. FIG. 23 is a plan view showing a modification (modification 5) of the bonding gold plating layer. FIG. 24 is a cross-sectional view showing a modified example (modified example 6) of the connection structure region. FIG. 25 is a cross-sectional view showing a modified example (modified example 7) of the connection structure region. FIG. 26 is a partially enlarged plan view of an exposure mask showing a modification (Modification 8) of the method for manufacturing the suspension substrate.

  A method for manufacturing a suspension substrate, a suspension, a suspension with a head, a hard disk drive, and a suspension substrate according to an embodiment of the present invention will be described with reference to FIGS. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual ones.

  As shown in FIG. 1, the suspension substrate 1 has a substrate body region 2 and a pair of piezo elements (actuator element, see FIG. 8) 44 with a conductive adhesive (for example, silver paste) containing conductive particles. And a connection structure region 3 that can be connected. Of these, the board body area 2 has a head area 2a on which a head slider 52 (see FIG. 12) described later is mounted, and a tail area 2b to which an FPC board (external device, see FIG. 12) 71 is connected. ing. A plurality of head terminals 5 connected to the head slider 52 are provided in the head region 2a, and a plurality of tail terminals (external device connection terminals) 6 connected to the FPC board 71 are provided in the tail region 2b. The head terminal 5 and the tail terminal 6 are connected to each other via a signal wiring 13a described later. Further, the pair of connection structure regions 3 are arranged on both sides of the substrate body region 2 and are connected to the substrate body region 2 via the connection region 4.

  As shown in FIGS. 1 and 2, the suspension substrate 1 includes an insulating layer 10, a metal support layer 11 provided on one surface of the insulating layer 10 (surface on the side of the piezo element 44 to be connected), The wiring layer 12 is provided on the other surface of the insulating layer 10 (surface opposite to the piezo element 44) and includes a plurality of wirings 13a, 13b, and 13c. Although not shown, a seed layer made of nickel (Ni), chromium (Cr), and copper (Cu) and having a thickness of about 300 nm is interposed between the insulating layer 10 and the wiring layer 12, so The adhesion between the layer 10 and the wiring layer 12 is improved.

  As shown in FIG. 1, the plurality of wirings include a signal wiring 13 a including a pair of reading wirings and a pair of writing wirings, and a pair of element wirings 13 b connected to the piezo element 44. Among these, the pair of element wirings 13 b are electrically connected to each other via the metal support wiring portion 11 b of the metal support layer 11. The metal support wiring portion 11b of the metal support layer 11 is separated from the main body portion 11a of the metal support layer 11 and formed in an island shape, and is electrically insulated from the main body portion 11a. . The metal support wiring portion 11 b of the metal support layer 11 and the element wiring 13 b are electrically connected to each other by a wiring via 27 that penetrates the insulating layer 10. In this way, the two element wires 13b extending from the piezo element 44 merge in the substrate body region 2 and are connected to the corresponding one tail terminal 6 provided in the tail region 2b. Thereby, the voltage applied to the pair of piezo elements 44 is made uniform, and the accuracy of the expansion / contraction amount of each piezo element 44 is improved.

  The head region 2a is provided with a ground via 28 for grounding the head terminal 5 for grounding. The ground via 28 is connected to the head terminal 5 for grounding via the ground wiring 13 c and passes through the insulating layer 10 to electrically connect the head terminal 5 for grounding and the main body portion 11 a of the metal support layer 11. Connected.

  As shown in FIGS. 1 and 2, the wiring layer 12 has a wiring connection portion 16 provided in each connection structure region 3. Each wiring connection portion 16 is connected to the corresponding element wiring 13b and is electrically connected to the piezo element 44 via a conductive adhesive.

  The metal support layer 11 has a ring-shaped metal frame portion 17 provided in the connection structure region 3. As shown in FIG. 1, the metal frame body portion 17 is formed in an island shape, and is separated from the main body portion 11 a of the metal support layer 11 in the substrate main body region 2 and is electrically insulated. The insulating layer 10 has a ring-shaped insulating frame 18 provided in the connection structure region 3.

  The metal frame body portion 17 of the metal support layer 11 forms a metal support layer through hole 31 a that penetrates the metal frame body portion 17. Further, the insulating frame body portion 18 of the insulating layer 10 forms an insulating layer through-hole 31b penetrating the insulating frame body portion 18 corresponding to the metal support layer through-hole 31a. In this way, the surface on the piezoelectric element 44 side of the wiring connection portion 16 of the wiring layer 12 is exposed by the metal support layer through hole 31a and the insulating layer through hole 31b. That is, the metal support layer through-hole 31a and the insulating layer through-hole 31b constitute the injection hole 31 that exposes the surface of the wiring connection portion 16 on the piezoelectric element 44 side. In the present embodiment, the wiring connection portion 16 is provided on the insulating layer through hole 31b, and a conductive adhesive is applied to the metal support layer through hole 31a and the insulating layer through hole 31b of the injection hole 31. Injected.

  Nickel (Ni) plating and gold (Au) plating are sequentially applied to the exposed surface of the insulating layer through-hole 31b of the wiring connection portion 16 to form a connection plating layer 32. The connection plating layer 32 includes a connection nickel plating layer 33 provided on the wiring connection portion 16 and a connection gold plating layer 34 provided on the connection nickel plating layer 33. Among these, the thickness of the connecting nickel plating layer 33 is preferably 0.3 μm to 4.0 μm, and the thickness of the connecting gold plating layer 34 is preferably 0.5 μm to 3.0 μm.

  As shown in FIGS. 2 and 3, nickel plating and gold plating are sequentially applied to the surface of the metal frame 17 on the side of the piezo element 44 (the lower surface in FIG. 2) to provide a bonding plating layer 82. ing. The bonding plating layer 82 includes a bonding nickel plating layer 83 provided on the metal frame portion 17 and a bonding gold plating layer 84 provided on the bonding nickel plating layer 83. . Among these, the bonding gold plating layer 84 is bonded to a conductive adhesive bonded to the piezo element 44 as described later (see FIG. 11). The thickness of the bonding nickel plating layer 83 and the thickness of the bonding gold plating layer 84 are preferably the same as the thicknesses of the connection nickel plating layer 33 and the connection gold plating layer 34, respectively.

  The metal frame portion 17 of the metal support layer 11 has a through hole defining surface 17a that defines the metal support layer through hole 31a. The bonding plating layer 82 including the bonding gold plating layer 84 described above may extend to the through hole defining surface 17 a and reach the insulating frame 18 of the insulating layer 10. In addition, the outer diameter of the bonding plating layer 82 is smaller than the outer diameter of the metal frame body portion 17 so that the outer peripheral side region of the metal frame body portion 17 is exposed.

  As shown in FIG. 4 and FIG. 5, the bonding gold plating layer 84 has (preferably a plurality of) outer peripheral uneven portions 85 formed on the outer peripheral edge 84a in an uneven shape in plan view. doing. Each outer peripheral rugged portion 85 includes an outer peripheral concave portion 85a that is recessed inward in a plan view and an outer peripheral convex portion 85b that protrudes outward in a plan view, and is flat so that a silver filler 49b described later can enter. It is formed in an uneven shape visually. Further, in the present embodiment, the outer peripheral edge of the bonding nickel plating layer 83 is also formed in an uneven shape in plan view in the same shape as the bonding gold plating layer 84. Thus, the silver filler 49 can enter and come into contact with the irregularities on the outer peripheral edge of the bonding nickel plating layer 83. Here, the plan view means a state viewed from the stacking direction in which the metal support layer 11, the insulating layer 10, and the wiring layer 12 are stacked, more specifically, the state shown in FIG.

