JP5131605B2 - Suspension board - Google Patents

Description

  The present invention relates to a suspension substrate, and more particularly to a suspension substrate that can reduce differential impedance and improve flying stability.

  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 spring metal layer and a plurality (for example, 4 to 6) of wiring layers laminated on the spring metal layer via an insulating layer, and each wiring layer has an electric signal. The data is written to or read from the disk.

  In recent years, it has been required to increase the speed of transmission lines, increase the amount of information processing, and improve the processing speed. For this purpose, it is necessary to reduce the transmission loss in the high frequency region and improve the electrical characteristics of the substrate such as the low impedance of the differential wiring.

  Further, the magnetic disk for recording information has a higher density than the conventional one, and therefore, it is necessary to control the relative position between the disk and the magnetic head slider with higher accuracy. In order to control the position of the slider with high accuracy, it is required that deformation such as torsion is reduced with respect to the suspension substrate.

  In order to deal with these problems, a suspension substrate in which wirings are overlapped in the stacking direction has been proposed as a technique for reducing impedance (see, for example, Patent Document 1). Here, the wiring is laminated only on one side with respect to the central line extending in the longitudinal direction of the suspension substrate, and the wiring on the first insulating portion is covered on the other side with respect to the central line. The thickness or width of the two insulating parts is adjusted to reduce the distortion of the suspension substrate.

JP 2010-135053 A

  However, in this case, the thickness or width of the second insulating portions located on both sides of the center line is asymmetric. For this reason, there is a problem that uneven warping occurs due to heating or the like during manufacturing, the balance of rigidity of the suspension substrate is lost, and the floating stability of the suspension substrate with respect to the disk is impaired.

  The present invention has been made in consideration of such points, and an object of the present invention is to provide a suspension substrate that can reduce differential impedance and improve flying stability.

  The present invention provides a first insulating layer, a spring material layer provided on one surface of the first insulating layer, a first wiring layer provided on the other surface of the first insulating layer, A second insulating layer provided on a surface of the first insulating layer on the first wiring layer side and covering the first wiring layer; and a second wiring layer laminated on the first wiring layer via the second insulating layer And a protective layer that is provided on a surface of the second insulating layer on the second wiring layer side and covers the second wiring layer, wherein the first insulating layer, the second insulating layer, and the protective layer are There is provided a suspension substrate characterized by having a plane shape symmetrical with respect to a center line extending in the longitudinal direction of the suspension substrate.

  In the suspension substrate described above, the second wiring layer may be arranged on one side and not arranged on the other side with respect to the center line.

  In the suspension substrate described above, the thickness of the protective layer may be smaller than the thickness of the second insulating layer.

  According to the present invention, the second wiring layer is laminated on the first wiring layer via the second insulating layer. Thereby, the differential impedance between the first wiring layer and the second wiring layer can be reduced. The first insulating layer, the second insulating layer, and the protective layer have symmetrical plane shapes with respect to the center line extending in the longitudinal direction of the suspension substrate. As a result, it is possible to prevent the occurrence of a biased warp due to heating during manufacturing, to improve the balance of rigidity of the suspension substrate, and to stabilize the floating of the suspension substrate with respect to the disk. Therefore, the differential impedance can be reduced and the flying stability 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. 2A is an enlarged plan view showing an example of the first insulating layer and each wiring layer provided on the first insulating layer in the suspension substrate according to the embodiment of the present invention. FIG. 2B is an enlarged plan view showing an example of a second insulating layer and a second wiring layer provided on the second insulating layer. FIG. 2C is an enlarged plan view showing an example of the protective layer. FIG. 3 is a diagram showing an example of a cross-sectional configuration of the suspension substrate in the embodiment of the present invention. FIG. 4 is a plan view showing an example of a suspension in the embodiment of the present invention. FIG. 5 is a plan view showing an example of a suspension with a head according to an embodiment of the present invention. FIG. 6 is a perspective view showing an example of a hard disk drive according to the embodiment of the present invention. 7A to 7E are views showing a method for manufacturing a suspension substrate in the embodiment of the present invention.

  A suspension substrate according to an embodiment of the present invention will be described with reference to FIGS.

