JP6160916B2 - Suspension board, suspension, suspension with head and hard disk drive - Google Patents

Description

  The present invention relates to a suspension substrate, a suspension, a suspension with a head, and a hard disk drive. In particular, the displacement of the actuator element in the expansion / contraction direction is suppressed, and a pair of electrodes of the actuator element is prevented from being short-circuited. The present invention relates to a suspension substrate, a suspension, a suspension with a head, and a hard disk drive capable of improving the bonding strength.

  2. Description of the Related Art Generally, a hard disk drive (HDD) includes a suspension substrate (flexure) on which a magnetic head slider (hereinafter simply referred to as a head slider) for writing and reading data to and from a disk storing data is mounted. Yes. The suspension substrate is formed so as to extend from a head region where the head slider is mounted to a tail region connected to an FPC substrate (flexible printed circuit board). An insulating layer is provided on the metal support layer and the metal support layer. And a wiring layer having a plurality of wirings stacked on each other, and data is written to or read from the disk by flowing an electric signal through each wiring.

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

  In recent years, there has been an increasing demand for an increase in disk capacity. In order to meet this demand, the density of the disk is increased and the width of the track is reduced. For this reason, it may be difficult to accurately align the head slider with a desired track by the VCM actuator.

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

  However, in the suspension shown in Patent Document 1, the piezo element is mounted on a relatively thick base plate. As a result, there is a problem that the thickness of the piezo element increases and the cost of the piezo element increases. Further, when the thickness of the piezo element increases, the mass of the piezo element increases. For this reason, while the disk is rotating in the hard disk drive, there is also a problem that the vibration characteristics of the suspension that vibrates due to the turbulence (wind turbulence) caused by the rotation of the disk deteriorates. Further, in this case, there is a problem that the shock resistance at the time of suspension loading (when starting to move) and unloading (when retracting) is lowered.

  In order to cope with such a situation, as shown in Patent Documents 2 and 3, a suspension in which a piezoelectric element is mounted on a head region of a suspension substrate has been proposed. In this case, the thickness of the piezo element can be reduced. Further, in this case, since the piezo element can be arranged in the vicinity of the head slider, it is possible to improve the accuracy of positioning of the head slider. In particular, since the piezo element is disposed below the head slider, it is possible to further improve the alignment accuracy of the head slider.

  The connection pad of such a piezo element is soldered to the connection pad of the conductor layer. Here, the solder is accommodated in an opening provided in an insulating layer interposed between the conductor layer and the piezoelectric element.

JP 2002-50140 A JP 2010-146631 A JP 2012-99204 A

  When soldering a piezo element, the piezo element is accurately positioned by utilizing the self-alignment effect of molten solder. For example, when the self-alignment effect is used for positioning in the expansion / contraction direction of the piezo element, the outer edge of the piezo element in the expansion / contraction direction that defines the rectangular opening of the insulating layer is the expansion / contraction direction of the corresponding rectangular piezo element. It arrange | positions in the position which overlaps with the edge of (longitudinal direction) planarly. Thus, when the solder for connecting the pair of electrodes of the piezo element is melted, the surface tension of the melted solder acts on the corresponding electrode of the piezo element, and a self-alignment effect works on the piezo element. That is, the edge of the opening of the insulating layer restricts the piezo element from being displaced in the expansion / contraction direction, and the displacement of the piezo element in the expansion / contraction direction is suppressed.

  However, in this case, the opening of the insulating layer does not protrude to the outside of the piezoelectric element from the end in the expansion / contraction direction of the mounted piezoelectric element. This makes it difficult to form a solder fillet on the outer side of the piezo element in the expansion / contraction direction, and there is a problem that the bonding strength of the piezo element with solder may be insufficient.

  By the way, in order to improve the bonding strength of the piezo element, the width w1 of the opening 201 of the insulating layer 200 is made larger than the width w2 of the piezo element 210 as shown in FIG. A measure of forming a solder fillet 220 is also conceivable. However, since the pair of electrodes of the piezo element 210 are exposed on the side surfaces of the piezo element 210, when the solder fillet 220 is formed on the outer side in the width direction of the piezo element 210, the pair of electrodes of the piezo element 210 are short-circuited. There is a risk of short circuit.

  The present invention has been made in consideration of such points, and suppresses displacement of the actuator element in the expansion / contraction direction and prevents the pair of electrodes of the actuator element from short-circuiting, thereby increasing the bonding strength of the actuator element. An object is to provide a suspension substrate, a suspension, a suspension with a head, and a hard disk drive that can be improved.

  The present invention is a suspension substrate on which a head slider and a pair of electrodes that can be connected using a solder member, and an expandable / contractible actuator element that displaces the head slider are mounted. And an insulating layer provided on the metal support layer, and a wiring layer provided on the insulating layer and having an element connection terminal connected to the electrode of the actuator element via the solder member. The metal support layer is provided with a receiving opening for receiving the actuator element, and the insulating layer exposes the element connection terminal to the receiving opening and the first terminal opening for receiving the solder member. When the actuator element is mounted on the outer edge of the first terminal opening in the direction of expansion and contraction of the actuator element. The second terminal opening extends from the end of the first terminal opening to the outside of the actuator element and is disposed at a position overlapping the end of the actuator element in the expansion / contraction direction in plan view. Provided is a suspension substrate, wherein the suspension terminal communicates with the opening, and the width of the second terminal opening is smaller than the width of the first terminal opening and smaller than the width of the actuator element to be mounted. .

  In the suspension substrate described above, the second terminal opening may be formed in a rectangular shape in plan view.

  In the suspension substrate described above, the second terminal opening may be tapered toward the outside of the actuator element in the expansion / contraction direction in a plan view.

  In the suspension substrate described above, a plurality of the second terminal openings may be provided.