Incidentally, as shown in FIGS. 6 and 7, it is preferable to use a silver paste 49 for the conductive adhesive. The silver paste 49 is, for example, a mixture of a binder base material 49a such as an epoxy resin, a silver colloid, and a silver filler (conductive particles) 49b. After coating, for example, at a temperature of about 150 ° C. to 350 ° C. By heating and sintering at low temperature, the silver colloid becomes silver particles and becomes the silver filler 49b. For this reason, most of the silver filler 49b present in the sintered silver paste 49 is small. The situation is shown in FIG. 6, and the size of the silver filler 49b obtained from the cross-sectional photograph shown in FIG. 6 is shown in FIG. In FIG. 6, as the silver paste 49, a conductive epoxy resin commercially available under the trade name “ABLEBOND 2030SC” manufactured by Able Stick Co./National Starch and Chemical Company is used, and nitrogen (N ₂ ) is used. FIG. 6 shows a cross section of the silver paste 49 when stored in a furnace in an atmosphere and sintered at a low temperature by heating at 150 ° C. for 60 minutes, and the portion that appears black in FIG. 6 corresponds to the binder base material 49a The portion that appears white corresponds to the silver filler 49b. Moreover, the length of the silver filler 49b in FIG. 7 has shown the largest external dimension of the silver filler 49b.

  As shown in FIG. 7, many silver fillers 49b have a length of 0.015 mm or less. For this reason, the uneven height H1 (uneven distance, see FIG. 5) of the outer peripheral uneven portion 85 is preferably 0.0015 mm to 0.0200 mm, and more preferably 0.0015 mm to 0.0100 mm. Thus, by setting the unevenness height to be 0.0015 mm or more, the silver filler 49b can enter and contact the outer peripheral unevenness portion 85 of the bonding gold plating layer 84. Further, by setting the uneven height to 0.0200 mm or less, particularly 0.0100 mm or less, the number of the outer peripheral uneven portions 85 is increased and the probability of bringing the silver filler 49b into contact with the outer peripheral uneven portions 85 is increased. Can do. As a result, the bonding reliability between the bonding gold plating layer 84 and the conductive adhesive can be improved.

  In addition, as shown in FIG. 5, the uneven | corrugated height can consider part of the outer periphery 84a of the gold plating layer 84 for joining using the microscope etc., for example, the arc-shaped outer periphery 84a can be considered as a straight line. It can be measured in a state of being enlarged to a certain extent. For example, when the radius of the outer peripheral edge 84a of the bonding gold plating layer 84 is 0.120 mm, by enlarging to a plane field of 0.100 mm × 0.100 mm using a measuring microscope STM6-LM manufactured by Olympus Corporation, The arc-shaped outer peripheral edge 84a can be regarded as a straight line. In the state shown in FIG. 5, the direction of the linear reference line that can be approximated from the outer peripheral edge 84a that is formed in an uneven shape is defined, and the outer peripheral edge of the outer peripheral uneven portion 85 that is substantially parallel to the direction of the reference line The distance between the valley bottom line of the recess 85a and the peak line of the outer peripheral protrusion 85b can be measured, and the measured distance can be set to the above-described uneven height.

By the way, as shown in FIG. 2, a protective layer 20 is provided on the insulating layer 10 to cover the wiring connection portion 16 of the wiring layer 12. The protective layer 20 is provided with an inspection through hole 21 that exposes a part of the surface of the wiring connection portion 16 on the protective layer 20 side. An inspection plating layer 22 having an inspection nickel plating layer 23 and an inspection gold plating layer 24 is formed on the exposed surface of the wiring connection portion 16 in the inspection through hole 21. The nickel plating layer 23 for inspection and the gold plating layer 24 for inspection can be formed in the same manner as the nickel plating layer 33 and the gold plating layer 34 described above. Since the wiring connection portion 16 is exposed in the inspection through hole 21, a continuity test between the wiring connection portion 16 and the piezoelectric element 44 is performed from the upper surface of the wiring connection portion 16 by using a continuity tester such as a probe. Can be done.
The protective layer 20 is formed so as to cover the wirings 13 a, 13 b, and 13 c of the wiring layer 12 in the substrate main body region 2 and the connection region 4. In FIG. 1, the protective layer 20 is omitted for the sake of clarity.

  As shown in FIG. 1, in the substrate main body region 2, two jig holes 25 are provided through the metal support layer 11 and the insulating layer 10 for alignment with a load beam 43 described later. ing. Each jig hole 25 is disposed on a longitudinal axis (X) of a load beam 43 described later. That is, the longitudinal axis (X) passes through each jig hole 25.

  Next, each component will be described in detail.

  The material of the insulating layer 10 is not particularly limited as long as it is a material having a desired insulating property. For example, it is preferable to use polyimide (PI). Note that the material of the insulating layer 10 can be a photosensitive material or a non-photosensitive material. The thickness of the insulating layer 10 is preferably 5 μm to 30 μm, particularly 8 μm to 10 μm. As a result, it is possible to ensure insulation performance between the metal support layer 11 and the wirings 13a, 13b, and 13c, and to prevent loss of rigidity of the suspension substrate 1 as a whole.

  Each of the wirings 13a, 13b, and 13c is configured as a conductor for transmitting an electrical signal, and the material of each of the wirings 13a, 13b, and 13c is particularly limited as long as it has a desired conductivity. However, it is preferable to use copper (Cu). In addition to copper, any material having electrical characteristics similar to pure copper can be used. Here, it is preferable that the thickness of each wiring 13a, 13b, 13c is, for example, 1 μm to 18 μm, especially 9 μm to 12 μm. As a result, the transmission characteristics of the wirings 13a, 13b, and 13c can be ensured, and the loss of flexibility of the suspension substrate 1 as a whole can be prevented. The head terminal 5, tail terminal 6 and wiring connection portion 16 are formed of the same material and the same thickness as the wirings 13a, 13b and 13c, and constitute the wiring layer 12 together with the wirings 13a, 13b and 13c. doing.

  The metal support layer 11 is made of stainless steel. As a result, the metal support layer 11 has desired conductivity, elasticity, and strength. The thickness of the metal support layer 11 is preferably larger than the thickness of the wirings 13a, 13b, and 13c. Moreover, the thickness of the metal support layer 11 can be 10 micrometers-30 micrometers as an example, and can be 15 micrometers-20 micrometers especially. As a result, the conductivity, rigidity, and elasticity of the metal support layer 11 can be ensured.

  As a material of the protective layer 20, it is preferable to use a resin material such as polyimide. The material of the protective layer 20 can be a photosensitive material or a non-photosensitive material. The thickness of the protective layer 20 is preferably 2 μm to 30 μm.

  Next, the suspension 41 in the present embodiment will be described with reference to FIGS. The suspension 41 shown in FIG. 8 is attached to the base plate 42, the load beam 43 that holds the metal support layer 11 of the suspension substrate 1, the suspension substrate 1, the base plate 42, and the load beam 43. And a piezo element 44 connected to the connection structure region 3 of the suspension substrate 1.

  Of these, the base plate 42 is made of stainless steel, and as shown in FIG. 9, a head side plate 42a disposed on the head region 2a side of the suspension substrate 1 and a tail side plate 42b disposed on the tail region 2b side. And a flexible portion 42c connecting the head side plate 42a and the tail side plate 42b. The base plate 42 has an accommodation opening 42 d for accommodating the piezo element 44. The accommodation opening 42d is formed by a head side plate 42a, a tail side plate 42b, and a flexible portion 42c.