  First, the overall configuration of the suspension substrate 1 will be described with reference to FIG. A suspension board 1 shown in FIG. 1 includes a mounting area 2 for mounting a slider 52 (see FIG. 5), an external connection area 3 connected to an external connection board (not shown), and a mounting area 2 and an external connection area 3. And an intermediate region 4 disposed therebetween. As shown in FIGS. 1 and 2, the mounting area 2 is provided with a head terminal (wiring pad) 5 connected to the slider 52, and the external connection area 3 is connected to an external connection terminal. 6, and wiring layers 14, 15, and 16 described later are connected between the head terminal 5 and the external connection terminal 6.

Further, as shown in FIG. 1, the spring material layer 11 is provided with a jig hole 21 for joining with a load beam 42 described later. The jig hole 21 is formed in the shape of an elongated hole or an ellipse. As shown in FIG. 1, the overall length of the suspension board is L ₁ , and the center of the jig hole 21 to the tip of the suspension board 1 is used. distance when the _{L 2, L 2} is a 0.10L ₁ ~0.15L _1.

  Next, a cross-sectional configuration of the suspension substrate 1 will be described with reference to FIG. The suspension substrate 1 is provided on the first insulating layer 10 and one surface (lower surface) of the first insulating layer 10. The suspension material layer 11 having conductivity and the other surface of the first insulating layer 10 ( And a first wiring layer 14 provided on the upper surface. A second insulating layer 12 that covers the first wiring layer 14 is provided on the surface of the first insulating layer 10 on the first wiring layer 14 side, and the second wiring is connected to the first wiring layer 14 via the second insulating layer 12. Layer 15 is laminated.

  As shown in FIGS. 2A, 2B, and 3, the second wiring layer 15 includes a first conductor portion 15a arranged on the same plane as the first wiring layer 14 in the mounting region 2, and an intermediate region. 4 is laminated on the first wiring layer 14 via the second insulating layer 12 and connected to the first conductor portion 15a, and in the external connection region 3, on the same plane as the first wiring layer 14. And a third conductor portion (not shown) connected to the second conductor portion 15b.

  As shown in FIG. 2, the first wiring layer 14 and the second wiring layer 15 are arranged on one side (planar center line: X) extending in the longitudinal direction of the suspension substrate 1 (see FIG. 2A). ) And (b) on the right side). That is, the first wiring layer 14 and the second wiring layer 15 are not arranged on the other side (the left side in FIGS. 2A and 2B) with respect to the plane center line (X). Here, the plane center line (X) includes the major axis (major axis) of the jig hole 21 described above. 3 and 7 indicates a cross-sectional center line (Y) that intersects with the plane center line (X) and extends in the stacking direction of the suspension substrate 1.

  Further, as shown in FIG. 2A, the first wiring layer 14 is on the same plane and is opposite to the first wiring layer 14 with respect to the above-described plane center line (X) (FIG. 2 ( On the left side in a), two third wiring layers 16 and a ground wiring layer 30 are provided.

  The first wiring layer 14 and the second wiring layer 15 constitute a writing wiring (writer wiring). Further, the second conductor portion 15b of the second wiring layer 15 and the portion of the first wiring layer 14 corresponding to the second conductor portion 15b are as shown in FIGS. 2 (a), 2 (b), and FIG. The width is wider than that of the third wiring layer 16, and the impedance of the first wiring layer 14 and the second wiring layer 15 is reduced. The two third wiring layers 16 constitute a reading wiring (lead wiring).

  As shown in FIG. 3, a protective layer 22 covering the second conductor portion 15b of the second wiring layer 15 is provided on the surface of the second insulating layer 12 on the second wiring layer 15 side, and the second wiring The second conductor portion 15b of the layer 15 is prevented from being deteriorated. The thickness of the protective layer 22 is preferably smaller than the thickness of the second insulating layer 12. This can prevent the suspension substrate 1 from warping. Further, as shown in FIG. 2C, the protective layer 22 is preferably divided at the front end side of the suspension substrate 1 in order to prevent the suspension substrate 1 from warping.

