Disk device

Abstract

Embodiments provide a disk device capable of suppressing inclination of an electronic component. A disk device according to an embodiment includes a magnetic disk, a magnetic head, an FPC, and an electronic component. The FPC has an insulating layer, a first conductive layer provided on a first surface of the insulating layer, and a second conductive layer provided on a second surface of the insulating layer. The electronic component is mounted on the FPC. The first conductive layer has a plurality of pads. The electronic component has a plurality of terminals connected to the plurality of pads via solder. The second conductive layer has a plurality of wirings. The plurality of wirings include a first wiring having a first portion separated from the plurality of pads and a second portion that overlaps one of the plurality of pads and is thicker than the first portion, and at least one of a pair of second wirings that overlaps one of the plurality of pads.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority based on Japanese Patent Application No. 2023 - 217898 (filing date: December 25, 2023). This application incorporates all the contents of the base application by reference thereto. Technical field

[0003] This embodiment generally relates to a disk device. Background art

[0004] A disk device such as a hard disk drive has various components such as a magnetic head, a flexible printed circuit board, and electronic components. The magnetic head is electrically connected to the flexible printed circuit board and reads and writes information with respect to the magnetic disk. The electronic components are mounted on the pads of the flexible printed circuit board by solder.

[0005] The flexible printed circuit board has a plurality of insulating layers and a plurality of conductive layers. In the flexible printed circuit board, the portion where the pad does not overlap with other conductive layers is thinner than the portion where the pad overlaps with other conductive layers. Therefore, the pad that does not overlap with other conductive layers is farther from the electronic components than the pad that overlaps with other conductive layers.

[0006] During reflow soldering, the solder between the pads and the electronic components that are separated from each other by a greater distance stretches the electronic components toward the flexible printed circuit board with a stronger surface tension than the solder between the pads and the electronic components that are close to each other. Due to this imbalance in surface tension, the electronic components may tilt. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a disk device capable of suppressing tilting of electronic components.

[0008] The disk device according to the embodiment includes a magnetic disk, a magnetic head, a flexible printed circuit board, and an electronic component. The magnetic head is configured to read and write information relative to the magnetic disk. The flexible printed circuit board is electrically connected to the magnetic head and includes an insulating layer, a first conductive layer provided on a first surface of the insulating layer, and a second conductive layer provided on a second surface of the insulating layer located on the opposite side of the first surface. The electronic component is mounted on the flexible printed circuit board. The first conductive layer includes a plurality of pads. The electronic component includes a plurality of terminals connected to the plurality of pads via solder. The second conductive layer includes a plurality of wirings. The multiple wirings include a first wiring or multiple first wirings and at least one of a pair of second wirings or multiple pairs of second wirings, the first wiring or the multiple first wirings respectively having a first portion separated from the multiple pads along the second surface and a second portion overlapping with one of the multiple pads across the insulating layer, separated from the one pad by the insulating layer, and thicker than the first portion, and the pair of second wirings or each pair of the multiple pairs of second wirings overlaps with one of the multiple pads across the insulating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is an exemplary perspective view showing an exploded view of the HDD according to the first embodiment.

[0010] Figure 2 It is an exemplary plan view schematically showing the FPC according to the first embodiment.

[0011] Figure 3 This is an exemplary plan view showing a mounting portion of the FPC according to the first embodiment.

[0012] Figure 4 This is an illustrative plan view showing a part of the mounting portion according to the first embodiment.

[0013] Figure 5 The FPC and preamplifier of the first embodiment are connected along Figure 4 An exemplary cross-sectional view is represented by line F5-F5.

[0014] Figure 6 It is an exemplary plan view showing a mounting portion of an FPC according to the second embodiment.

[0015] Figure 7 It is an exemplary plan view showing a mounting portion of an FPC according to a third embodiment. DETAILED DESCRIPTION

[0016] (First embodiment)

[0017] Next, regarding the first embodiment, refer to Figures 1 to 5This will be described. In addition, in this specification, the components related to the embodiments and the descriptions of these components may be described by multiple expressions. The components and their descriptions are examples and are not limited by the expressions in this specification. The components can also be identified by names different from those of the components in this specification. In addition, the components can also be described by expressions different from those in this specification.

[0018] In the following description, "inhibit" is defined, for example, as preventing the occurrence of a phenomenon, action, or influence, or reducing the degree of a phenomenon, action, or influence. In addition, in the following description, "restrict" is defined, for example, as preventing movement or rotation, or allowing movement or rotation within a specified range and preventing movement or rotation beyond the specified range.

[0019] Figure 1 FIG. 7 is an exemplary perspective view showing the hard disk drive (HDD) 10 according to the first embodiment disassembled. The HDD 10 is an example of a disk device and can also be referred to as an electronic device, a storage device, an external storage device, or a disk unit. In addition, the disk device is not limited to the HDD 10.

[0020] As Figure 1 shown, the HDD 10 includes a housing 11, a plurality of disks 12, a spindle motor 13, a head stack assembly (HSA) 14, a voice coil motor (VCM) 15, a ramp loading mechanism 16, and a printed circuit board (PCB) 17. The disks 12 can also be referred to as disks, media, or platters.

[0021] The housing 11 includes a base 21, an inner cover 22, and an outer cover 23. In addition, the housing 11 is not limited to this example. The base 21 is formed in a substantially rectangular parallelepiped box shape that is open in one direction. The base 21 houses the plurality of disks 12, the spindle motor 13, the HSA 14, the VCM 15, and the ramp loading mechanism 16.

[0022] The base 21 has a bottom wall 25 and side walls 26. The bottom wall 25 is formed in a substantially rectangular (quadrilateral) plate shape. The side walls 26 project from the edge of the bottom wall 25 and are formed in a substantially rectangular frame shape. The inner cover 22 is mounted to the end of the side wall 26, for example, by screws, to block the base 21. The outer cover 23 covers the inner cover 22 and is mounted to the end of the side wall 26, for example, by welding.