  The load beam 43 is made of stainless steel like the base plate 42, and as shown in FIGS. 8 and 9, the head side beam 43a disposed on the head region 2a side of the suspension substrate 1 and the tail region 2b side. The tail-side beam 43b is disposed, and a flexible portion 43c that connects the head-side beam 43a and the tail-side beam 43b. In addition, the load beam 43 has an exposed opening 43 d that exposes the surface of the piezo element 44 on the connection structure region 3 side. The exposed opening 43d is formed by a head side beam 43a, a tail side beam 43b, and a flexible portion 43c.

  A piezo element 44 is joined to the base plate 42 and the load beam 43 thus formed. That is, as shown in FIGS. 8 and 9, the piezo element 44 is accommodated in the accommodation opening 42 d of the base plate 42, joined to the base plate 42, and joined to the surface of the load beam 43 on the side of the base plate 42. ing. Further, as shown in FIG. 11, the connection structure region 3 of the suspension substrate 1 is connected to the piezo element 44 through the exposed opening 43 d of the load beam 43.

  The load beam 43 is provided with a beam jig hole (not shown) corresponding to each jig hole 25 of the suspension substrate 1. When the load beam 43 is attached to the suspension substrate 1, the suspension beam 1 is suspended. The substrate 1 and the load beam 43 can be aligned. The jig hole of the load beam 43 is disposed on the longitudinal axis (X). The load beam 43 and the suspension substrate 1 are fixed by welding.

  The piezoelectric element 44 is configured as a piezoelectric element that expands and contracts in the direction of the arrow P in FIGS. 8 and 12 when a voltage is applied, and moves the head slider 52 in the sway direction (the turning direction, the arrow in FIGS. 8 and 12). Q direction). As shown in FIG. 10, each piezo element 44 is interposed between a pair of electrodes 44a facing each other and a pair of electrodes 44a, and is formed of a piezoelectric material such as PZT (lead zirconate titanate). Part 44b. The piezoelectric material portions 44b of the pair of piezo elements 44 are formed to have polarization directions different from each other by 180 °. When a predetermined voltage is applied, one piezo element 44 contracts and the other piezo element 44 44 extends. As shown in FIG. 8, such a piezo element 44 is arranged along the longitudinal axis (X) of the load beam 43, and its expansion / contraction direction is parallel to the longitudinal axis (X). Yes. The piezo elements 44 are arranged symmetrically with respect to the longitudinal axis (X) so that the expansion and contraction of each piezo element 44 is evenly transmitted to the head slider 52. Further, in the present embodiment, the connection structure region 3 connected to the piezo element 44 is disposed on both sides of the substrate body region 2, and the expansion and contraction of the piezo element 44 is effectively converted into the displacement of the head slider 52. It can be used now.

  As shown in FIG. 11, each piezo element 44 is joined to the base plate 42 and the load beam 43 via a nonconductive adhesive portion 46 made of a nonconductive adhesive. Further, as shown in FIGS. 9 and 11, the electrode 44a on one side of the piezo element 44 (the side opposite to the suspension substrate 1) is connected to the base plate 42 via a first conductive adhesive portion 47 made of a conductive adhesive. Is electrically connected. Furthermore, the other electrode 44a (the suspension substrate 1 side) of the piezo element 44 is joined to the wiring connection portion 16 via a second conductive adhesive portion 48 made of a conductive adhesive, as shown in FIG. And electrically connected. That is, a second conductive adhesive portion 48 made of a conductive adhesive is formed between the wiring connection portion 16 and the piezo element 44, and the piezo element 44 is connected to the wiring connection portion 16 via the second conductive adhesive portion 48. While being joined, the other electrode 44 a of the piezo element 44 is electrically connected to the wiring connection portion 16 via the second conductive adhesive portion 48. Here, FIG. 11 shows a cross section along the longitudinal axis (X) of the connection structure region 3 as an example. FIG. 11 shows an example in which the connection structure region 3 of the suspension substrate 1 is slightly pushed toward the piezo element 44 due to the flexibility of the connection region 4.

  Next, referring to FIG. 12, the suspension with head 51 in the present embodiment will be described. A suspension 51 with a head shown in FIG. 12 has the above-described suspension 41 and a head slider 52 mounted on the suspension substrate 1 and connected to the head terminal 5.

  Next, the hard disk drive 61 in the present embodiment will be described with reference to FIG. A hard disk drive 61 shown in FIG. 13 is provided with a case 62, a disk 63 that is rotatably attached to the case 62, stores data, a spindle motor 64 that rotates the disk 63, and a desired flying height on the disk 63. And a suspension 51 with a head including a head slider 52 that writes and reads data to and from the disk 63. Among them, the suspension with head 51 is attached to the case 62 so as to be movable, and the voice coil motor 65 for moving the head slider 52 of the suspension with head 51 along the disk 63 is attached to the case 62. Yes. The suspension 51 with the head is attached to the voice coil motor 65 via the arm 66, and is connected to an FPC board 71 (see FIG. 12) connected to a control unit (not shown) that controls the hard disk drive 61. ing. In this way, an electrical signal is transmitted between the control unit and the head slider 52 via the suspension board 1 and the FPC board 71.

  Next, a method for manufacturing the suspension substrate 1 according to the present embodiment will be described. Here, as an example, a method of manufacturing the suspension substrate 1 by the subtractive method will be described with reference to FIGS. 14 and 15 showing a cross section of the connection structure region 3.

  First, the insulating layer 10, the metal support layer 11 provided on one surface of the insulating layer 10 (the surface on the side of the piezo element 44 to be connected), the wiring layer 12 provided on the other surface of the insulating layer 10, and Are prepared (see FIG. 14A). In this case, first, the metal support layer 11 is prepared, and the insulating layer 10 is formed on the metal support layer 11 by a coating method using non-photosensitive polyimide. Subsequently, nickel, chromium and copper are sequentially coated on the insulating layer 10 by a sputtering method to form a seed layer (not shown). Thereafter, the wiring layer 12 is formed by copper plating using the seed layer as a conductive medium. In this way, a laminate 35 having the insulating layer 10, the metal support layer 11, and the wiring layer 12 is obtained.

  Subsequently, a plurality of wirings 13a, 13b, 13c and a wiring connection portion 16 are formed in the wiring layer 12, and a metal support layer through hole 31a is formed in the metal support layer 11 (see FIG. 14B). . In this case, a patterned resist (not shown) is formed on the wiring layer 12 by a photofabrication technique, and the wiring layer 12 and the metal support layer are formed from an opening of the resist by a corrosive liquid such as a ferric chloride aqueous solution. 11 is etched. In this way, the wiring layer 12 and the metal support layer through hole 31a having a desired shape are formed. At this time, the head terminal 5 and the tail terminal 6 as shown in FIG. Thereafter, the resist is removed.

  Next, a protective layer 20 having a desired shape is formed on the insulating layer 10 to cover the wirings 13a, 13b, 13c and the wiring connection portion 16 of the wiring layer 12 (see FIG. 14C). In this case, non-photosensitive polyimide is coated on the insulating layer 10 using a die coater, and dried to form the protective layer 20. Subsequently, a patterned resist (not shown) is formed on the formed protective layer 20, and the exposed portion of the protective layer 20 is etched to cure the protective layer 20. In this way, the protective layer 20 having a desired shape is obtained. At this time, an inspection through hole 21 is formed in the protective layer 20. The method for etching the protective layer 20 is not particularly limited, but it is preferable to perform wet etching. In particular, the etching solution is preferably selected as appropriate according to the type of material of the protective layer 20. For example, when the protective layer 20 is formed of a polyimide resin, an alkaline etching solution such as an organic alkaline etching solution is used. Can be used. Thereafter, the resist is removed.