  As shown in FIG. 2, the first insulating layer 10, the second insulating layer 12, and the protective layer 22 have a plane shape that is symmetrical with respect to the plane center line (X) of the suspension substrate 1. That is, in the portion extending from the jig hole 21 to the mounting region 2, the first insulating layer 10, the second insulating layer 12, and the protective layer 22 are arranged at positions that are line-symmetric with respect to the plane center line (X). And the width and thickness of each are symmetrical.

  As shown in FIG. 2B, the second insulating layer 12 is continuously formed without being divided on the front end side of the suspension substrate 1. In addition, the second insulating layer 12 is thicker than the protective layer 22 in order to adjust electrical characteristics such as impedance between the opposing first wiring layer 14 and the second conductor portion 15 b of the second wiring layer 15. Is getting bigger. For this reason, as described above, the warp and distortion of the suspension substrate 1 can be suppressed by making the planar shape of the second insulating layer 12 symmetrical with respect to the planar center line (X).

  As shown in FIG. 2B, a wiring conductive connection portion 20 that connects the first conductor portion 15 a and the second conductor portion 15 b of the second wiring layer 15 is provided in the second insulating layer 12. The wiring conductive connection portion 20 is formed integrally with the second conductor portion 15 b of the second wiring layer 15 in a wiring through hole (not shown) formed in the second insulating layer 12.

  As shown in FIG. 2A, a ground conductive connecting portion 31 that connects the ground wiring layer 30 and the spring material layer 11 is provided in the first insulating layer 10. The ground conductive connection portion 31 is formed by nickel plating or copper plating, and penetrates the first insulating layer 10, the ground wiring layer 30, and the second insulating layer 12. That is, the ground conductive connection portion 31 is formed in the first insulating layer through hole formed in the first insulating layer 10, the ground wiring layer through hole formed in the ground wiring layer 30, and the second insulating layer 12. In addition, the second insulating layer through-holes (both not shown) are formed by applying nickel plating or copper plating. Further, as shown in FIG. 2C, the protective layer 22 is provided with an exposure hole 33 that exposes the ground conductive connection portion 31 to the outside.

  2A to 2C, the wiring conductive connection portion 20 that connects the first conductor portion 15a and the second conductor portion 15b of the second wiring layer 15, the ground wiring layer 30, and the spring property. The ground conductive connection portions 31 that connect the material layer 11 are arranged symmetrically with respect to the plane center line (X) of the suspension substrate 1. However, the present invention is not limited to this, and the wiring conductive connection portion 20 and the ground conductive connection portion 31 may be arranged at arbitrary positions.

  Next, each component will be described in detail.

  The material of the first insulating layer 10 and the second insulating layer 12 is not particularly limited as long as it has a desired insulating property. For example, it is preferable to use polyimide (PI). Note that the material of each of the insulating layers 10 and 12 can be a photosensitive material or a non-photosensitive material. The thickness of the first insulating layer 10 is preferably 4 μm to 30 μm, more preferably 5 μm to 15 μm. As a result, it is possible to ensure insulation performance between the spring material layer 11 and the wiring layers 14, 15, 16, 30 and to prevent loss of the elasticity of the suspension substrate 1 as a whole. it can. Moreover, it is preferable that the thickness of the 2nd insulating layer 12 is 4 micrometers-20 micrometers. In particular, the thickness between the first wiring layer 14 and the second conductor portion 15b of the second wiring layer 15 in the intermediate region 4 is preferably 5 to 15 μm. As a result, the insulation performance between the first wiring layer 14 and the second wiring layer 15 can be secured, the differential impedance can be adjusted, and the differential impedance can be reduced.

  The material of each of the wiring layers 14, 15, 16, and 30 is not particularly limited as long as it has a desired conductivity, but it is preferable to use copper (Cu). In addition to copper, any material having electrical characteristics similar to pure copper can be used. Here, the thickness of each of the wiring layers 14, 15, 16, and 30 is preferably 1 μm to 18 μm, particularly preferably 5 μm to 12 μm, for example. As a result, the conductivity of each of the wiring layers 14, 15, 16, and 30 can be secured, and loss of the elasticity of the suspension substrate 1 as a whole can be prevented. Moreover, the width of each wiring layer 14, 15, 16, 30 is 5 μm to 1000 μm. In particular, the width of the second conductor portion 15b of the first wiring layer 14 and the second wiring layer 15 in the intermediate region 4 is 30. It is preferable that it is -300 micrometers. Thereby, the differential impedance can be adjusted, and the differential impedance can be reduced.