  In the suspension substrate described above, the width of the first terminal opening may be not less than 80% and not more than 120% of the width of the actuator element to be mounted.

  In the suspension substrate described above, the width of the first terminal opening may be 96% or more of the width of the actuator element to be mounted.

  In the suspension substrate described above, the width of the first terminal opening may be the same as the width of the actuator element to be mounted.

  The present invention comprises the above-described suspension substrate and the actuator element mounted on the suspension substrate, and the electrode of the actuator element is inserted through the solder member accommodated in the terminal opening. A suspension characterized by being connected to an element connection terminal.

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

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

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing the position shift in the expansion / contraction direction of an actuator element, it can prevent that a pair of electrode of an actuator element short-circuits, and can improve the joint strength of an actuator element.

FIG. 1 is a plan view showing an example of a suspension with a head according to an embodiment of the present invention. FIG. 2 is an enlarged plan view showing a head region in the suspension with a head shown in FIG. FIG. 3 is a view showing a side surface of the piezoelectric element mounted on the suspension board of FIG. FIG. 4 is a partial cross-sectional view showing the head region of FIG. FIG. 5 is a view taken in the direction of arrow A in FIG. 6 is a plan view showing the terminal opening shown in FIG. 7 is a cross-sectional view taken along line BB in FIG. FIG. 8 is a perspective view showing an example of a hard disk drive including the suspension with a head shown in FIG. FIGS. 9A to 9C are diagrams for explaining a mounting method of the piezoelectric element in the embodiment of the present invention. FIG. 10 is a diagram for explaining the positional deviation amount of the piezoelectric element in the step of FIG. 9C. FIG. 11 is a graph showing the amount of deviation of the piezoelectric element in the example of the present invention. 12A to 12C are diagrams showing a modification of FIG. FIG. 13 is a diagram for explaining a case where a solder fillet is formed on the outer side of the piezoelectric element in the width direction.

  A suspension substrate, a suspension, a suspension with a head, and a hard disk drive 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 with head 111 includes a suspension 101 and a head slider 112 mounted on the head region 2 of the suspension substrate 1. Of these, the head slider 112 is for writing and reading data on a disk 123 (see FIG. 8) described later, and is bonded to the head region 2 of the suspension substrate 1 described later using an adhesive. ing. A slider terminal (not shown) of the head slider 112 is electrically connected to the head terminal 41 by a slider solder member.

  The suspension 101 includes a base plate 102, a load beam 103 attached on the base plate 102, a suspension substrate 1 attached to the load beam 103, and a pair of piezo elements (mounted on the head region 2 of the suspension substrate 1). Actuator element) 104. Of these, the base plate 102 and the load beam 103 are both preferably made of stainless steel and are fixed to each other by welding.

  The load beam 103 is attached to the metal support layer 20 (described later) of the suspension substrate 1 by welding. The load beam 103 is provided with a jig hole (not shown), and the suspension substrate 1 is aligned with the jig hole of the load beam 103 as shown in FIG. A jig hole 5 for performing the above is provided. Thus, when the load beam 103 is attached to the suspension substrate 1, the suspension substrate 1 and the load beam 103 can be aligned. The jig hole of the load beam 103 and the jig hole 5 of the suspension substrate 1 are arranged on the longitudinal axis (X) shown in FIG.

  As shown in FIGS. 1 and 2, the piezo element 104 is configured to be extendable and contractible in the longitudinal direction (P direction in FIG. 2). As a result, the pair of piezo elements 104 can displace the head slider 112 in the sway direction (the turning direction, the arrow Q direction in FIG. 2).

  Here, the structure of the piezoelectric element 104 will be described more specifically. As shown in FIG. 3, the piezo element 104 includes a pair of electrodes (first electrode 104a and second electrode 104b) and a piezoelectric material portion 104c made of piezoelectric ceramics such as PZT (lead zirconate titanate). Have. Each of the electrodes 104a and 104b includes connection pads (first connection pads 104d and second connection pads 104e) connected to element connection terminals 45 and 46, which will be described later, of the suspension substrate 1, respectively. The pair of connection pads 104d and 104e are formed at both ends in the expansion / contraction direction (longitudinal direction) on the surface of the piezoelectric material portion 104c on the insulating layer 10 side, and are accommodated in terminal openings 11 and 12 of the insulating layer 10 described later. It is connected to the element connection terminals 45 and 46 through the solder member 105 (see FIG. 4).

  Each of the electrodes 104a and 104b extends in the expansion / contraction direction from one end of the piezo element 104 to the other end, and is formed so that a predetermined gap is interposed between the one electrode 104a and the other electrode 104b. Has been. The material of the piezoelectric material portion 104c is interposed between the electrodes 104a and 104b. The electrodes 104a and 104b also extend in the planar direction of the piezo element 104, and are exposed to the outside at side surfaces 104f and 104g (see FIG. 5) of the piezo element 104. That is, the electrodes 104 a and 104 b including the connection pads 104 d and 104 e are formed over the entire width of the piezoelectric element 104, and the widths of the connection pads 104 d and 104 e are the same as the width of the piezoelectric element 104.

  By the way, the piezoelectric material portions 104c of the pair of piezoelectric elements 104 are formed to have polarization directions different from each other by 180 °, and when a predetermined voltage is applied, one piezoelectric element 104 contracts and the other piezoelectric element 104c contracts. The piezo element 104 is extended. That is, the piezo element 104 is configured as a piezoelectric element that can expand and contract in the direction of arrow P in FIG. 2 when a predetermined voltage is applied between the electrodes 104a and 104b.

  As shown in FIG. 1, such a piezo element 104 is formed in an elongated rectangular shape along the longitudinal axis (X), and its expansion / contraction direction is parallel to the longitudinal axis (X). ing. The piezo elements 104 are arranged symmetrically with respect to the longitudinal axis (X) so that the expansion and contraction of each piezo element 104 is evenly transmitted to the head slider 112.