After the protective layer 20 is obtained, the insulating frame portion 18 including the insulating layer through-holes 31b is formed in the insulating layer 10, and the outer shape of the insulating layer 10 is processed into a desired shape (see FIG. 14D). ). In this case, first, a patterned resist (not shown) is formed, and the exposed portion of the insulating layer 10 is etched to form the insulating frame 18 and the outer shape of the insulating layer 10 is processed. Here, the method of etching the insulating layer 10 is not particularly limited as in the method of etching the protective layer 20, but wet etching is preferably performed.
In particular, the etching solution is preferably selected as appropriate according to the type of material of the insulating layer 10. For example, when the insulating layer 10 is formed of a polyimide resin, an alkaline etching solution such as an organic alkaline etching solution is used. Can be used. After the etching is performed, the resist is removed.

  Next, a bonding plating layer 82 is formed (see FIGS. 14E and 14F). That is, as shown in FIGS. 15 and 16, a resist 87 having a resist concavo-convex portion 88 in which the periphery of the resist opening 87a is formed in a concavo-convex shape in plan view is provided on the surface of the metal support layer 11 on the piezoelectric element 44 side. Thus, a plating layer 82 for bonding in which the outer peripheral edge is formed in an uneven shape in plan view is obtained. Here, a method for forming the resist concavo-convex portion 88 on the periphery of the resist opening 87a of the resist 87 will be described in detail below with reference to FIGS. In FIG. 15, for the sake of convenience, the resist formed on the lower surface of the connection structure region 3 is shown, and the resist formed on the upper surface of the connection structure region 3 is omitted.

  First, a water-soluble negative photosensitive resist 87 (preferably a dry film photoresist having a thickness of 38 μm) is laminated on the metal support layer 11 (see FIG. 15A).

  Subsequently, the laminated resist 87 is irradiated with ultraviolet rays from a high-pressure mercury lamp, and the resist 87 is exposed (see FIG. 15B). In this case, the ultraviolet rays are irradiated through an exposure mask 89 having a mask opening 89a having a predetermined shape. In this case, the resist 87 is exposed with a predetermined exposure amount. This exposure amount can be evaluated using, for example, a stove 21-step tablet (Liston (registered trademark) stoffer 21-step tablet manufactured by DuPont).

  The step tablet is a tool for determining an optimum exposure amount to the resist. Specifically, the step tablet has 21 stages in which the optical density increases sequentially, the amount of light that passes through the portion with the lowest optical density, and the light that passes through the portion with the highest optical density. The amount is designed to be the smallest. At the time of exposure, the resist is placed on the upper surface of the resist to be exposed and exposed through a step tablet, so that the resist is irradiated with ultraviolet rays at an exposure amount corresponding to the number of steps, and the resist according to the irradiated exposure amount. Is photocured. By developing after exposure, uncured unexposed portions are removed, but the amount of exposure can be evaluated by confirming the maximum number of steps where the resist remains. That is, the optimum exposure amount can generally vary depending on the type of resist material to be used, but by using a step tablet, the optimum exposure amount can be evaluated regardless of the type of material.

  In the case of using this stove 21 step tablet, it is preferable that the resist 87 is exposed with an exposure amount such that the maximum number of remaining resist steps is 10 to 18 steps. As a result, a resist uneven portion 88 is formed at the periphery of the resist opening 87a (see FIG. 15C) of the resist 87, and uneven portions having a desired uneven height can be formed. In addition, the uneven | corrugated height of the resist uneven | corrugated | grooved part 88 is 0.0015 mm-0.0200 mm similarly to the uneven | corrugated height of the outer periphery uneven | corrugated part 85, It is preferable that it is 0.0015 mm-0.0100 mm especially.

  Thereafter, the exposed resist 87 is spray developed using an aqueous sodium carbonate solution having a concentration of 1 wt%. In this case, the sodium carbonate aqueous solution dissolves or disperses the unexposed portions of the resist 87. Thus, a resist 87 having a predetermined shape from which an unexposed portion is removed is obtained (see FIG. 15C). At this time, irregularities are formed on the periphery of the resist opening 87 a of the resist 87. That is, as shown in FIG. 16, a resist uneven portion 88 including a resist convex portion 88a and a resist concave portion 88b is formed at the periphery of the resist opening 87a of the resist 87.

  After development, the resist 87 is heated. In general, the heat treatment is performed before development, and the periphery of the resist opening 87a of the resist 87 that has become non-uniform due to scattered light is made uniform, and the adhesion of the resist 87 is improved, and the development treatment is performed. Increases later etching resistance and plating resistance. However, in this embodiment, as described above, the resist 87 is heat-treated after development. As a result, the plating resistance after the development process can be improved, and the shape of the resist concavo-convex portion formed on the periphery of the resist opening 87a of the resist 87 can be maintained. In addition, it is suitable to apply a hot-air drying system etc. to heat processing, for example, it is preferable to expose for 20 second or more in the temperature environment of 50 to 160 degreeC.

  In this manner, as shown in FIG. 16, a resist 87 having a predetermined pattern in which a resist unevenness 88 is formed on the periphery of the resist opening 87a is obtained. Thereafter, nickel plating and gold plating are sequentially performed using the obtained resist 87 to form a bonding plating layer 82.

  Of these, the nickel plating layer 83 for bonding is obtained by electrolytic plating after the portion exposed from the resist opening 87a of the resist 87 is acid cleaned (see FIG. 14E). The outer peripheral edge of the obtained bonding nickel plating layer 83 is formed in an uneven shape so as to correspond to the resist uneven portion 88 of the resist 87. When the bonding nickel plating layer 83 is formed, the connection nickel plating layer 33 is formed on the wiring connection portion 16. At this time, nickel plating is similarly applied to the head terminal 5 and the tail terminal 6 (both see FIG. 1), and nickel plating is also applied to the portion exposed by the inspection through hole 21 of the wiring connection portion 16. (That is, the inspection nickel plating layer 23 is formed). The plating method is not limited to the electrolytic plating method, and an immersion plating method, a jig plating method, or the like can also be used.

  Subsequently, a gold plating layer 84 for bonding is obtained by an electrolytic plating method using the resist 87 used when nickel plating is performed (see FIG. 14F). An outer peripheral edge uneven portion 85 is formed on the outer peripheral edge 84a of the obtained bonding gold plating layer 84, and the outer peripheral edge 84a is uneven in a plan view in the same manner as the outer peripheral edge of the bonding nickel plating layer 83 described above. It is formed into a shape. That is, the outer peripheral edge concave portion 85a is formed corresponding to the resist convex portion 88a of the resist 87, and the outer peripheral edge convex portion 85b is formed corresponding to the resist concave portion 88b. When the bonding gold plating layer 84 is formed, the connection gold plating layer 34 is formed on the connection nickel plating layer 33. At this time, the head terminal 5 and the tail terminal 6 (both see FIG. 1) are also plated with gold, and the plated nickel layer 33 for connection on the wiring connection portion 16 is also plated with gold (ie, The gold plating layer 24 for inspection is formed).

  Thereafter, the resist 87 is removed. In this way, the connection plating layer 32 and the bonding plating layer 82 are obtained.

  The surfaces of the formed connection gold plating layer 34 and bonding gold plating layer 84 may be cleaned. For example, the suspension substrate 1 is placed in a vacuum chamber, and argon (Ar) gas is introduced into the vacuum chamber, and argon gas plasma treatment is performed for 1 minute under conditions of a discharge power of 100 W and a frequency of 15 kHz at normal pressure. May be. Thus, the surfaces of the connection gold plating layer 34 and the bonding gold plating layer 84 can be cleaned, and the adhesion between the connection gold plating layer 34 and the bonding gold plating layer 84 and the conductive adhesive is improved. It becomes possible to make it.