[0023] An air vent 27 is provided in the inner cover 22. And an air vent 28 is provided in the outer cover 23. After installing components inside the base 21 and mounting the inner cover 22 and the outer cover 23 to the base 21, the air inside the housing 11 is discharged from the air vents 27 and 28. And a gas different from air is filled inside the housing 11.

[0024] The gas filled inside the housing 11 is, for example, a low-density gas with a density lower than that of air, or an inert gas with low reactivity, etc. For example, helium gas is filled inside the housing 11. In addition, other fluids can also be filled inside the housing 11.

[0025] The vent hole 28 of the outer cover 23 is blocked by the sealing portion 29. The sealing portion 29 hermetically seals the vent hole 28 and restricts the leakage of the fluid filled inside the housing 11 from the vent hole 28 to the outside of the housing 11.

[0026] The plurality of magnetic disks 12 are formed in a disk shape arranged substantially parallel to the bottom wall 25. The plurality of magnetic disks 12 are arranged at intervals. The spindle motor 13 supports the plurality of magnetic disks 12. The plurality of magnetic disks 12 are held by the hub of the spindle motor 13, for example, by a clamping spring. The spindle motor 13 rotates the plurality of magnetic disks 12.

[0027] A support shaft 31 separated from the magnetic disk 12 is provided on the housing 11. The support shaft 31 extends from the bottom wall 25 of the housing 11, for example. The HSA 14 is rotatably supported by the support shaft 31.

[0028] The HSA 14 has a carriage 35, a plurality of head gimbal assemblies (HGAs) 36, and a flexible printed circuit board (FPC) 37. The carriage 35 has an actuator module 41 and a plurality of arms 42.

[0029] The actuator module 41 is supported by the support shaft 31 via a bearing so as to be rotatable about the support shaft 31, for example. The plurality of arms 42 project substantially parallel from the actuator module 41.

[0030] The plurality of arms 42 are arranged at intervals. Each of the plurality of arms 42 can enter the gap between two adjacent magnetic disks 12 among the plurality of magnetic disks 12.

[0031] The VCM 15 has a voice coil mounted on the carriage 35, a pair of yokes, and a magnet provided on the yokes. The VCM 15 rotates the carriage 35 about the support shaft 31.

[0032] Each of the plurality of HGAs 36 has a base plate 45, a load beam 46, a flexible portion 47, and a magnetic head 48. The base plate 45 is mounted on the front end of the arm 42. The load beam 46 is formed thinner than the base plate 45 and extends from the base plate 45.

[0033] The flexible portion 47 is formed in an elongated strip shape. In addition, the shape of the flexible portion 47 is not limited to this example. The flexible portion 47 is a type of FPC, which has a metal plate (lining layer) such as stainless steel, an insulating layer (base layer) formed on the metal plate, a conductive layer constituting a plurality of wirings (wiring patterns) formed on the insulating layer, and an insulating layer (cover layer) covering the conductive layer.

[0034] At one end of the flexible portion 47, a gimbal portion (elastic support portion) that is disposed on the bearing beam 46 and capable of displacement is provided. The head 48 is mounted on the gimbal portion of the flexible portion 47. The head 48 records and reproduces information with respect to the recording layer of the magnetic disk 12. In other words, the head 48 reads and writes information with respect to the magnetic disk 12.

[0035] The VCM 15 rotates the carriage 35 to position the head 48 at a desired position on the magnetic disk 12. When the head 48 moves to the outermost circumference of the magnetic disk 12, the ramp loading mechanism 16 holds the head 48 at an unloading position separated from the magnetic disk 12.

[0036] The FPC 37 is connected to the other end of the flexible portion 47. For example, the FPC 37 connects a plurality of flexible portions 47. Thus, the FPC 37 is electrically connected to a plurality of heads 48 via the wirings of the plurality of flexible portions 47.

[0037] The PCB 17 is a rigid substrate such as a glass epoxy substrate, and is a multilayer substrate or a build-up substrate. The PCB 17 is disposed outside the housing 11 and is mounted on the bottom wall 25 of the base 21. The PCB 17 is mounted on the bottom wall 25 by, for example, a plurality of screws.

[0038] The HDD 10 further includes, for example, an interface (I / F) connector 51, a controller 52, and a relay connector 53. The I / F connector 51, the controller 52, and the relay connector 53 are mounted on the PCB 17. In addition, other components may be mounted on the PCB 17.

[0039] The I / F connector 51 is a connector that complies with an interface standard such as Serial ATA (SATA) and is connected to the I / F connector of the host computer. The controller 52 is, for example, a system-on-chip (SoC) and includes a read / write channel (RWC), a hard disk controller (HDC), and a processor.

[0040] The PCB 17 is electrically connected to various components disposed inside the housing 11 via the relay connector 53. For example, the PCB 17 is electrically connected to the spindle motor 13, the VCM 15, the FPC 37, and the head 48.

[0041] Figure 2 is a schematic illustrative plan view of the FPC 37 of the first embodiment. As Figure 2 shown, the FPC 37 is formed in a substantially L-shaped strip in a natural state where it is detached from other components and no external force is applied. In addition, the shape of the FPC 37 is not limited to this example. The FPC 37 has a first connection portion 61, a second connection portion 62, and an intermediate portion 63.

[0042] The first connection part 61 is provided, for example, at one end of the FPC 37 in the extending direction of the FPC 37. The first connection part 61 is mounted to the actuator module 41 by screws, for example. The first connection part 61 is connected to a plurality of flexible parts 47.

[0043] The second connection part 62 is provided, for example, at the other end of the FPC 37 in the extending direction of the FPC 37. The second connection part 62 is mounted to the bottom wall 25 by screws, for example. The second connection part 62 is electrically connected to the relay connector 53 on the PCB 17, for example.

[0044] The intermediate part 63 is provided between the first connection part 61 and the second connection part 62. The intermediate part 63 extends in a strip shape and flexes between the first connection part 61 and the second connection part 62 in response to the rotation of the actuator module 41.