  It is preferable to use a material having a low melting point for the solder member 105. Accordingly, when heating to melt the solder member, the heating temperature can be reduced, and the polarization of the piezoelectric material portion 104c can be prevented from disappearing due to the temperature of the piezo element 104 rising. Such a solder member is preferably formed of, for example, an Sn—Bi solder material containing Sn (tin) and Bi (bismuth). By containing Bi, the melting point of the solder material can be lowered. For example, as a solder material having a melting point of 180 ° C. or lower among Sn—Bi solder materials, Sn—Bi solder materials containing 35 wt.% Or more and 70 wt.% Or less of Bi can be given. Examples of the solder material having a melting point of 160 ° C. or lower include Sn—Bi based solder materials containing 50 wt% or more and 63 wt% or less of Bi. In particular, the solder member is preferably formed of an Sn-58Bi solder material containing 58 wt% (wt%) Bi. When 58 wt% Bi is contained, a solder material having the lowest melting point (eutectic point, 139 ° C.) among Sn—Bi solder materials can be obtained, and the loss of polarization can be further prevented. it can. The solder member may be formed of, for example, an Sn-57Bi-1Ag solder material in addition to the Sn-58Bi solder material. In this case, the strength of the solder material having a low melting point can be increased by containing Ag (silver).

  By connecting the electrodes 104a and 104b of the piezo element 104 to the element connection terminals 45 and 46 using such a solder member 105, the bonding reliability can be improved. That is, a silver paste can be used in place of the solder member 105, but the solder member 105 can improve the adhesive strength as compared with the silver paste. Therefore, even when the contact area between the solder member 105 and the element connection terminals 45 and 46 is small, the bonding reliability between the solder member 105 and the element connection terminals 45 and 46 can be improved. Further, when silver paste is used, silver filler constituting the silver paste may be scattered and become a contamination source in the hard disk drive 121. However, when the solder member 105 is used, such contamination is caused. Can be avoided.

  Next, the suspension substrate 1 will be described.

  As shown in FIG. 1, the suspension substrate 1 includes a head region (gimbal region) 2 on which the head slider 112 and the piezoelectric element 104 are mounted, and a tail region 3 to which an FPC substrate (external connection substrate) 131 is connected. ,have. The head region 2 is provided with a plurality of head terminals 41 connected to the head slider 112, and the tail region 3 is provided with a plurality of tail terminals (external connection substrate terminals) 42 connected to the FPC board 131. Yes. The head terminal 41 and the tail terminal 42 are respectively connected by a plurality of signal wirings 43 described later.

  As shown in FIGS. 1, 2, and 4, the suspension substrate 1 includes a metal support layer 20, an insulating layer 10 provided on the metal support layer 20, and a plurality of wirings provided on the insulating layer 10. And a wiring layer 40 having 43 and 44. That is, the wiring layer 40 is laminated on the metal support layer 20 via the insulating layer 10. A protective layer 50 that covers the wirings 43 and 44 is provided on the insulating layer 10. The head slider 112 described above is disposed on the protective layer 50 side (on the protective layer 50) of the suspension substrate 1, and the piezo element 104 is disposed on the metal support layer 20 side. In FIGS. 1 and 2, the protective layer 50 is omitted for the sake of clarity.

  As shown in FIGS. 2 and 4, the metal support layer 20 includes a metal support layer main body 21 and a tongue portion 22 that is disposed in the head region 2 and to which the head slider 112 is attached. The metal support layer main body 21 and the tongue portion 22 are connected by a central connecting portion 24 that extends along the longitudinal axis (X). The width of the central connecting portion 24 is reduced, whereby the central connecting portion 24 has flexibility, prevents the pivot movement of the head slider 112 from being inhibited, and prevents the piezoelectric element 104 from expanding and contracting. Is prevented.

  In the head region 2, an accommodation opening 25 for accommodating the piezo element 104 is provided in the metal support layer 20. The accommodation opening 25 is disposed on both sides of the central coupling portion 24. That is, the central connecting portion 24 is disposed between the pair of accommodation openings 25. In the present embodiment, the member constituting the metal support layer 20 is not formed on the outer side of the accommodation opening 25 (the side opposite to the side of the central coupling portion 24). However, a member constituting the metal support layer 20 may be formed outside the accommodation opening 25 as long as there is no hindrance to the expansion / contraction operation of the piezo element 104.

  The wiring layer 40 includes a plurality of wirings, that is, a signal wiring 43 including a pair of reading wirings and a pair of writing wirings, and a pair of element wirings 44 connected to the piezoelectric element 104. Among these, the signal wiring 43 connects the head terminal 41 and the tail terminal 42, and an electric signal is passed through the signal wiring 43, so that the head slider 112 receives data from the disk 123 (see FIG. 8). Write or read. The element wiring 44 extending from the tail terminal 42 is connected to the second element connection terminal 46, and applies a predetermined voltage to the second electrode 104 b of the piezo element 104.

  The wiring layer 40 includes a first element connection terminal 45 connected to the first electrode 104a of the piezo element 104 and a second element connection terminal 46 connected to the second electrode 104b of the piezo element 104. . Among these, the first element connection terminal 45 grounds the first connection pad 104 d of the first electrode 104 a of the piezo element 104. That is, the first element connection terminal 45 is for grounding the piezo element 104 and is electrically connected to the tongue portion 22 of the metal support layer 20 through the conductive connection portion 60 described later. Yes. As described above, the second element connection terminal 46 is for applying a predetermined voltage to the second connection pad 104e of the second electrode 104b of the piezo element 104, and the second element connection terminal 46 includes The element wiring 44 is connected.