  In order to further improve the adhesion between the metal support layer 11 and the bonding gold plating layer 84, the bonding nickel plating layer 83 may be formed as follows. That is, a corresponding portion of the surface of the metal support layer 11 is first subjected to nickel strike plating using a hydrochloric acid-based plating solution to remove the passive film, and then subjected to nickel plating by an electrolytic plating method. It is preferable that the nickel plating layer 83 for bonding is formed. Thus, by performing nickel strike plating, the passive film on the surface of the metal support layer 11 can be removed, and the adhesion between the metal support layer 11 and the nickel plating layer 83 for bonding can be improved. In this case, the nickel strike plating thickness is preferably 0.05 μm to 0.1 μm, and the nickel plating thickness by electrolytic plating is preferably 0.5 μm to 2.5 μm. Alternatively, in order to further improve the adhesion, the nickel strike plating thickness is set to about 0.1 μm, and in order to suppress the formation of pin holes in the bonding nickel plating layer 83, the plating thickness by electrolytic plating is used. Can be set to 0.5 μm to 5.0 μm. In performing the nickel strike plating in the latter case, the plating thickness can be increased by increasing the current value. In the former case, strike plating is performed by reducing the current value (or by shortening the plating time) than in the latter case. In this case, the plating layer 82 for bonding out of the surface of the metal support layer 11 is used. It can suppress that the area | region in which no is formed corrodes. In addition, when performing nickel strike plating, it is suitable that the thickness of the gold plating layer 84 for joining shall be 0.5 micrometer-2.5 micrometers.

  After the connection plating layer 32 and the bonding plating layer 82 are formed, the metal support layer 11 is trimmed to form the metal frame portion 17 (see FIG. 14G). In this case, first, a patterned resist (not shown) is formed on the lower surface of the metal support layer 11 using a dry film. Next, for example, a portion of the metal support layer 11 exposed from the resist is etched with an iron chloride etching solution to form the metal frame body portion 17 and the metal support layer 11 is processed into a desired shape. Is done. The metal frame portion 17 is separated from the main body portion 11 a of the metal support layer 11 in the substrate main body region 2. Thereafter, the resist is removed, and the suspension substrate 1 according to the present embodiment is obtained.

  Next, a suspension manufacturing method using the suspension substrate 1 thus obtained will be described.

  First, the base plate 42 and the load beam 43 are prepared, and the above-described suspension substrate 1 is prepared.

  Next, the suspension substrate 1 is attached to the base plate 42 via the load beam 43 by welding. In this case, first, the load beam 43 is fixed to the base plate 42 by welding, then, a beam jig hole (not shown) provided in the load beam 43 and a jig hole 25 provided in the suspension substrate 1. As a result, the alignment of the load beam 43 and the suspension substrate 1 is performed. Thereafter, the metal support layer 11 of the suspension substrate 1 is welded, and the load beam 43 and the suspension substrate 1 are joined and fixed to each other.

Next, the piezo element 44 is bonded to the base plate 42 and the load beam 43 using an adhesive, and connected to the connection structure region 3 of the suspension substrate 1.
In this case, first, the piezo element 44 is bonded to the base plate 42 and the load beam 43 via the non-conductive adhesive portion 46. Next, a conductive adhesive is applied to form a first conductive adhesive portion 47, and an electrode 44 a on one side (opposite side of the suspension substrate 1) of the piezo element 44 is formed via the first conductive adhesive portion 47. The base plate 42 is electrically connected via a conductive adhesive.

  Further, the other electrode 44a (the suspension substrate 1 side) of the piezo element 44 is joined and electrically connected to the connection structure region 3 of the suspension substrate 1 through the second conductive adhesive portion 48. (See FIG. 11). In this case, the conductive adhesive is pre-injected into the injection hole 31 of the suspension substrate 1, and when the piezoelectric element 44 is joined to the base plate 42 and the load beam 43, the connection structure region 3 becomes one of the piezoelectric elements 44. It is joined and electrically connected to the electrode 44a. Accordingly, the second conductive adhesive portion 48 is bonded not only to the metal frame portion 17 but also to the bonding gold plating layer 84 provided on the metal frame portion 17.

  In this way, the suspension 41 according to the present embodiment is obtained.

  A head slider 52 is connected to the head terminal 5 of the suspension 41 to obtain the suspension with head 51 shown in FIG. Furthermore, the suspension 51 with the head is attached to the arm 66 of the hard disk drive 61, and the FPC board 71 is connected to the tail terminal 6 of the suspension board 1 to obtain the hard disk drive 61 shown in FIG.

  When data is written and read in the hard disk drive 61 shown in FIG. 13, the head slider 52 of the suspension 51 with the head is moved along the disk 63 by the voice coil motor 65, and the disk 63 rotated by the spindle motor 64 is rotated. Keep close to the desired flying height. As a result, data is exchanged between the head slider 52 and the disk 63. During this time, an electrical signal is transmitted between the control unit (not shown) connected to the FPC board 71 and the head slider 52 via the suspension board 1 and the FPC board 71. Such an electrical signal is transmitted between the head terminal 5 (see FIG. 1) and the tail terminal 6 through the signal wirings 13a in the suspension board 1.

  When moving the head slider 52, the voice coil motor 65 roughly adjusts the position of the head slider 52, and the piezo element 44 finely adjusts the position of the head slider 52. That is, by applying a predetermined voltage to the electrode 44a of the piezoelectric element 44 on the connection structure region 3 side of the suspension substrate 1, the direction along the longitudinal axis (X) (the direction of the arrow P in FIGS. 8 and 12). In addition, one piezo element 44 contracts and the other piezo element 44 expands. In this case, the flexible portion 42b of the base plate 42 and the flexible portion 43c of the load beam 43 are elastically deformed, and the head slider 52 located on the tip side of the load beam 43 moves in the sway direction (turning direction Q). it can. Note that the voltage applied to the electrode 44 a of the piezo element 44 is input to the electrode 44 a via the element wiring 13 b, the wiring connection portion 16, and the second conductive adhesive portion 48. In this way, the head slider 52 can be quickly and accurately aligned with a desired track of the disk 63.

  Thus, according to the present embodiment, the bonding gold plating layer 84 to be bonded to the conductive adhesive is provided on the surface of the metal support layer 11 on the piezoelectric element 44 side, and the bonding gold plating layer 84 is provided. An outer peripheral uneven portion 85 is formed on the outer peripheral edge 84a, and the outer peripheral edge 84a is formed in an uneven shape in plan view. Thereby, the conductive particles (for example, silver filler 49b) of the conductive adhesive can enter the outer peripheral concavo-convex portion 85 and come into contact therewith, and the bonding reliability between the bonding gold plating layer 84 and the conductive adhesive. Can be improved. Further, the contact area between the bonding gold plating layer 84 and the conductive adhesive can be increased, and this also improves the bonding reliability between the bonding gold plating layer 84 and the conductive adhesive. . For this reason, the electrical connection between the connection structure region 3 and the conductive adhesive can be stabilized, and the reliability of the electrical connection with the piezo element 44 can be improved.

  Moreover, according to this Embodiment, in the connection structure area | region 3, a conductive adhesive is inject | poured into the injection hole 31 which has the metal support layer through-hole 31a and the insulating layer through-hole 31b. Thereby, the joint reliability between the connection structure region 3 and the conductive adhesive can be improved by the anchor effect. For this reason, the electrical connection between the connection structure region 3 and the conductive adhesive can be stabilized, and the reliability of the electrical connection with the piezo element 44 can be improved.

  Although the embodiments of the present invention have been described in detail, the suspension substrate, the suspension, the suspension with a head, the hard disk drive, and the suspension substrate manufacturing method according to the present invention are not limited to the above-described embodiments. Instead, various modifications can be made without departing from the spirit of the present invention, and the following modifications can be combined as appropriate.