[0045] As shown in the respective drawings, in the present specification, for convenience, the X-axis, Y-axis, and Z-axis are defined. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis is provided along the width of the intermediate part 63 in the natural state. The Y-axis is provided along the length of the intermediate part 63 in the natural state. The Z-axis is provided along the thickness of the FPC 37 in the natural state.

[0046] Moreover, in the present specification, the X-direction, Y-direction, and Z-direction are defined. The X-direction is the direction along the X-axis, including the +X direction indicated by the arrow of the X-axis and the -X direction opposite to the arrow of the X-axis. The Y-direction is the direction along the Y-axis, including the +Y direction indicated by the arrow of the Y-axis and the -Y direction opposite to the arrow of the Y-axis. The Z-direction is the direction along the Z-axis, including the +Z direction indicated by the arrow of the Z-axis and the -Z direction opposite to the arrow of the Z-axis.

[0047] The first connection part 61 is connected to the end of the intermediate part 63 in the +Y direction and extends from this end in the +Y direction. The second connection part 62 is connected to the end of the intermediate part 63 in the -Y direction and extends from this end in the +X direction. In addition, the first connection part 61 and the second connection part 62 are not limited to this example.

[0048] The HDD 10 further includes a plurality of preamplifiers 65, relay connectors 66, and a plurality of reinforcing plates 67. The preamplifier 65 is an example of an electronic component and can also be referred to as a head IC. The preamplifier 65 is mounted to the first connection part 61 of the FPC 37.

[0049] The preamplifier 65 is electrically connected to the head 48 via the FPC 37 and the flexible portion 47. For example, the preamplifier 65 amplifies the write signal output from the controller 52 and outputs it to the head 48. The write signal is an electrical signal corresponding to the information written by the head 48 to the magnetic disk 12. Also, the preamplifier 65 receives the read signal from the head 48, amplifies it, and outputs it to the controller 52. The read signal is an electrical signal corresponding to the information read by the head 48 from the magnetic disk 12. The preamplifier 65 can input and output various other electrical signals.

[0050] The relay connector 66 is mounted on the second connection portion 62 of the FPC 37. The relay connector 66 is electrically connected to the relay connector 53 of the PCB 17 via, for example, a relay substrate provided on the bottom wall 25.

[0051] The reinforcing plate 67 is made of, for example, a metal such as aluminum or a synthetic resin and is formed in a plate shape. In addition, the reinforcing plate 67 is not limited to this example. A plurality of reinforcing plates 67 are mounted on the first connection portion 61 and the second connection portion 62.

[0052] The reinforcing plate 67 has higher rigidity than the FPC 37. Therefore, the reinforcing plate 67 increases the rigidity of the first connection portion 61 and the second connection portion 62. At least a part of the intermediate portion 63 is not mounted on the reinforcing plate 67 and can be flexed.

[0053] Figure 3 It is an exemplary plan view showing the mounting portion MP of the FPC 37 according to the first embodiment. The FPC 37 has a plurality of mounting portions MP. The mounting portion MP is the part of the first connection portion 61 of the FPC 37 where the preamplifier 65 is mounted. In other words, the mounting portion MP is the part of the first connection portion 61 that overlaps (is covered by) the preamplifier 65 in the Z direction. Figure 3 The outer shape of the preamplifier 65 projected in the Z direction is indicated by a two-dot chain line.

[0054] Figure 4 It is an exemplary plan view showing a part of the mounting portion MP according to the first embodiment. Figure 5 It is an exemplary cross-sectional view showing the FPC 37 and the preamplifier 65 according to the first embodiment along the Figure 4 line F5 - F5. As Figure 5 shown, the FPC 37 has a base layer 70, a first conductive layer 71, a second conductive layer 72, a plurality of vias 73, a first cover layer 74, a second cover layer 75, and a plurality of adhesive layers 76. In addition, the FPC 37 may have three or more conductive layers. The base layer 70 is an example of an insulating layer. In addition, Figure 3 and Figure 4 For the sake of understanding, the first cover layer 74 is omitted.

[0055] The base layer 70, the first cover layer 74, and the second cover layer 75 are made of an insulating synthetic resin such as polyimide (PI). In addition, the materials of the base layer 70, the first cover layer 74, and the second cover layer 75 are not limited to this example.

[0056] The base layer 70 has a first surface 70a and a second surface 70b. The first surface 70a faces the substantially +Z direction. The second surface 70b is located on the opposite side of the first surface 70a and faces the substantially -Z direction. The second surface 70b faces the actuator module 41.

[0057] The first conductive layer 71, the second conductive layer 72, and the vias 73 are made of a conductive metal such as copper, for example. In addition, the materials of the first conductive layer 71, the second conductive layer 72, and the vias 73 are not limited to this example. The first conductive layer 71 and the second conductive layer 72 form wiring patterns.

[0058] The first conductive layer 71 is provided on the first surface 70a of the base layer 70. As Figure 4 shown, the first conductive layer 71 has a plurality of pads 81 and a plurality of wirings 82. The pads 81 can also be referred to as pad portions, electrodes, or terminals, for example.

[0059] The pads 81 are electrodes provided on the mounting portion MP. The plurality of pads 81 are each formed in a substantially circular shape, for example. In addition, the shape of the pads 81 is not limited to this example. The first conductive layer 71 also has a plurality of other pads provided outside the mounting portion MP. The plurality of wirings 82 each connect at least two of the plurality of pads 81 provided on the mounting portion MP, the plurality of other pads provided outside the mounting portion MP, and the plurality of vias 73.

[0060] As Figure 5 shown, the second conductive layer 72 is provided on the second surface 70b of the base layer 70. As Figure 4 shown, the second conductive layer 72 has a plurality of wirings 85 and a ground plane 86. The plurality of wirings 85 each connect at least two of the plurality of vias 73.