  The material of the spring material layer 11 is not particularly limited as long as it has desired conductivity, elasticity, and strength. For example, stainless steel, aluminum, beryllium copper, or other copper alloys are used. It is possible to use stainless steel, preferably stainless steel. Further, the thickness of the spring material layer 11 is preferably 10 μm to 30 μm, more preferably 15 μm to 25 μm. Thereby, the conductivity and elasticity of the spring material layer 11 can be ensured.

  As a material of the protective layer 22, it is preferable to use a resin material, for example, polyimide (PI). The material of the protective layer 22 can be a photosensitive material or a non-photosensitive material. The thickness of the protective layer 22 is preferably 3 μm to 20 μm, and particularly preferably smaller than the thickness of the first insulating layer 10 and the thickness of the second insulating layer 12.

  The head terminal 5 and the external connection terminal 6 are formed by sequentially applying nickel (Ni) and gold (Au) to the end portions of the wiring layers 14, 15, 16, and 30. Thus, the surface of the head terminal 5 and the external connection terminal 6 is prevented from deteriorating, and the contact resistance between the slider 52 and the slider pad (not shown) is reduced.

  Next, a suspension 41 using the suspension substrate 1 in the present embodiment will be described with reference to FIG. The suspension 41 shown in FIG. 4 is provided on the surface (lower surface) opposite to the suspension substrate 1 and the mounting area 2 of the suspension substrate 1 described above, and a slider 52 (see FIG. And a load beam 42 for holding (see FIG. 6).

  Next, a suspension 51 with a head using the suspension substrate 1 in the present embodiment will be described with reference to FIG. A suspension 51 with a head shown in FIG. 5 includes the above-described suspension 41 and a slider 52 mounted on the mounting region 2 of the suspension substrate 1.

  Next, a hard disk drive 61 using the suspension substrate 1 in this embodiment will be described with reference to FIG. A hard disk drive 61 shown in FIG. 6 is attached to a case 62, a disk 63 rotatably attached to the case 62 and storing data, a spindle motor 64 for rotating the disk 63, and a desired flying height on the disk 63. And a suspension 51 with a head including a slider 52 for writing and reading 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 slider 52 of the suspension with head 51 along the disk 63 is attached to the case 62. An arm 66 is connected between the suspension 51 with head and the voice coil motor 65.

  Next, the operation of the present embodiment having such a configuration, that is, a method for manufacturing the suspension substrate 1 will be described. Here, an example in which the first wiring layer 14 and the ground wiring layer 30 are formed by a subtractive method will be described. In FIG. 7, the first conductor portion 15 a and the third conductor portion of the second wiring layer 15 and the ground wiring layer 30 are omitted, but in the same manner as the step of forming the first wiring layer 14 shown below. Can be formed into a desired shape.

  First, as shown in FIG. 7A, a first insulating layer 10, a spring material layer 11 having conductivity provided on the lower surface of the first insulating layer 10, and an upper surface of the first insulating layer 10 are provided. A laminated body 25 having the provided wiring material layer 26 is prepared. In the laminate 25, the spring material layer 11 and the wiring material layer 26 may be formed by plating, or the first insulating layer 10, the spring material layer 11 and the wiring material layer 26 are bonded to each other. May be.

  Next, as shown in FIG. 7B, the first wiring layer 14 and the third wiring layer 16 are formed from the wiring material layer 26, and jig holes (see FIG. 2) are formed in the spring material layer 11. It is formed. In this case, first, a patterned resist (not shown) is formed on both surfaces of the laminate 25. Subsequently, the wiring material layer 26 is etched from the opening of the resist with a corrosive liquid such as a ferric chloride aqueous solution to form the first wiring layer 14 and the third wiring layer 16, and the spring material. A jig hole is formed in the layer 11. At this time, although not shown, a ground wiring layer through hole (not shown) for forming the ground conductive connection portion 31 is formed in the ground wiring layer 30. Thereafter, these resists are peeled off.