  As shown in FIG. 4, the insulating layer 10 is provided with a first terminal opening 11 and a second terminal opening 12 that expose the element connection terminals 45 and 46 to the housing opening 25 side. A plating layer (not shown) formed by applying nickel (Ni) plating and gold (Au) plating in this order to the exposed portions of the element connection terminals 45 and 46 in the terminal openings 11 and 12 is provided. It has been. This prevents the element connection terminals 45 and 46 from corroding and reduces the connection resistance between the electrodes 104 a and 104 b of the piezoelectric element 104 and the element connection terminals 45 and 46. The head terminal 41 and the tail terminal 42 are similarly provided with plating layers.

  As shown in FIG. 4, the above-described solder member 105 that electrically connects the piezo element 104 and the element connection terminals 45 and 46 is accommodated in the first terminal opening 11 and the second terminal opening 12. As a method for accommodating the solder member 105 in the terminal openings 11 and 12, a method of applying a solder paste having solder grains 106 (see FIG. 9A) in the terminal openings 11 and 12 by a printing method is suitable. is there. The solder paste is a paste in which fine powdery solder particles 106 are formed by a flux. Such a solder paste can be used as the solder member 105. In this case, the electrodes 104 a and 104 b of the piezoelectric element 104 and the element connection terminals 45 and 46 of the wiring layer 40 are electrically connected by melting the solder particles 106.

  As shown in FIGS. 5 and 6, the first terminal opening 11 is formed in a rectangular shape in plan view, and the width w1 of the first terminal opening 11 is equal to the width w2 of the piezo element 104 to be mounted. It is 80% or more and 120% or less. In particular, the width w1 of the first terminal opening 11 is preferably 96% or more of the width w2 of the piezo element 104, and more preferably the same as the width w2 of the piezo element 104 as shown in FIG. Here, the term “same” is not limited to the meaning of exactly the same, but is used as a meaning including a manufacturing error that can be regarded as the same. Further, the plan view is a state viewed from the stacking direction in which the metal support layer 20, the insulating layer 10, and the wiring layer 40 are stacked. More specifically, FIG. 1, FIG. 2, FIG. 5, FIG. Means the indicated state. FIG. 5 shows the relationship between the first terminal opening 11 and the piezoelectric element 104 on the second element connection terminal 46 side as an example, but the first terminal opening on the first element connection terminal 45 side is shown. The relationship between the part 11 and the piezo element 104 can also be made similar (the same applies to FIGS. 10 and 12 described later). 5 shows an example in which the element wiring 44 is formed below the second element connection terminal 46. As shown in FIGS. 1 and 2, the element wiring 44 is connected to the second element connection terminal 46. It may be formed on the side of 46.

  Further, in the present embodiment, the first terminal opening 11 is entirely covered with the piezo element 104. More specifically, as shown in FIGS. 5 and 7, an end side 11 a (corresponding to an end surface defining the first terminal opening 11) on the outer side in the expansion / contraction direction of the piezoelectric element 104 of the first terminal opening 11 is When the piezo element 104 is mounted, the piezo element 104 is arranged at a position that overlaps the end side (or end face) 104h in the expansion / contraction direction of the piezo element 104 in plan view, in other words, at a position that coincides with the end side 104h in plan view. That is, the first terminal opening 11 has a shape that coincides with the connection pads 104d and 104e of the piezo element 104 to be mounted in plan view. Here, the term “match” is not limited to the exact term “match”, but is used to include a manufacturing error or the like that can be regarded as a match.

  As shown in FIGS. 5 and 6, the second terminal opening 12 extends from the end side 11 a of the first terminal opening 11 to the outside of the piezoelectric element 104 and communicates with the first terminal opening 11. That is, a single second terminal opening 12 is formed so as to protrude from the end 11 a of the first terminal opening 11 to the outside of the piezoelectric element 104, and the first terminal opening 11 and the second terminal opening 12 are formed. An integral or continuous opening is formed without being spaced apart from each other.

  The second terminal opening 12 is formed in a rectangular shape in plan view, and the width w3 of the second terminal opening 12 is smaller than the width w1 of the first terminal opening 11 and the piezoelectric element 104 has a width w3. It is smaller than the width w2. Then, end sides 11a on the outer side in the expansion / contraction direction of the piezo element 104 of the first terminal opening 11 are formed on both outer sides of the second terminal opening 12 in the width direction. In other words, the second terminal opening 12 is formed on the center side of the first terminal opening 11. Here, the end side 11a of the first terminal opening 11 serves to restrict the displacement of the piezo element 104 in the expansion / contraction direction when the solder member 105 is melted. By forming the end side 11a on both outer sides in the width direction with respect to the first terminal opening 12, it is possible to make the positional deviation restriction with respect to the piezo element 104 act evenly in the width direction of the piezo element 104, and solder When the member 105 is melted, the piezo element 104 can be prevented from being tilted (turned) or displaced in plan view.

  As described above, the first element connection terminal 45 is electrically connected to the tongue part 22 of the metal support layer 20 by the conductive connection part (via) 60 penetrating the insulating layer 10 and the first element connection terminal 45. Yes. The conductive connection portion 60 is preferably formed by applying nickel plating or copper plating to through holes (not shown) formed in the insulating layer 10 and the first element connection terminals 45. In this way, the first element connection terminal 45 is grounded.

  Next, materials constituting each layer of the suspension substrate 1 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 or more and 10 μm or less. As a result, the insulation performance between the metal support layer 20 and the wirings 43 and 44 can be ensured, and loss of the rigidity of the suspension substrate 1 as a whole can be prevented.