  Hereinafter, modifications of the embodiment of the present invention will be described with reference to FIGS. 17 to 26, the same parts as those in the embodiment shown in FIGS. 1 to 16 are denoted by the same reference numerals, and detailed description thereof is omitted.

(Modification 1)
In the above-described embodiment, the example in which the suspension substrate 1 is manufactured by the subtractive method and the wiring connection portion 16 is formed on the insulating layer through-hole 31b has been described. However, the present invention is not limited to this, and the suspension substrate 1 may be manufactured by an additive method. In this case, as shown in FIG. 17, a part of the wiring connection portion 16 is embedded in the insulating layer through hole 31b. In this case, the wiring connection portion 16 is exposed by the metal support layer through hole 31a, and the conductive adhesive is not injected into the insulating layer through hole 31b, but is injected into the metal support layer through hole 31a. That is, the conductive adhesive is injected into a part of the injection hole 31 (metal support layer through hole 31a) constituted by the metal support layer through hole 31a and the insulating layer through hole 31b. In this case, the amount of the conductive adhesive used can be reduced, and the conductive adhesive can be prevented from protruding around the connection structure region 3.

(Modification 2)
In the embodiment described above, an example in which the bonding plating layer 82 including the bonding gold plating layer 84 extends to the through hole defining surface 17a of the metal frame body portion 17 forming the metal support layer through hole 31a. explained. However, the present invention is not limited to this. As shown in FIG. 18, the bonding plating layer 82 may be provided only on the surface of the metal frame portion 17 on the piezoelectric element 44 side. In this case, the bonding plating layer 82 is preferably formed in a ring shape so as to surround the injection hole 31 in a plan view together with the bonding nickel plating layer 83, as shown in FIG. In this case, the bonding gold plating layer 84 has an inner peripheral edge uneven portion 90 (preferably plural) formed in an uneven shape in a plan view provided on the inner peripheral edge 84b. Is preferred. As a result, the bonding reliability between the bonding gold plating layer 84 and the conductive adhesive can be further improved. In this case, it is preferable that the inner peripheral edge of the bonding nickel plating layer 83 is also formed in an uneven shape in plan view in the same shape as the bonding gold plating layer 84.

  The inner peripheral uneven portion 90 includes an inner peripheral recessed portion 90a that is recessed inward in a plan view and an inner peripheral protruded portion 90b that protrudes outward in a plan view, and is uneven in a plan view so that the silver filler 49b can enter. It is formed in a shape. The uneven height of the inner peripheral uneven portion 90 is preferably 0.0015 mm to 0.0200 mm, particularly preferably 0.0015 mm to 0.0100 mm, similar to the uneven height of the outer peripheral uneven portion 85. The uneven height of the inner peripheral uneven portion 90 is the same as the uneven height of the outer peripheral uneven portion 85, and the distance between the valley line of the inner peripheral recessed portion 90a and the peak line of the inner peripheral protruded portion 90b is measured. The measured interval can be the height of the unevenness.

(Modification 3)
In the above-described embodiment, the surface of the wiring connection portion 16 on the side of the piezo element 44 is exposed by the injection hole 31 provided in the metal support layer 11 and the insulating layer 10, and a conductive adhesive is applied to the injection hole 31. The example in which the wiring connection portion 16 is electrically connected to the piezo element 44 through the conductive adhesive by being injected has been described. However, the present invention is not limited to this. As shown in FIG. 20, the surface of the wiring connection portion 16 on the side of the piezo element 44 is covered with the metal support connection portion 94 of the insulating layer 10 and the metal support layer 11. The wiring connection portion 16 and the metal support connection portion 94 may be connected by a conductive connection portion 95 that penetrates the insulating layer 10. In this case, the metal support connection portion 94 can function as an electrode, and the voltage applied to the electrode 44a of the piezo element 44 includes element wiring 13b, wiring connection portion 16, conductive connection portion 95, metal support connection portion 94, and The signal is input to the electrode 44 a through the second conductive adhesive portion 48. The metal support connection portion 94 is formed in an island shape, and is separated from the main body portion 11a of the metal support layer 11 in the substrate main body region 2 and is electrically insulated.

  More specifically, an insulating layer conductive connection hole 95 a that penetrates the insulating layer 10 is provided, a wiring layer conductive connection hole 95 b that penetrates the wiring connection portion 16, and a protective layer conductive connection hole that penetrates the protective layer 20. 95c is provided, and the conductive connection portion 95 is formed by performing nickel plating on the insulating layer conductive connection hole 95a, the wiring layer conductive connection hole 95b, and the protective layer conductive connection hole 95c. The conductive connection part 95 shown in FIG. 20 is exposed to the outside opposite to the metal support connection part 94, that is, outward from the protective layer 20. For this reason, by using a continuity tester such as a probe, the continuity test between the conductive connection portion 95 and the piezo element 44 can be performed from the upper surface of the conductive connection portion 95. In addition, the conductive connection part 95 is not restricted to the form shown in FIG. 20, The wiring connection part 16 and the conductive connection part 95 may be integrally formed with the same material by an additive method. In this case, the conductive connection portion 95 is covered with the protective layer 20.

  In Modification 3 shown in FIG. 20, since the metal support layer through-hole 31a is not formed in the metal support layer 11 in the connection structure region 3, the bonding gold plating layer 84 can be formed in a circular shape. As a result, the contact area between the bonding gold plating layer 84 and the conductive adhesive can be increased, and the contact resistance between the bonding gold plating layer 84 and the conductive adhesive can be reduced. Further, the conductive gold adhesive layer 84 is also bonded to the outer peripheral edge uneven portion 85 of the bonding gold plating layer 84 by conductive particles of the conductive adhesive (for example, silver filler 49b) coming into contact therewith. Contact resistance with the agent can be reduced. For this reason, the electrical connection between the connection structure region 3 and the piezoelectric element 44 can be stabilized, and the reliability of the electrical connection between the suspension substrate 1 and the piezoelectric element 44 can be improved.

(Modification 4)
In Modification 3 described above, the example in which the bonding gold plating layer 84 is formed in a circular shape has been described. However, the present invention is not limited to this, and as shown in FIGS. 21 and 22, the bonding gold plating layer 84 may be formed in a ring shape in plan view. In this case, it is preferable that the gold plating layer 84 for bonding has an inner peripheral uneven portion 90 (preferably a plurality) formed in an uneven shape in plan view provided on the inner peripheral edge 84b. is there. As a result, the bonding reliability between the bonding gold plating layer 84 and the conductive adhesive can be further improved, and the electrical connection between the connection structure region 3 and the piezo element 44 can be stabilized. In this case, the inner peripheral edge of the bonding nickel plating layer 83 has the same shape as that of the bonding gold plating layer 84 and is formed in an uneven shape in plan view.

  The inner peripheral uneven portion 90 includes an inner peripheral recessed portion 90a that is recessed inward in a plan view and an inner peripheral protruded portion 90b that protrudes outward in a plan view, and is uneven in a plan view so that the silver filler 49b can enter. It is formed in a shape. The uneven height of the inner peripheral uneven portion 90 is preferably 0.0015 mm to 0.0200 mm, particularly preferably 0.0015 mm to 0.0100 mm, similar to the uneven height of the outer peripheral uneven portion 85. The uneven height of the inner peripheral uneven portion 90 is the same as the uneven height of the outer peripheral uneven portion 85, and the distance between the valley line of the inner peripheral recessed portion 90a and the peak line of the inner peripheral protruded portion 90b is measured. The measured interval can be the height of the unevenness.