  Next, as shown in FIG. 7C, the second insulating layer 12 is laminated on the first wiring layer 14, and penetrates through the second insulating layer 12 to form the wiring conductive connection portion 20. A wiring through hole (not shown) is formed. In this case, first, the second insulating layer 12 is formed above the first insulating layer 10 so as to cover the wiring layers 14 and 16. Subsequently, a patterned resist (not shown) is formed on the surface of the second insulating layer 12, and a resist (not shown) is formed on the entire surface of the spring material layer 11. Next, the second insulating layer 12 is etched from the opening of the patterned resist with an etching solution such as an organic alkaline solution to form a wiring through hole. At this time, a second insulating layer through-hole for forming the ground conductive connection portion 31 is formed in the second insulating layer 12. Thereafter, these resists are peeled off.

  Next, as shown in FIG. 7D, the wiring conductive connection portion 20 is formed in the wiring through hole formed in the second insulating layer 12, and the second insulating layer 12 is laminated. A second conductor portion 15b of the two wiring layers 15 is formed. In this case, first, a sputter seed layer (not shown) including a metal thin film layer and a Cu sputtering layer is formed on the second insulating layer 12 by sputtering. Subsequently, a patterned resist (not shown) is formed on the sputter seed layer. The spring material layer 11 is formed with a resist (not shown) over the entire surface. Subsequently, the conductive connection part 20 for wiring is formed in the through hole for wiring and the second conductor portion 15b of the second wiring layer 15 is formed in the opening of the patterned resist by electrolytic copper plating. The Next, these resists are stripped, and then the exposed portion of the sputter seed layer is removed.

  Next, as shown in FIG. 7E, a protective layer 22 that covers the second conductor portion 15b of the second wiring layer 15 is formed on the second insulating layer 12, and a conductive layer for grounding is formed on the protective layer 22. An exposure hole 33 for exposing the connection portion 31 to the outside is formed. In this case, first, the protective layer 22 is formed over the entire region above the first insulating layer 10. Subsequently, a patterned resist (not shown) is formed on the protective layer 22, and a resist (not shown) is formed on the entire surface of the spring material layer 11. Next, the protective layer 22 is etched with an etching solution from the opening of the patterned resist, and the protective layer 22 is trimmed into a desired shape, so that the exposed holes 33 are formed. Thereafter, these resists are peeled off.

  Next, the first insulating layer 10 is etched in the same manner as the second insulating layer 12 to be processed into a desired shape, and a first conductive layer 31 for grounding is formed in the first insulating layer 10. An insulating layer through-hole is formed.

  Next, Ni plating and Au plating are sequentially formed on the exposed portions of the respective wiring layers 14, 15, 16, 30, the head terminals 5 are formed in the mounting region 2, and in the external connection region 5, External connection terminals 6 are formed.

  Next, the ground conductive connection portion 31 is formed in the first insulating layer through hole, the ground wiring layer through hole, and the second insulating layer through hole by nickel plating or copper plating.

  Thereafter, the spring material layer 11 is processed into a desired shape by etching.

  The load beam 42 is attached to the lower surface of the suspension substrate 1 obtained in this way, and the suspension 41 shown in FIG. 4 is obtained. A slider 52 is mounted on the mounting area 2 of the suspension 41 to obtain a suspension 51 with a head shown in FIG. Furthermore, the suspension 51 with the head is attached to the case 62 of the hard disk drive 61, and the hard disk drive 61 shown in FIG. 6 is obtained.

  When reading and writing data in the hard disk drive 61 shown in FIG. 6, the 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 moved. Keep close to the desired flying height. As a result, data is transferred between the slider 52 and the disk 63. During this time, electrical signals are transmitted by the wiring layers 14, 15, 16 connected between the head terminals 5 in the mounting area 2 of the suspension substrate 1 and the external connection terminals 6 in the external connection area 3.