  The wirings 43 and 44 of the wiring layer 40 are configured as conductors for transmitting electrical signals, and the materials of the wirings 43 and 44 are particularly limited as long as they have 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 43 and 44 is 5 micrometers or more and 18 micrometers or less. As a result, it is possible to ensure the transmission characteristics of the wirings 43 and 44 and to prevent the flexibility of the suspension substrate 1 as a whole from being lost. The head terminal 41, the tail terminal 42, and the element connection terminals 45 and 46 have the same material and the same thickness as the wirings 43 and 44, and constitute the wiring layer 40.

  The material of the metal support layer 20 is not particularly limited as long as it has desired conductivity, elasticity, and strength. For example, stainless steel, 42 alloy, aluminum, beryllium copper, or other copper Alloys can be used, and among these, stainless steel is preferred. The thickness of the metal support layer 20 is preferably 15 μm or more and 20 μm or less. As a result, the conductivity, elasticity, and strength of the metal support layer 20 can be ensured.

  As a material of the protective layer 50, it is preferable to use a resin material, for example, polyimide. The material of the protective layer 50 can be a photosensitive material or a non-photosensitive material. The thickness of the protective layer 50 is preferably 3 μm or more and 10 μm or less on the wirings 43 and 44.

  Next, the hard disk drive 121 in the present embodiment will be described with reference to FIG. 8 includes a case 122, a disk 123 that is rotatably attached to the case 122, stores data, a spindle motor 124 that rotates the disk 123, and a desired flying height on the disk 123. The hard disk drive 121 illustrated in FIG. And a suspension 111 with a head including a head slider 112 that writes and reads data to and from the disk 123. Among them, the suspension with head 111 is attached to the case 122 so as to be movable, and the voice coil motor 125 for moving the head slider 112 of the suspension with head 111 along the disk 123 is attached to the case 122. Yes. The suspension with head 111 is attached to the voice coil motor 125 via an arm 126, and is connected to an FPC board 131 (see FIG. 1) connected to a control unit (not shown) that controls the hard disk drive 121. ing. In this way, an electrical signal is transmitted between the control unit and the head slider 112 via the suspension board 1 and the FPC board 131.

  Next, a method for manufacturing the suspension substrate 1 according to the present embodiment will be described. Here, as an example, the case where the suspension substrate 1 is manufactured by the subtractive method will be described, but it can also be manufactured by the additive method.

  First, a laminate (not shown) in which the metal support layer 20, the insulating layer 10, and the wiring layer 40 are laminated is prepared. Subsequently, the wiring layer 40 is etched into a desired shape, so that the head terminal 41, the tail terminal 42, the wirings 43 and 44, and the element connection terminals 45 and 46 are formed. Among these, the head terminal 41 and the element connection terminals 45 and 46 are formed in the head region 2. Next, the protective layer 50 covering the wirings 43 and 44 is formed on the insulating layer 10 in a desired shape. Subsequently, the insulating layer 10 is etched into a desired shape. At this time, the first terminal opening 11 and the second terminal opening 12 are formed in the insulating layer 10 in the head region 2. Thereafter, the metal support layer 20 is etched into a desired shape and subjected to external processing. In the head region 2, the tongue 22 and the accommodation opening 25 are formed in the metal support layer 20. In this way, the suspension substrate 1 according to the present embodiment is obtained.

  Next, a method for manufacturing the suspension 101 according to the present embodiment including a method for mounting the piezo element 104 will be described.

  First, the above-described suspension substrate 1 is attached to the base plate 102 (see FIG. 1) via the load beam 103 by welding. In this case, first, the load beam 103 is fixed to the base plate 102 by welding, then, a jig hole (not shown) provided in the load beam 103 and a jig hole 5 provided in the suspension substrate 1. Thus, alignment of the load beam 103 and the suspension substrate 1 is performed. Thereafter, the metal support layer 20 of the suspension substrate 1 is welded, and the load beam 103 and the suspension substrate 1 are joined and fixed to each other.

  Next, the piezo element 104 is mounted. A method for mounting the piezo element 104 will be described with reference to FIG.

  First, as shown in FIG. 9A, the solder member 105 is accommodated in the first terminal opening 11 and the second terminal opening 12. Specifically, a solder paste having solder grains 106 is applied in the terminal openings 11 and 12 by a printing method.

  Subsequently, as shown in FIG. 9B, the piezo element 104 is accommodated in the accommodation opening 25 of the metal support layer 20. At this time, the piezo element 104 is arranged at a predetermined position so that the connection pads 104 d and 104 e of the piezo element 104 are in contact with the applied solder member 105 and overlap in plan view.

  Next, as shown in FIG. 9C, the solder member 105 is heated. As a result, the solder particles 106 melt and reflow, and the solder particles 106 on the first element connection terminals 45 are transferred to the first connection pads 104 d of the first electrodes 104 a of the piezoelectric elements 104 and the first element connection terminals 45. Welded. In this way, the first connection pad 104 d of the piezo element 104 is soldered to the first element connection terminal 45. Similarly, the solder particles 106 on the second element connection terminal 46 are welded to the second connection pad 104 e of the second electrode 104 b of the piezoelectric element 104 and the second element connection terminal 46. In this way, the second connection pad 104 e of the piezo element 104 is soldered to the second element connection terminal 46.

  When the reflow is performed, the width of the first terminal opening 11 is not less than 80% and not more than 120% of the width of the piezo element 104, so that the piezo element 104 is prevented from being displaced in the width direction and the piezo element. The pair of electrodes 104a and 104b of the element 104 can be prevented from being short-circuited.