[0061] As Figure 5 shown, the vias 73 penetrate the base layer 70 and connect the first conductive layer 71 and the second conductive layer 72. For example, the plurality of vias 73 each connect one of the plurality of wirings 82 of the first conductive layer 71 and one of the plurality of wirings 85 of the second conductive layer 72.

[0062] As Figure 3 shown, the wiring 85 of the second conductive layer 72 has a plurality of first wirings 91 and a plurality of pairs of second wirings 92. In addition, the numbers of the first wirings 91 and the second wirings 92 are not limited to this example. The wiring 85 includes at least one of the first wiring 91 and a pair of second wirings 92.

[0063] As shown Figure 4 in FIG. 1, each of a plurality of first wirings 91 has at least one thin portion 95 and one thick portion 96. The thin portion 95 is an example of a first portion. The thick portion 96 is an example of a second portion. The first wiring 91 may have a plurality of thin portions 95 and a plurality of thick portions 96.

[0064] The thin portion 95 is a relatively thin portion in the first wiring 91. For example, the width W1 of the thin portion 95 is shorter than the diameter of the pad 81, for example, about 29 μm. In addition, the width W1 of the thin portion 95 is not limited to this example. The width is a dimension in a direction orthogonal to the direction in which each portion of the wirings 82 and 85 extends.

[0065] In the present embodiment, the thin portion 95 is separated from the pad 81 along the second surface 70b. In other words, the thin portion 95 does not overlap the pad 81 with the base layer 70 therebetween. In addition, the thin portion 95 may overlap other pads provided outside the mounting portion MP.

[0066] The thick portion 96 is a relatively thick portion in the first wiring 91. That is, the thick portion 96 is thicker than the thin portion 95. For example, the width W2 of the thick portion 96 is the same as or wider than the diameter (width) of the pad 81. In addition, the width W2 of the thick portion 96 is not limited to this example.

[0067] The thick portion 96 of each of the plurality of first wirings 91 overlaps at least one of the plurality of pads 81 with the base layer 70 therebetween. In other words, the thick portion 96 covers at least one of the plurality of pads 81 in the Z direction through the base layer 70.

[0068] The plurality of first wirings 91 include first wirings 91A, 91B, and 91C. In addition, the plurality of first wirings 91 may include other first wirings 91 different from the first wirings 91A, 91B, and 91C.

[0069] The first wiring 91A has two thin portions 95 and one thick portion 96. One thin portion 95 is an example of a first portion, and the other thin portion 95 is an example of a third portion. In the first wiring 91A, the thick portion 96 overlaps two adjacent pads 81 of the plurality of pads 81 with the base layer 70 therebetween. The thick portion 96 is separated from the two pads 81 by the base layer 70. In other words, the thick portion 96 and the pad 81 are not connected to each other through the via hole 73. In addition, the thick portion 96 and the pad 81 may be electrically connected to each other via the thin portion 95 and the via hole 73, for example.

[0070] In the first wiring 91A, two details 95 are separated from each other in the substantially Y direction. A thick portion 96 is located between the two details 95 and is connected to the two details 95. The thick portion 96 extends in the substantially Y direction between the two details 95. Two pads 81 overlapping the thick portion 96 are arranged at intervals in the substantially Y direction.

[0071] The first wiring 91B has one detail 95 and one thick portion 96. In the first wiring 91B, the thick portion 96 overlaps two adjacent pads 81A and 81B among the plurality of pads 81 with the base layer 70 interposed therebetween.

[0072] As Figure 5 shown, in the first wiring 91B, the thick portion 96 is separated from the pad 81A by the base layer 70. On the other hand, the via hole 73 connects the pad 81B and the thick portion 96. That is, the pad 81B is a pad on via.

[0073] As Figure 4 shown, in the first wiring 91B, the thick portion 96 extends from the end of the detail 95 in the substantially -Y direction. The pads 81A and 81B are arranged at intervals in the Y direction. The pad 81B is farther from the detail 95 than the pad 81A and is located at the end of the first wiring 91B.

[0074] The first wiring 91C has two details 95 and one thick portion 96. In the first wiring 91C, the thick portion 96 overlaps four adjacent pads 81 among the plurality of pads 81 with the base layer 70 interposed therebetween. The thick portion 96 is separated from the four pads 81 by the base layer 70. In addition, one of the four pads 81 may be connected to the thick portion 96 by the via hole 73.

[0075] In the first wiring 91C, two details 95 are separated from each other in the substantially Y direction. A thick portion 96 is located between the two details 95 and is connected to the two details 95. The thick portion 96 is formed in a substantially quadrilateral shape between the two details 95. The width of the thick portion 96 is greater than twice the diameter of the pad 81. Four pads 81 overlapping the thick portion 96 are arranged at intervals in two columns in the Y direction.

[0076] As exemplified by the first wirings 91A, 91B, and 91C, the number of pads 81 overlapping the thick portion 96 is not limited. For example, the thick portion 96 may overlap three, five, or more pads 81, or may overlap one pad 81. In addition, the thick portion 96 may extend in a direction substantially the same as the direction in which the detail 95 extends, may be formed in a quadrilateral, triangular, or other geometric shape, or may be bent.

[0077] Each pair of the second wirings 92 overlaps at least one of the plurality of pads 81 with the base layer 70 interposed therebetween. Further, it is also possible that three or more second wirings 92 overlap the pad 81 with the base layer 70 interposed therebetween.

[0078] In the present embodiment, a pair of second wirings 92 extends substantially in parallel at a position overlapping at least one pad 81. In other words, portions of the two second wirings 92 that extend substantially in parallel overlap the pad 81 with the base layer 70 interposed therebetween. Further, the direction in which the pair of second wirings 92 extends is not limited to this example.

[0079] A pair of second wirings 92 may extend in different directions from each other at a position separated from the pad 81 along the second surface 70b. That is, a pair of second wirings 92 only needs to overlap at least one common pad 81, and may also be two second wirings 92 having no other relevance.