  Thus, according to the present embodiment, the second wiring layer 15 is laminated on the first wiring layer 14 via the second insulating layer 12. Thereby, the differential impedance between the first wiring layer and the second wiring layer can be reduced. Further, the first insulating layer 10, the second insulating layer 12, and the protective layer 22 have symmetrical plane shapes with respect to the plane center line (X) extending in the longitudinal direction of the suspension substrate 1. As a result, it is possible to prevent the occurrence of biased warping due to heating during manufacturing, to improve the balance of rigidity of the suspension substrate 1, and to stabilize the floating of the suspension substrate 1 with respect to the disk 63. Can do. As a result, the differential impedance can be reduced and the flying stability can be improved.

  Further, according to the present embodiment, the first wiring layer 14 and the second wiring layer 15 as described above constitute the writing wiring. Thus, the differential impedance of the write wiring can be reduced, the data writing speed to the disk 63 can be improved, and the power consumption can be suppressed. Further, the transmission loss of the first wiring layer 14 and the second wiring layer 15 is reduced, so that the stability of data writing to the disk 63 can be improved. Note that the first wiring layer 14 and the second wiring layer 15 may constitute a reading wiring instead of a writing wiring. Also in this case, since the above-mentioned effect can be obtained, the reliability of reading data from the disk 63 can be improved. Furthermore, the first wiring layer 14 and the second wiring layer 15 may constitute an electronic element wiring that requires a signal from a differential wiring. Even in this case, since the above-described effect can be obtained, the reliability of the operation of the electronic element can be improved.

  Furthermore, according to the present embodiment, the suspension 41, the suspension with head 51, and the hard disk drive 61 having the above-described effects can be obtained.

  In the present embodiment, the first wiring layer 14, the first conductor portion 15a and the third conductor portion of the second wiring layer 15, the third wiring layer 16, and the ground wiring layer 30 are formed by a subtractive method. An example to be described. However, the present invention is not limited to this, and these wiring layers 14, 15, 16, and 30 may be formed by an additive method.

  In the present embodiment, as shown in FIG. 3, an example is described in which the wiring layers 14, 15, 16, and 30 are disposed above and the spring material layer 11 is disposed below the insulating layer 10. However, the wiring layers 14, 15, 16, and 30 may be disposed below and the spring material layer 11 may be disposed above.

  As mentioned above, although the embodiment of the present invention has been described in detail, the suspension substrate according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Is possible.

DESCRIPTION OF SYMBOLS 1 Suspension board | substrate 2 Mounting area | region 3 External connection area | region 4 Intermediate | middle area | region 5 Head terminal 6 External connection terminal 10 1st insulating layer 11 Spring property layer 12 2nd insulating layer 14 1st wiring layer 15 2nd wiring layer 15a 1st conductor Portion 15b Second conductor portion 16 Third wiring layer 20 Wiring conductive connection 21 Jig hole 22 Protective layer 25 Laminate 26 Wiring material layer 30 Ground wiring layer 31 Ground conductive connection 33 Exposed hole 41 Suspension 42 Load beam 51 Suspension with head 52 Slider 61 Hard disk drive 62 Case 63 Disk 64 Spindle motor 65 Voice coil motor 66 Arm

Claims (2)

In the suspension board on which the slider is mounted,
A first insulating layer;
A spring material layer provided on one surface of the first insulating layer;
A first wiring layer provided on the other surface of the first insulating layer;
A second insulating layer provided on a surface of the first insulating layer on the first wiring layer side and covering the first wiring layer;
A second wiring layer laminated on the first wiring layer via the second insulating layer;
A protective layer that is provided on a surface of the second insulating layer on the second wiring layer side and covers the second wiring layer;
The first insulating layer, the second insulating layer, and the protective layer are disposed on both sides of a center line extending in the longitudinal direction of the suspension substrate, and each have a plane shape that is symmetric with respect to the center line.
The second wiring layer is disposed on one side with respect to the center line, not disposed on the other side ,
The suspension substrate , wherein the protective layer is connected to the slider and separated from a head terminal connected to the first wiring layer and the second wiring layer .   The suspension substrate according to claim 1, wherein a thickness of the protective layer is smaller than a thickness of the second insulating layer.

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