  That is, when the width of the first terminal opening 11 is 80% or more and less than 100% of the width of the piezo element 104, the piezo element 104 in which the solder melted during reflow has a width larger than the width of the first terminal opening 11 is used. The force to wet and spread the entire connection pads 104d and 104e acts on the piezo element 104 and the piezo element 104 moves. Here, as shown in FIG. 10, when the piezo element 104 moves in the left direction shown in FIG. 10, the movement of the piezo element 104 is such that the side surface 104 g on the side opposite to the movement direction of the piezo element 104 is the first terminal opening. It can stop when it reaches the edge of the part 11. According to such a theory, when the width of the first terminal opening 11 is not less than 80% and less than 100% of the width of the piezo element 104, the movement amount (position shift amount) of the piezo element 104 in the width direction is determined as the piezo element. It can be suppressed within 10% of the width of 104. In general, the amount of displacement in the width direction of the piezo element 104 is allowed within 10% of the width of the piezo element 104. For this reason, the piezo element 104 can be disposed within an allowable range, and the piezo element 104 can be avoided from being treated as a mounting failure.

  Here, FIG. 11 shows the result of measuring the positional deviation amount of the piezo element 104 mounted on the suspension substrate 1 according to the present embodiment. In FIG. 11, the piezo element 104 is soldered to the element connection terminals 45 and 46 of each suspension board 1, and the amount of displacement from a predetermined position (target value) in the width direction of the piezo element 104 is measured. In FIG. 11, the absolute values of the measured misregistration amounts are plotted as examples, and a total of 20 measurement data are shown.

  The width of the piezoelectric element 104 was 230 μm, and the width of the first terminal opening 11 was 220 μm. In this case, the width of the first terminal opening 11 is about 96% of the width of the piezo element 104.

  As a comparative example, the amount of displacement in the width direction of the piezo element 104 when the width of the first terminal opening 11 is 140 μm is also measured in the same manner as in the present embodiment, and a total of 20 measurement data are shown. Plotted in the graph shown in FIG. The width of the first terminal opening 11 in the comparative example is about 61% of the width of the piezo element 104.

  It can be said that the data shown in FIG. 11 includes variation and includes data in which the displacement amount of the piezo element 104 is larger than a theoretically conceivable value. This variation is due to, for some reason, that the side surface 104f or 104g of the piezo element 104 has moved beyond the edge of the first terminal opening 11 in the direction of increasing the positional deviation, the piezo element 104 is tilted, and the like. Can think. Further, since the positional deviation amount is measured using the jig hole 5 (see FIG. 1) of the suspension substrate 1, the positional deviation of the piezo element 104 is also determined by the position and shape accuracy of the jig hole 5. It is considered that the amount of data can vary.

  However, as shown in FIG. 11, in the comparative example, the average value of the positional deviation amount in the width direction of the piezo element 104 is about 24 μm. On the other hand, in this embodiment, the piezo element is The average amount of positional deviation in the width direction of the element 104 was about 9 μm. Thus, by making the width of the first terminal opening 11 close to the width of the piezo element 104, the amount of displacement in the width direction of the piezo element 104 to be mounted is reduced, and the position shift in the width direction of the piezo element 104 is reduced. It was confirmed that the amount could be suppressed.

  Further, as shown in FIG. 11, the variation range of the positional deviation amount of the piezo element 104 in this embodiment is smaller than the variation range of the positional deviation amount of the piezo element 104 in the comparative example. Recognize. In other words, in this embodiment, the maximum value of the displacement amount of the piezo element 104 obtained by 20 measurements is about 22 μm, and the displacement amount of the piezo element 104 can be suppressed to within 22 μm. is made of. In general, when the width of the piezo element 104 is 230 μm, the allowable maximum value of the displacement amount of the piezo element 104 is 23 μm, which is 10% of the width of the piezo element 104. Therefore, according to the results shown in FIG. The piezo element 104 can be disposed within an allowable range, and the piezo element 104 can be prevented from being treated as a mounting failure. That is, by making the width of the first terminal opening 11 close to the width of the piezo element 104, the position shift amount of the piezo element 104 is a general allowable value of the position shift amount of the piezo element 104. It is possible to suppress variation exceeding 10% of the width, and to reduce the probability of being treated as a mounting failure.

  When the width of the first terminal opening 11 is not less than 80% and less than 100% of the width of the piezo element 104, a fillet (see FIG. 13) made of molten solder is formed outside the piezo element 104 in the width direction. Can be prevented. Therefore, the pair of electrodes 104a and 104b exposed at the side surfaces 104f and 104g of the piezo element 104 can be prevented from being short-circuited by a solder fillet.

  On the other hand, when the width of the first terminal opening 11 exceeds 100% of the width of the piezoelectric element 104 and is within 120%, the width of the first terminal opening 11 can be made larger than the width of the piezoelectric element 104. As a result, the self-alignment effect by the melted solder works, the positional displacement of the piezoelectric element 104 in the width direction is prevented, and the piezoelectric element 104 can be arranged at a predetermined position. In this case, a solder fillet (see FIG. 13) can be formed on the outer side in the width direction of the piezo element 104. However, since the width of the first terminal opening 11 is within 120% of the width of the piezo element 104, The height of the fillet formed can be reduced. As a result, the pair of electrodes 104a and 104b exposed at the side surfaces 104f and 104g of the piezo element 104 can be prevented from being short-circuited by a solder fillet.

  Further, when the width of the first terminal opening 11 is the same as the width of the piezo element 104, a self-alignment effect due to the melted solder works, and the displacement of the piezo element 104 in the width direction is prevented. Can be arranged at a predetermined position. Further, it is possible to prevent a fillet (see FIG. 13) formed of molten solder from being formed on the outer side in the width direction of the piezo element 104, and it is possible to prevent the pair of electrodes 104a and 104b of the piezo element 104 from being short-circuited.

  Further, at the time of reflow, the pair of end sides 11a on the outer side in the expansion / contraction direction of the piezoelectric element 104 in the first terminal opening 11 overlap with the end side 104h in the expansion / contraction direction of the piezoelectric element 104 accommodated in the accommodation opening 25 in plan view. ing. As a result, a self-alignment effect by the melted solder member 105 works, and the end side 11a of the first terminal opening 11 regulates the displacement of the piezoelectric element 104 in the expansion / contraction direction, and the expansion / contraction direction of the piezoelectric element 104 Is suppressed.