(Modification 5)
Further, in the above-described modifications 3 and 4, the bonding plating layer 82 has a plurality (for example, three) of bonding plating layer divisions 96 separated from each other, and each of the bonding plating layer divisions 96. However, for example, as shown in FIG. 23, it may be formed in a circular shape in plan view. In this case, each plating layer division body 96 for bonding has an outer peripheral uneven portion 85 (see FIGS. 4 and 5) provided on the outer peripheral edge 96a and formed in an uneven shape in plan view. As a result, the bonding reliability between each bonding plating layer divided body 96 and the conductive adhesive can be further improved, and the electrical connection between the connection structure region 3 and the piezo element 44 can be stabilized. .

(Modification 6)
In the present embodiment described above, as shown in FIG. 24, the wiring connection portion 16 and the metal frame portion 17 are connected by the same conductive connection portion 95 as that of the third modification shown in FIG. Also good. In this case, the route in which the wiring connection portion 16 is electrically connected to the second conductive adhesive portion 48 via the connection plating layer 32, and the wiring connection portion 16 include the conductive connection portion 95 and the metal frame portion 17. And a route electrically connected to the second conductive adhesive portion 48 via the bonding plating layer 82.

  In the modification 6 shown in FIG. 24, as described above, the wiring connection portion 16 is electrically connected directly (more specifically, via the connection plating layer 32) to the second conductive adhesive portion 48. At the same time, they are electrically connected via the conductive connection portion 95, the metal frame portion 17, and the bonding plating layer 82. Thereby, the electrical resistance between the wiring connection portion 16 and the second conductive adhesive portion 48 can be reduced. Further, the conductive gold adhesive layer 84 is also bonded to the outer peripheral edge uneven portion 85 of the bonding gold plating layer 84 by conductive particles of the conductive adhesive (for example, silver filler 49b) coming into contact therewith. Contact resistance with the agent can be reduced. Furthermore, since the bonding plating layer 82 extends to the through hole defining surface 17a of the metal support layer 11, the contact area between the bonding plating layer 82 and the second conductive adhesive portion 48 can be increased. For this reason, the electrical connection between the connection structure region 3 and the piezoelectric element 44 can be stabilized, and the reliability of the electrical connection between the suspension substrate 1 and the piezoelectric element 44 can be improved.

(Modification 7)
In the present embodiment described above, the bonding gold plating layer 84 is provided on the surface of the metal frame 17 on the piezoelectric element 44 side, and the bonding gold plating layer 84 is formed on the outer peripheral edge 84a. The example which provided the outer periphery uneven | corrugated | grooved part 85 formed in uneven | corrugated shape by planar view provided was demonstrated. However, the present invention is not limited to this, and as shown in FIG. 25, the connection gold plating layer 34 provided in the wiring connection portion 16 is formed in an uneven shape in plan view provided on the outer peripheral edge 34a. You may have the outer periphery uneven | corrugated | grooved part 85 (refer FIG. 4 and FIG. 5) made. In this case, the connection nickel plating layer 33 interposed between the wiring connection portion 16 and the connection gold plating layer 34 covers the entire surface of the wiring connection portion 16 exposed by the injection hole 31. preferable. Thereby, corrosion of the surface exposed by the insulating layer through-hole 31b of the wiring connection portion 16 can be prevented. The connection gold plating layer 34 is formed smaller than the connection nickel plating layer 33, and the outer peripheral side region of the connection nickel plating layer 33 is exposed to the piezoelectric element 44 side.

  In the modified example 7, the bonding reliability between the connection gold plating layer 34 and the conductive adhesive can be improved by the outer peripheral uneven portion 85 formed on the outer peripheral edge 34 a of the connection gold plating layer 34. In this case, conductive particles (for example, silver filler 49b) of the conductive adhesive enter and contact the outer peripheral concavo-convex portion 85. As a result, the contact resistance between the connection gold plating layer 34 and the conductive adhesive can be reduced, and the electrical connection between the connection structure region 3 and the piezo element 44 can be stabilized. For this reason, the reliability of the electrical connection between the suspension substrate 1 and the piezo element 44 can be improved.

(Modification 8)
Further, in the present embodiment described above, when exposing the resist 87 for plating (see FIGS. 15 and 16), the irradiation amount of ultraviolet rays is increased to form irregularities on the periphery of the resist opening 87a of the resist 87. And the example in which the outer periphery uneven | corrugated | grooved part 85 was formed in the outer periphery 84a of the gold plating layer 84 for joining was demonstrated. However, the present invention is not limited to this, and as shown in FIG. 26, a mask concave portion 97a and a mask convex portion 97b are included at the periphery of the mask opening 89a of the exposure mask 89 used when the resist 87 for plating is exposed. The mask concavo-convex portion 97 may be formed, and the peripheral edge may be formed in a concavo-convex shape in advance. By using such an exposure mask 89, unevenness can be formed at the periphery of the resist opening 87a of the resist 87 even when the exposure is performed with a normal irradiation amount without increasing the irradiation amount of ultraviolet rays. The uneven height H2 of the mask uneven portion 97 of the exposure mask 89 is preferably 0.005 mm to 0.020 mm, and more preferably 0.005 mm to 0.010 mm. By setting the thickness to 0.005 mm or more, the exposure mask 89 having the mask concave portion 97a and the mask convex portion 97b is manufactured even when the drawing machine for manufacturing the exposure mask 89 is set to the normal drawing resolution. The number of mask concave portions 97a and mask convex portions 97b can be increased by setting the thickness to 0.020 mm or less, particularly 0.010 mm or less.

  By using the resist 87 formed in this manner, the outer peripheral uneven portion 85 can be formed on the outer peripheral edge 84 a of the bonding gold plating layer 84. In this case, the uneven height of the outer peripheral uneven portion 85 is the same as the uneven height of the mask uneven portion 97 described above.

  Based on the above-described embodiment, the outer peripheral edge of the bonding gold plating layer 84 formed by forming the resist 87 for forming the bonding gold plating layer 84 while performing the plating process while changing the exposure amount. The uneven height of the uneven portion 85 was measured. Here, the above-described stofa 21-step tablet was used for the evaluation of the exposure amount.

  In this embodiment, when exposing the resist 87, a step tablet was placed on the resist 87, and the resist 87 was irradiated with ultraviolet rays through the step tablet for exposure. Thereafter, development and heat treatment were performed, and nickel plating and gold plating were sequentially performed to form an outer peripheral uneven portion 85. When the uneven height of the formed outer peripheral uneven portion 85 was measured, data as shown in Table 1 was obtained.

  In addition, the uneven | corrugated height shown in Table 1 has shown the average value. Here, in the same manner as in the present embodiment described above, the uneven height of the outer peripheral uneven portion was measured at any 15 locations, the average value thereof was calculated, and Table 1 was obtained.

  As shown in Table 1, it can be seen that the uneven height increases as the number of steps of the step tablet increases. That is, the increase in the number of steps of the step tablet means that the exposure amount of the ultraviolet rays irradiated from the exposure machine is increasing, and it can be seen that the unevenness height increases as the exposure amount increases. . Further, as shown in FIG. 7, since most of the length of the silver filler 49b of the silver paste 49 is 0.0015 mm or less, Table 1 shows that at least 10 steps of the step tablet include the resist 87. It can be seen that by exposing the resist 87 so as to have the maximum number of remaining steps, the height of the unevenness that allows most of the silver filler 49b in the silver paste 49 to enter and come into contact is obtained.