[0080] In the present embodiment, in at least one of the plurality of pairs of second wirings 92, a portion overlapping the pad 81 with the base layer 70 interposed therebetween is thicker than a portion separated from the pad 81 along the second surface 70b. In at least one of the plurality of pairs of second wirings 92, each second wiring 92 has a first edge 97, a second edge 98, and an extension portion 99.

[0081] The first edge 97 faces the other second wiring 92 of the pair. That is, the first edge 97 of one second wiring 92 and the first edge 97 of the other second wiring 92 face each other with a gap therebetween at a position overlapping the pad 81.

[0082] The second edge 98 is located on the opposite side of the first edge 97. The second edge 98 extends substantially in parallel with the first edge 97. The second edge 98 is separated from the pad 81 overlapping the pair of second wirings 92 along the second surface 70b.

[0083] At a position overlapping the pad 81, the interval between the pair of second wirings 92 is about 29 μm. The interval between the pair of second wirings 92 is the distance between the first edge 97 of one second wiring 92 and the first edge 97 of the other second wiring 92.

[0084] The width of the second wiring 92 at a position separated from the pad 81 along the second surface 70b is about 29 μm. This width of the second wiring 92 is the distance between the first edge 97 and the second edge 98. Further, the interval and width of the second wiring 92 are not limited to the above examples.

[0085] The extension portion 99 protrudes from the second edge 98. That is, at the position where the extension portion 99 is provided, the pair of second wirings 92 are respectively thicker than the interval between the pair of second wirings 92. The extension portion 99 overlaps with the pad 81 with the base layer 70 interposed therebetween. In addition, the extension portion 99 may be omitted, and a pair of second wirings 92 having a certain width may overlap with the pad 81.

[0086] The ground plane 86 is set to a ground potential, for example. As Figure 3 shown, the ground plane 86 is separated from the wiring 85. The ground plane 86 overlaps with at least one of the plurality of pads 81 with the base layer 70 interposed therebetween.

[0087] As Figure 5 shown, the first cover layer 74 covers the first surface 70a of the base layer 70 and the wiring 82 of the first conductive layer 71. For example, the adhesive layer 76 mounts the first cover layer 74 on the first surface 70a and the wiring 82.

[0088] A plurality of holes 101 are provided in the first cover layer 74. The plurality of holes 101 penetrate the first cover layer 74. The plurality of pads 81 of the first conductive layer 71 are exposed to the outside of the FPC 37 through the holes 101. The surface of the exposed pad 81 is plated, for example.

[0089] The second cover layer 75 covers the second surface 70b of the base layer 70 and the second conductive layer 72. For example, the adhesive layer 76 mounts the second cover layer 75 on the second surface 70b and the second conductive layer 72.

[0090] The second cover layer 75 is mounted on the reinforcing plate 67 through the adhesive layer 76. The reinforcing plate 67 is located between the actuator module 41 and the second cover layer 75 and maintains the shape of the first connection portion 61.

[0091] The preamplifier 65 has a bottom surface 111 and a plurality of terminals 112. The bottom surface 111 is formed in a rectangular shape (quadrilateral) and faces the mounting portion MP of the FPC 37 at intervals. The plurality of terminals 112 are provided on the bottom surface 111.

[0092] The preamplifier 65 is mounted on the mounting portion MP by, for example, flip chip mounting. The plurality of terminals 112 are respectively connected to the corresponding one of the plurality of pads 81 via the solder S. The solder S is a solder bump.

[0093] As Figure 3As shown, the preamplifier 65 also has a first side surface 115 and a second side surface 116. The first side surface 115 is an end surface of the preamplifier 65 in the -Y direction and extends in the substantially X direction. The X direction is the direction along the first surface 70a and is an example of the first direction. The second side surface 116 is an end surface of the preamplifier 65 in the -X direction and extends in the substantially Y direction. The Y direction is the direction along the first surface 70a and orthogonal (crosses) to the X direction and is an example of the second direction.

[0094] In the present embodiment, all of the plurality of pads 81 respectively overlap with one of the plurality of first wirings 91, one pair of the plurality of pairs of second wirings 92, or the ground plane 86 with the base layer 70 therebetween. Therefore, at the positions where the plurality of pads 81 are provided, the thickness of the FPC 37 is substantially the same. In addition, the pads provided outside the mounting portion MP may not overlap with the second conductive layer 72.

[0095] In the present embodiment, the pads 81 that transmit write signals or read signals among the plurality of pads 81 overlap with, for example, the ground plane 86 with the base layer 70 therebetween. The first wiring 91, the second wiring 92, and the pads 81 that overlap with the first wiring 91 or the second wiring 92 transmit electrical signals different from the write signals and the read signals. Electrical signals different from the write signals and the read signals are, for example, output signals of a contact sensing sensor, control signals of a laser element for heat-assisted magnetic recording (HAMR), control signals of an oscillation element for microwave-assisted magnetic recording (MAMR), or control signals of a heater. In addition, the pads 81, the first wiring 91, and the second wiring 92 are not limited to this example.

[0096] In the present embodiment, the plurality of pads 81 are symmetrically arranged with respect to the center Cx of the preamplifier 65 in the X direction. For example, the plurality of pads 81 are respectively inverted with respect to the center Cx, whereby at least partially overlap with a corresponding one of the pads 81. That is, the two pads 81 arranged for an object may not be completely symmetrically arranged with respect to the center Cx. In addition, the arrangement of the plurality of pads 81 is not limited to this example.

[0097] The plurality of pads 81 include four corner pads 121, 122, 123, and 124. The corner pads 121 to 124 are the four closest to the four corners 111a of the bottom surface 111 of the preamplifier 65 among the plurality of pads 81. The corner pads 121 to 124 may overlap with any of the first wiring 91, the second wiring 92, and the ground plane 86.

[0098] In the present embodiment, the difference between each distance between the four corner pads 121 to 124 and the preamplifier 65 and the average value of the distances between the corner pads 121 to 124 and the preamplifier 65 is within the range of ±8% of the average value.