  In this way, it is possible to obtain the suspension 101 in which the piezo element 104 is suppressed from being displaced in the width direction and the expansion / contraction direction, and the pair of electrodes 104a and 104b of the piezo element 104 can be prevented from being short-circuited.

  By the way, the second terminal opening 12 extends from the end 11 a of the first terminal opening 11 to the outside of the piezo element 104. Thus, the solder fillet 107 can be formed by melting the solder member 105 accommodated in the second terminal opening 12. The formed fillet 107 adheres to an end (more specifically, end face) 104h in the expansion / contraction direction of the piezo element 104, increases the contact area between the piezo element 104 and the solder member 105, and solders the piezo element 104. The bonding strength due to can be improved. The fillet 107 can also restrict the movement of the piezo element 104 in the expansion / contraction direction, and can prevent the piezo element 104 from being displaced in the expansion / contraction direction.

  Next, the head slider 112 is mounted on the suspension 101 obtained as described above, and the suspension with head 111 according to the present embodiment is obtained. In this case, for example, the molten solder material is supplied onto the head terminal 41 by a solder jet method. As a result, the solder material supplied onto the head terminal 41 is welded to the slider terminal of the head slider 112 and the head terminal 41 to form a slider solder member. The slider terminal of the head slider 112 is soldered to the head terminal 41. Is done. In this way, the head slider 112 is mounted on the suspension substrate 1.

  Further, the suspension with head 111 is attached to the arm 126 of the hard disk drive 121 and the FPC board 131 (see FIG. 1) is connected to the tail terminal 42 of the suspension board 1 to obtain the hard disk drive 121 shown in FIG. It is done.

  When writing and reading data in the hard disk drive 121 shown in FIG. 8, the disk 123 is rotated by the spindle motor 124, and the head slider 112 of the suspension with head 111 is moved along the disk 123 by the voice coil motor 125. At this time, the head slider 112 floats while maintaining a desired flying height on the disk 123 while performing a pivot motion together with the tongue 22 under the influence of the airflow generated by the rotation of the disk 123. In this state, data is exchanged between the head slider 112 and the disk 123. During this time, an electrical signal is transmitted between the head slider 112 and a control unit (not shown) connected to the FPC board 131 via the suspension board 1 and the FPC board 131. Such an electric signal is transmitted between the head terminal 41 (see FIG. 1) and the tail terminal 42 by each signal wiring 43 in the suspension board 1.

  When moving the head slider 112, the voice coil motor 125 roughly adjusts the position of the head slider 112, and the piezo element 104 finely adjusts the position of the head slider 112. That is, by applying a predetermined voltage to the second electrode 104b of the piezo element 104, one piezo element 104 contracts in the direction along the longitudinal axis (X) (the direction of arrow P in FIG. 2) and the other This piezo element 104 extends. In this case, a predetermined voltage is input to the piezoelectric element 104 via the element wiring 44, the second element connection terminal 46, and the solder member 105.

  When the piezo element 104 expands and contracts, the head slider 112 mounted on the head region 2 moves in the sway direction (the arrow Q direction in FIG. 2). In this case, since the piezo element 104 is arranged and mounted with high accuracy, the head slider 112 can be aligned with a desired track of the disk 123 with high accuracy.

  As described above, according to the present embodiment, the width of the second terminal opening 12 extending from the outer side edge 11 a of the piezoelectric element 104 of the first terminal opening 11 is larger than the width of the first terminal opening 11. It is small and smaller than the width of the piezo element 104. Since the end side 11a of the first terminal opening 11 overlaps the end side 104h in the expansion / contraction direction of the piezo element 104 in plan view, when the solder member 105 is melted, the end side 11a of the first terminal opening 11 is The displacement of the piezo element 104 in the expansion / contraction direction can be restricted. Further, the solder fillet 107 can be formed on the outer side of the piezoelectric element 104 in the expansion / contraction direction by the solder member 105 accommodated in the second terminal opening 12. This fillet 107 can also prevent displacement of the piezo element 104 in the expansion / contraction direction. For this reason, the position shift in the expansion-contraction direction of the piezo element 104 can be suppressed.

  Further, according to the present embodiment, the contact area between the piezoelectric element 104 and the solder member 105 can be increased by the solder fillet 107 described above. Accordingly, the pair of electrodes 104a and 104b of the piezo element 104 can be prevented from being short-circuited, and the bonding strength of the piezo element 104 by solder can be improved.

  Further, according to the present embodiment, the second terminal opening 12 is formed in a rectangular shape in plan view. As a result, the amount of the solder member 105 accommodated in the second terminal opening 12 can be secured, and the height of the formed solder fillet 107 can be secured. For this reason, the bonding strength of the piezo element 104 with solder can be further improved.

  Further, according to the present embodiment, the width of the first terminal opening 11 of the insulating layer 10 in which the solder member 105 is accommodated is 80% or more and 120% or less of the width of the piezo element 104 to be mounted. . As a result, the width of the first terminal opening 11 can be made closer to the width of the piezo element 104. For this reason, it is possible to suppress the displacement of the piezo element 104 in the width direction.

  Further, according to the present embodiment, the height of the fillet that can be formed by the solder melted on the outer side in the width direction of the piezo element 104 can be reduced. This prevents the pair of electrodes 104a and 104b exposed at the side surfaces 104f and 104g of the piezo element 104 from being short-circuited by the fillet.