DESCRIPTION OF SYMBOLS 1 Suspension board | substrate 2 Substrate body area | region 2a Head area | region 2b Tail area | region 3 Connection structure area | region 4 Connection area | region 5 Head terminal 6 Tail terminal 10 Insulating layer 11 Metal support layer 11a Main body part 11b Metal support wiring part 12 Wiring layer 13a Signal wiring 13b Element Wiring 13c Grounding wiring 16 Wiring connection portion 17 Metal frame portion 17a Through hole defining surface 18 Insulating frame portion 20 Protective layer 21 Inspection through hole 22 Inspection plating layer 23 Inspection nickel plating layer 24 Inspection gold plating layer 25 Tool hole 27 Wiring via 28 Ground via 31 Injection hole 31a Metal support layer through hole 31b Insulating layer through hole 32 Connection plating layer 33 Connection nickel plating layer 34 Connection gold plating layer 34a Outer peripheral edge 35 Laminate 41 Suspension 42 Base plate 42a Head side plate 42b Tail side plate 42c Flexible portion 4 d Housing opening 43 Load beam 43a Head side beam 43b Tail side beam 43c Flexible part 43d Exposed opening 44 Piezo element 44a Electrode 44b Piezoelectric material part 46 Non-conductive adhesive part 47 First conductive adhesive part 48 Second conductive Bonding part 49 Silver paste 49a Binder base 49b Silver filler 51 Suspension with head 52 Head slider 61 Hard disk drive 62 Case 63 Disk 64 Spindle motor 65 Voice coil motor 66 Arm 71 FPC board 82 Bonding plating layer 83 Bonding nickel plating layer 84 Gold plating layer for bonding 84a Outer peripheral edge 84b Inner peripheral edge 85 Outer peripheral edge concave / convex part 85a Outer peripheral edge concave part 85b Outer peripheral edge convex part 87 Resist 87a Resist opening 88 Resist concave / convex part 88a Resist convex part 88b Resist concave part 89 Exposure mask 89 Mask opening 90 Inner peripheral edge uneven part 90a Inner peripheral edge concave part 90b Inner peripheral edge convex part 94 Metal support connection part 95 Conductive connection part 95a Insulating layer conductive connection hole 95b Wiring layer conductive connection hole 95c Protective layer conductive connection hole 96 Plating layer divided body 96a Outside Peripheral edge 97 Mask uneven part 97a Mask concave part 97b Mask convex part

Claims (10)

In the suspension substrate having a connection structure region that can be connected to the actuator element via a conductive adhesive containing conductive particles,
An insulating layer;
A metal support layer provided on a surface of the insulating layer on the actuator element side;
A wiring layer provided on a surface of the insulating layer opposite to the actuator element, wherein the wiring layer is provided in the connection structure region, and is connected to the corresponding wiring and connected to the actuator element. A wiring connection portion electrically connected via a conductive adhesive, and the wiring layer having,
A gold plating layer to be bonded to the conductive adhesive is provided on the surface of the metal support layer on the actuator element side,
The gold plating layer has an outer peripheral concavo-convex portion formed on the outer peripheral edge, formed in an uneven shape in plan view,
In the connection structure region, a metal support layer through-hole penetrating the metal support layer and an insulating layer through-hole penetrating the insulating layer are provided,
A part of the wiring connection portion is embedded in the insulating layer through hole ,
The suspension substrate according to claim 1, wherein the uneven height of the outer peripheral uneven portion is 0.0015 mm to 0.0200 mm .   The gold plating layer is formed in a ring shape so as to surround the metal support layer through-hole in a plan view, and the gold plating layer is provided on the inner periphery of the inner periphery. The suspension substrate according to claim 1, wherein the suspension substrate has an uneven portion.   The suspension substrate according to claim 1 or 2, wherein the metal support layer in the connection structure region is electrically insulated from the wiring connection portion. In the suspension substrate having a connection structure region that can be connected to the actuator element via a conductive adhesive containing conductive particles,
An insulating layer;
A metal support layer provided on a surface of the insulating layer on the actuator element side;
A wiring layer provided on a surface of the insulating layer opposite to the actuator element, wherein the wiring layer is provided in the connection structure region, and is connected to the corresponding wiring and connected to the actuator element. A wiring connection portion electrically connected via a conductive adhesive, and the wiring layer having,
A gold plating layer to be bonded to the conductive adhesive is provided on the surface of the metal support layer on the actuator element side,
The gold plating layer has an outer peripheral concavo-convex portion formed on the outer peripheral edge, formed in an uneven shape in plan view,
The wiring connection portion and the metal support layer are connected by a conductive connection portion that penetrates the insulating layer,
A surface of the wiring connection portion on the actuator element side is covered with the insulating layer and the metal support layer,
The gold plating layer has a plurality of gold plating layer segments separated from each other,
The outer peripheral uneven portion is provided on each outer peripheral edge of the gold plating layer divided body ,
The suspension substrate according to claim 1, wherein the uneven height of the outer peripheral uneven portion is 0.0015 mm to 0.0200 mm .   The suspension substrate according to claim 4, wherein the gold plating layer divided body is formed in a circular shape in a plan view. A base plate;
The suspension substrate according to any one of claims 1 to 5 , attached to the base plate via a load beam;
The suspension comprising: the actuator element joined to at least one of the base plate and the load beam, and connected to the connection structure region of the suspension substrate via the conductive adhesive. . The suspension according to claim 6 ;
A suspension with a head, comprising: a head slider mounted on the suspension. A hard disk drive comprising the suspension with a head according to claim 7 . In the manufacturing method of a suspension substrate having a connection structure region connectable to the actuator element via a conductive adhesive containing conductive particles,
Preparing a laminate having an insulating layer, a metal support layer provided on one surface of the insulating layer, and a wiring layer provided on the other surface of the insulating layer;
In the wiring layer, a plurality of wirings, a wiring connection portion provided in the connection structure region, connected to the corresponding wiring, and electrically connected to the actuator element via the conductive adhesive, Forming a
Forming a gold plating layer bonded to the conductive adhesive on the surface of the metal support layer on the actuator element side, and
In the step of forming the gold plating layer, gold plating is performed using a resist having a resist concavo-convex portion in which a peripheral edge of a resist opening is formed in a concavo-convex shape in a plan view on the surface of the metal support layer on the actuator element side. Applied, thereby forming an outer peripheral uneven portion formed in an uneven shape in plan view on the outer peripheral edge of the formed gold plating layer,
In the connection structure region, a metal support layer through-hole penetrating the metal support layer and an insulating layer through-hole penetrating the insulating layer are provided,
A part of the wiring connection portion is embedded in the insulating layer through hole ,
The manufacturing method of a suspension substrate, wherein the unevenness height of the outer peripheral unevenness part is 0.0015 mm to 0.0200 mm . In the manufacturing method of a suspension substrate having a connection structure region connectable to the actuator element via a conductive adhesive containing conductive particles,
Preparing a laminate having an insulating layer, a metal support layer provided on one surface of the insulating layer, and a wiring layer provided on the other surface of the insulating layer;
In the wiring layer, a plurality of wirings, a wiring connection portion provided in the connection structure region, connected to the corresponding wiring, and electrically connected to the actuator element via the conductive adhesive, Forming a
Forming a gold plating layer bonded to the conductive adhesive on the surface of the metal support layer on the actuator element side, and
In the step of forming the gold plating layer, gold plating is performed using a resist having a resist concavo-convex portion in which a peripheral edge of a resist opening is formed in a concavo-convex shape in a plan view on the surface of the metal support layer on the actuator element side. Applied, thereby forming an outer peripheral uneven portion formed in an uneven shape in plan view on the outer peripheral edge of the formed gold plating layer,
The wiring connection portion and the metal support layer are connected by a conductive connection portion that penetrates the insulating layer,
A surface of the wiring connection portion on the actuator element side is covered with the insulating layer and the metal support layer,
The gold plating layer has a plurality of gold plating layer segments separated from each other,
The outer peripheral uneven portion is provided on each outer peripheral edge of the gold plating layer divided body ,
The manufacturing method of a suspension substrate, wherein the unevenness height of the outer peripheral unevenness part is 0.0015 mm to 0.0200 mm .