[0099] For example, the distance between the corner pad 121 and the preamplifier 65 is 47.8 μm, the distance between the corner pad 122 and the preamplifier 65 is 51.8 μm, the distance between the corner pad 123 and the preamplifier 65 is 51.5 μm, and the distance between the corner pad 124 and the preamplifier 65 is 50.9 μm. In this case, the average value is 50.5 μm, and the difference between the distance and the average value is -5.35% to 2.57% of the average value.

[0100] In the HDD 10 involved in the first embodiment described above, the HDD 10 has a magnetic disk 12, a magnetic head 48, an FPC 37, and a preamplifier 65. The magnetic head 48 is configured to read and write information relative to the magnetic disk 12. The FPC 37 has a base layer 70, a first conductive layer 71, and a second conductive layer 72. The first conductive layer is provided on the first surface 70a of the base layer 70. The second conductive layer is provided on the second surface 70b of the base layer 70 located on the opposite side of the first surface 70a. The FPC 37 is electrically connected to the magnetic head 48. The preamplifier 65 is mounted on the FPC 37. The first conductive layer 71 has a plurality of pads 81. The preamplifier 65 has a plurality of terminals 112 connected to the plurality of pads 81 via solder S. The second conductive layer 72 has a plurality of wirings 85. The plurality of wirings 85 include at least one of at least one first wiring 91 (in the present embodiment, a plurality of first wirings 91) and at least one pair of second wirings (in the present embodiment, a plurality of pairs of second wirings 92). The first wiring 91 includes a thin portion 95 and a thick portion 96. The thin portion 95 is separated from the plurality of pads 81 along the second surface 70b. The thick portion 96 overlaps one of the plurality of pads 81 via the base layer 70, is separated from the one pad 81 by the base layer 70, and is thicker than the thin portion 95. The pair of second wirings 92 overlaps one of the plurality of pads 81 via the base layer 70.

[0101] In the case where at least one pad 81 does not overlap with the second conductive layer 72, in the FPC 37, the portion of the pad 81 that does not overlap with the second conductive layer 72 is thinner than the portion of the pad 81 that overlaps with the second conductive layer 72. Therefore, one pad 81 among the plurality of pads 81 that does not overlap with the second conductive layer 72 is farther from the preamplifier 65 than one pad 81 among the plurality of pads 81 that overlaps with the second conductive layer 72. During reflow soldering, the solder S between the pads 81 and the terminals 112 that are separated from each other more strongly generates a surface tension that brings the preamplifier 65 and the FPC 37 closer to each other than the solder S between the pads 81 and the terminals 112 that are closer to each other. If the preamplifier 65 is tilted relative to the FPC 37 due to this imbalance in surface tension, the solder S between the pads 81 and the terminals 112 that are closer to each other may be pressed and spread. However, the HDD 10 of the present embodiment can adjust the thickness of the FPC 37 by overlapping the desired pad 81 with the thick portion 96 of the first wiring 91 or a pair of second wirings 92, thereby suppressing the tilt of the preamplifier 65. By suppressing the tilt of the preamplifier 65, the HDD 10 of the present embodiment can, for example, suppress a short circuit caused by the spread solder S and improve the design flexibility of the FPC 37.

[0102] The plurality of wirings 85 include first wirings 91A, 91B, and 91C. The first wirings 91A, 91B, and 91C respectively overlap with two adjacent pads 81 among the plurality of pads 81 with the base layer 70 interposed therebetween. As a result, compared with the case where the thick portion 96 overlaps with only one pad 81 among the plurality of pads 81, the thick portion 96 becomes larger, and the plurality of pads 81 can be stably supported. Therefore, the HDD 10 of the present embodiment can stably adjust the thickness of the FPC 37.

[0103] The first wiring 91A has two thin portions 95. The two thin portions 95 are separated from the plurality of pads 81 along the second surface 70b, respectively, and are connected to the thick portion 96. The thick portion 96 extends between the two thin portions 95. The two pads 81 are arranged at intervals in the Y direction in which the thick portion 96 extends. As a result, the thick portion 96 does not need to be much thicker than the diameter of one pad 81, and the thickness of the thick portion 96 can be suppressed from affecting the signal transmitted by the first wiring 91A.

[0104] The plurality of wirings 85 include the first wiring 91B. The FPC 37 has a via hole 73. The via hole 73 connects the pad 81B among the two pads 81 to the thick portion 96 of the first wiring 91B. That is, the thick portion 96 supports a so-called via pad. As a result, the HDD 10 of the present embodiment can improve the freedom of the wiring 85 of the FPC 37.

[0105] The width W2 of the thick portion 96 is the same as or wider than the width of one pad 81. Thus, the thick portion 96 can stably support the pad 81. Therefore, the HDD 10 of the present embodiment can stably adjust the thickness of the FPC 37.

[0106] The plurality of wirings 85 include at least a pair of second wirings 92. The pair of second wirings 92 extend in parallel at a position overlapping with one pad 81. Thus, the second wiring 92 can stably support the pad 81. Therefore, the HDD 10 of the present embodiment can stably adjust the thickness of the FPC 37.

[0107] The portion of the pair of second wirings 92 that overlaps with one pad 81 with the base layer 70 therebetween is thicker than the portion that is separated from the plurality of pads 81 along the second surface 70b. Thus, the second wiring 92 can stably support the pad 81. Therefore, the HDD 10 of the present embodiment can stably adjust the thickness of the FPC 37.

[0108] Each second wiring 92 has a first edge 97, a second edge 98, and an extension portion 99. The first edge 97 faces the other second wiring 92 of the pair. The second edge 98 is located on the opposite side of the first edge 97. The extension portion 99 protrudes from the second edge 98 and overlaps with one pad 81 with the base layer 70 therebetween. Thus, the HDD 10 of the present embodiment can suppress the pair of extension portions 99 from approaching each other too much, and further can suppress the short circuit of the second wiring 92 or the influence of the change in the interval of the second wiring 92 on the signal transmitted by the second wiring 92.