  Further, when the width of the first terminal opening 11 is 96% or more of the width of the piezo element 104 to be mounted, the amount of displacement in the width direction of the piezo element 104 can be further suppressed. Further, when the width of the first terminal opening 11 is the same as the width of the piezo element 104 to be mounted, the position shift in the width direction of the piezo element 104 can be further prevented by the self-alignment effect by the molten solder. Can do. Further, it is possible to further prevent the fillet from being formed on the outer side in the width direction of the piezo element 104, and to more reliably prevent the pair of electrodes 104a and 104b of the piezo element 104 from being short-circuited.

  As described above, the embodiments of the present invention have been described in detail. However, the suspension substrate, the suspension, the suspension with a head, and the hard disk drive according to the present invention are not limited to the above-described embodiments, and the gist of the present invention. Various modifications can be made without departing from the scope.

  In the above-described embodiment, the example in which the single rectangular second terminal opening 12 is provided has been described. However, the number and shape of the second terminal openings 12 can be arbitrary.

  For example, as shown in FIG. 12A, a plurality of second terminal openings 12 may be provided. In the form shown in FIG. 12A, three second terminal openings 12 are formed so as to extend to the outside of the piezoelectric element 104 from the end side 11 a of the first terminal opening 11. The three second terminal openings 12 are separated from each other, and the end side 11 a of the first terminal opening 11 is also formed between the second terminal openings 12. In this case, it is possible to disperse the solder fillets 107 in the width direction and equalize them while reducing the amount of the solder member 105 used, and effectively suppress the displacement of the piezoelectric element 104 in the expansion / contraction direction. In addition, the piezoelectric element 104 can be prevented from tilting (turning) in plan view when the piezoelectric element 104 expands and contracts.

  Further, the second terminal opening 12 may be formed in a tapered shape toward the outer side in the expansion / contraction direction of the piezo element 104. For example, as shown in FIG. 12B, the second terminal opening 12 is formed like an isosceles triangle in plan view, and the vertex of the triangle (the outermost vertex in the expansion / contraction direction, the most in FIG. 12B) The lower point) can be arranged on an axis extending in the expansion / contraction direction through the center of the piezoelectric element 104 in the width direction. In this case, it is possible to prevent the molten solder from flowing around and adhering to the side surfaces 104f and 104g of the piezo element 104. Further, as shown in FIG. 12C, two second terminal openings 12 are provided, each second terminal opening 12 is formed like a right triangle in plan view, and the first terminal openings 11 are formed. The sides extending perpendicularly from the end side 11 a may be spaced apart from each other in the width direction of the piezo element 104 and arranged outside in the width direction. In this case, the solder fillet 107 can be dispersed and equalized in the width direction while reducing the amount of the solder member 105 used, and the displacement of the piezoelectric element 104 in the expansion / contraction direction can be effectively suppressed. In addition, when the piezo element 104 expands and contracts, the piezo element 104 can be prevented from tilting (turning) in plan view.

  In the above-described embodiment, the example in which the width of the first terminal opening 11 is 80% or more and 120% or less of the width of the piezoelectric element 104 has been described. However, the present invention is not limited to this, and the width of the first terminal opening 11 is not limited to this range. Even in this case, it is possible to suppress the positional deviation in the expansion / contraction direction of the piezo element 104 and to prevent the pair of electrodes 104a and 104b of the piezo element 104 from being short-circuited, thereby improving the bonding strength of the piezo element 104 by solder. it can.

DESCRIPTION OF SYMBOLS 1 Suspension board | substrate 10 Insulating layer 11 1st terminal opening part 11a End side 12 Second terminal opening part 20 Metal support layer 25 Housing opening part 40 Wiring layer 45 1st element connection terminal 46 2nd element connection terminal 101 Suspension 104 Piezo element 104a, 104b Electrode 104h End 105 Solder member 111 Suspension with head 112 Head slider 121 Hard disk drive

Claims (9)

A suspension substrate having a head slider and a pair of electrodes connectable using a solder member, and an extendable actuator element for displacing the head slider,
A metal support layer;
An insulating layer provided on the metal support layer;
A wiring layer provided on the insulating layer and having an element connection terminal connected to the electrode of the actuator element via the solder member;
The metal support layer is provided with an accommodation opening for accommodating the actuator element,
The insulating layer is provided with a first terminal opening and a second terminal opening in which the element connection terminal is exposed to the accommodation opening and the solder member is accommodated.
The end of the first terminal opening on the outside in the expansion / contraction direction of the actuator element is disposed at a position overlapping the end in the expansion / contraction direction of the actuator element in plan view when the actuator element is mounted,
The second terminal opening extends from the end side of the first terminal opening to the outside of the actuator element and communicates with the first terminal opening.
Width of the second terminal opening is smaller than the width of the first terminal opening, and, rather smaller than the width of the actuator device mounted,
A suspension substrate, wherein a plurality of the second terminal openings are provided .   The suspension substrate according to claim 1, wherein the second terminal opening is formed in a rectangular shape in plan view.   2. The suspension substrate according to claim 1, wherein the second terminal opening is formed in a tapered shape toward an outer side in an expansion / contraction direction of the actuator element in a plan view. The width of the first terminal opening, suspension substrate according to any one of claims 1 to 3, characterized in that not more than 120% 80% of the width of the actuator element to be mounted. The suspension substrate according to claim 4 , wherein the width of the first terminal opening is 96% or more of the width of the actuator element to be mounted. The suspension substrate according to claim 4 or 5 , wherein a width of the first terminal opening is the same as a width of the actuator element to be mounted. The suspension substrate according to any one of claims 1 to 6 ,
The actuator element mounted on the suspension substrate,
The suspension according to claim 1, wherein the electrode of the actuator element is connected to the element connection terminal via the solder member housed in the terminal opening. A suspension according to claim 7 ;
A suspension with a head, comprising: the head slider mounted on the suspension. A hard disk drive comprising the suspension with a head according to claim 8 .

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