[0109] The preamplifier 65 is electrically connected to the head 48, outputs a write signal to the head 48, and inputs a read signal from the head 48. The write signal corresponds to the information written by the head 48 to the disk 12. The read signal corresponds to the information read by the head 48 from the disk 12. With the increase in the number of disks 12 and the development of the recording technology of the head 48, the number and density of the pads 81 for mounting the preamplifier 65 also increase. Therefore, in the case where the preamplifier 65 is tilted, a short circuit caused by the extended solder S may occur. However, the HDD 10 of the present embodiment adjusts the thickness of the FPC 37, and further can suppress the tilt of the preamplifier 65. The HDD 10 of the present embodiment can suppress the short circuit caused by the extended solder S by suppressing the tilt of the preamplifier 65.

[0110] The plurality of first wirings 91 and the plurality of pairs of second wirings 92 transmit electrical signals different from the write signal and the read signal. Thus, the HDD 10 of the present embodiment can suppress the change in the impedance characteristics that affects the read signal or the write signal when the plurality of first wirings 91 or the plurality of pairs of second wirings 92 overlap with the pads 81.

[0111] The second conductive layer 72 has a ground plane 86. All of the plurality of pads 81 overlap, with the substrate layer 70 therebetween, one of the plurality of first wirings 91, one pair of the plurality of pairs of second wirings 92, or the ground plane 86. Accordingly, the thickness of the FPC 37 becomes substantially equal at each position where the plurality of pads 81 are provided. Therefore, the HDD 10 of the present embodiment can suppress the tilt of the preamplifier 65.

[0112] The preamplifier 65 has a quadrangular bottom surface 111 facing the FPC 37. The plurality of pads 81 include four corner pads 121, 122, 123, and 124 that are closest to the four corners 111a of the bottom surface 111. The difference between each distance between the four corner pads 121 to 124 and the preamplifier 65 and the average value of the distances between the four corner pads 121 to 124 and the preamplifier 65 is within the range of ±8% of the average value. That is, the preamplifier 65 is hardly tilted. The HDD 10 of the present embodiment suppresses the tilt of the preamplifier 65 by including the first wiring 91 and the plurality of pairs of second wirings 92.

[0113] (Second Embodiment)

[0114] Next, the second embodiment will be described with reference to Figure 6 In addition, in the description of the following plurality of embodiments, sometimes, for components having the same functions as the components already described, the same reference numerals as those of the already described components are given, and the description is omitted. In addition, the plurality of components with the same reference numerals are not limited to having all common functions and properties, and may have different functions and properties corresponding to each embodiment.

[0115] Figure 6 is an exemplary plan view showing the mounting portion MP of the FPC 37 according to the second embodiment. As Figure 6 shown, in the FPC 37 of the second embodiment, instead of the second conductive layer 72, there is a second conductive layer 201. The second conductive layer 201 is substantially equal to the second conductive layer 72 except for the points described below.

[0116] The entirety of the second conductive layer 201 is separated from the plurality of pads 81 along the second surface 70b. For example, the plurality of wirings 85 extend while being separated from the plurality of pads 81. The plurality of pads 81 do not include via pads. And an opening 211 is provided in the ground plane 86. The opening 211 is a hole or a cut. In the projection plane orthogonal to the first surface 70a as Figure 6 shown, at least one of the plurality of pads 81 is disposed inside the opening 211.

[0117] In the HDD 10 of the second embodiment described above, the entire second conductive layer 201 is separated from the plurality of pads 81 along the second surface 70b. As a result, at each position where the plurality of pads 81 are provided, the thickness of the FPC 37 becomes substantially equal. Therefore, the HDD 10 of the present embodiment can suppress the inclination of the preamplifier 65. By suppressing the inclination of the preamplifier 65, the HDD 10 of the present embodiment can, for example, suppress a short circuit caused by the extended solder S and can increase the degree of freedom in the design of the FPC 37.

[0118] (Third Embodiment)

[0119] Next, regarding the third embodiment, refer to Figure 7 for description. Figure 7 is an exemplary plan view showing the mounting portion MP of the FPC 37 according to the third embodiment. As Figure 7 shown, in the FPC 37 of the third embodiment, the second conductive layer 301 is provided instead of the second conductive layer 72. The second conductive layer 301 is substantially equal to the second conductive layer 72 except for the points described below.

[0120] The wiring 85 of the second conductive layer 301 has a plurality of first wirings 91, a plurality of pairs of second wirings 92, and a plurality of third wirings 311. The plurality of third wirings 311 are separated from the plurality of pads 81 along the second surface 70b. And an opening 211 is provided in the ground plane 86.

[0121] The plurality of pads 81 include a plurality of first pads 321 and a plurality of second pads 322. The plurality of first pads 321 overlap the second conductive layer 301 with the base layer 70 interposed therebetween, respectively. For example, the plurality of first pads 321 overlap one of the plurality of first wirings 91, a pair of the plurality of pairs of second wirings 92, or the ground plane 86, respectively. The plurality of second pads 322 are separated from the second conductive layer 301 along the second surface 70b, respectively.

[0122] The plurality of first pads 321 are arranged symmetrically with respect to the center Cx. And the plurality of first pads 321 are arranged symmetrically with respect to the center Cy of the preamplifier 65 in the Y direction. For example, the plurality of first pads 321 are inverted with respect to the center Cy, respectively, so that at least a part of each first pad 321 overlaps with a corresponding one of the first pads 321. The plurality of second pads 322 are arranged symmetrically with respect to the center Cx. And the plurality of second pads 322 are arranged symmetrically with respect to the center Cy.

[0123] In the HDD 10 of the third embodiment described above, the preamplifier 65 has a first side surface 115 extending in the X direction along the first surface 70a and a second side surface 116 extending in the Y direction along the first surface 70a and intersecting the X direction. A plurality of first pads 321 among the plurality of pads 81 that overlap the second conductive layer 301 with the base layer 70 therebetween are symmetrically arranged with respect to the center Cx of the preamplifier 65 in the X direction. A plurality of second pads 322 among the plurality of pads 81 that are separated from the second conductive layer 301 along the second surface 70b are also symmetrically arranged with respect to the center Cx of the preamplifier 65 in the X direction. Thus, the surface tension generated by the solder S during reflow soldering is distributed substantially symmetrically with respect to the center Cx of the preamplifier 65 in the X direction. Therefore, the HDD 10 of the present embodiment can suppress the inclination of the preamplifier 65.

[0124] The plurality of first pads 321 are symmetrically arranged with respect to the center Cy of the preamplifier 65 in the Y direction. The plurality of second pads 322 are also symmetrically arranged with respect to the center Cy of the preamplifier 65 in the Y direction. Thus, the surface tension generated by the solder S during reflow soldering is distributed substantially symmetrically with respect to the center Cx of the preamplifier 65 in the X direction and substantially symmetrically with respect to the center Cy of the preamplifier 65 in the Y direction. Therefore, the HDD 10 of the present embodiment can suppress the inclination of the preamplifier 65.

[0125] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in the claims and its equivalent scope.

[0126] Description of Reference Numerals

[0127] 10…Hard disk drive (HDD), 12…Disk, 37…Flexible printed circuit board (FPC), 48…Head, 65…Pre-amplifier, 70…Base layer, 70a…First surface, 70b…Second surface, 71…First conductive layer, 72, 201, 301…Second conductive layer, 73…Through hole, 81, 81A, 81B…Pad, 85…Wiring, 86…Ground plane, 91, 91A, 91B, 91C…First wiring, 92…Second wiring, 95…Detail part, 96…Coarse part, 97…First edge, 98…Second edge, 99…Extension part, 111…Bottom surface, 111a…Corner, 112…Terminal, 115…First side surface, 116…Second side surface, 121, 122, 123, 124…Corner pad, 321…First pad, 322…Second pad, S…Solder, Cx, Cy…Center.

Claims

1. A disk device, wherein: have: disk; a magnetic head configured to read and write information relative to the magnetic disk; a flexible printed circuit board electrically connected to the magnetic head, comprising an insulating layer, a first conductive layer disposed on a first surface of the insulating layer, and a second conductive layer disposed on a second surface of the insulating layer, the second surface being located on the opposite side of the first surface; and electronic components mounted on the flexible printed circuit board, The first conductive layer has a plurality of pads. The electronic component has a plurality of terminals connected to the plurality of pads via solder. The second conductive layer has a plurality of wirings, The multiple wirings include at least one of a first wiring or multiple first wirings, a pair of second wirings or multiple pairs of second wirings, the first wiring or each of the multiple first wirings has a first part and a second part, the first part is separated from the multiple pads along the second surface, the second part overlaps with one of the multiple pads via the insulating layer and is separated from the one pad by the insulating layer, the second part is thicker than the first part, and the pair of second wirings or each pair of the multiple pairs of second wirings overlaps with one of the multiple pads via the insulating layer.

2. The disk device according to claim 1, wherein The plurality of wirings include the first wiring or the plurality of first wirings, The first wiring or the second portion of at least one of the plurality of first wirings overlaps two adjacent pads of the plurality of pads via the insulating layer.

3. The disk device according to claim 2, wherein: The first wiring or each of the plurality of first wirings further includes a third portion, the third portion being separated from the plurality of pads along the second surface and connected to the second portion, The first part is connected to the second part, The second portion extends between the first portion and the third portion, The two pads are arranged at a distance from each other in the direction in which the second portion extends.

4. The disk device according to claim 2, wherein: The plurality of wirings include the first wiring or the plurality of first wirings, The flexible printed circuit board has a through hole connecting one of the two pads and the second portion.

5. The disk device according to claim 1, wherein The plurality of wirings include the first wiring or the plurality of first wirings, The width of the second portion is the same as or wider than the width of the one pad.

6. The disk device according to claim 1, wherein The plurality of wirings include the pair of second wirings or the plurality of pairs of second wirings, The pair of second wirings or at least one pair of the plurality of pairs of second wirings extends in parallel at a position overlapping with the one pad.

7. The disk device according to claim 1, wherein The plurality of wirings include the pair of second wirings or the plurality of pairs of second wirings, In the pair of second wirings or at least one of the plurality of pairs of second wirings, a portion overlapping the one pad via the insulating layer is thicker than a portion separated from the plurality of pads along the second surface.

8. The disk device according to claim 7, wherein: In the pair of second wirings or at least one pair of the multiple pairs of second wirings, each of the second wirings has a first edge, a second edge and an extension portion, the first edge faces the other second wiring in the pair, the second edge is located on the opposite side of the first edge, and the extension portion protrudes from the second edge and overlaps with the one pad via the insulating layer.

9. The disk device according to claim 1, wherein The electronic component is electrically connected to the magnetic head, outputs a write signal corresponding to information written by the magnetic head to the magnetic disk to the magnetic head, and receives a read signal corresponding to information read by the magnetic head from the magnetic disk from the magnetic head.

10. The disk device according to claim 9, wherein The first wiring, the plurality of first wirings, the pair of second wirings, and the plurality of pairs of second wirings transmit an electrical signal different from the write signal and the read signal.

11. The disk device according to claim 1, wherein The second conductive layer has a ground plane, All of the plurality of pads overlap the first wiring, one of the plurality of first wirings, the pair of second wirings, a pair of second wirings of the plurality of pairs of second wirings, or the ground plane, respectively, via the insulating layer.

12. The disk device according to claim 1, wherein The electronic component has a quadrilateral bottom surface facing the flexible printed circuit board, The plurality of pads include four corner pads closest to the four corners of the bottom surface, A difference between each distance between the four corner pads and the electronic component and an average value of the distances between the four corner pads and the electronic component is within a range of ±8% of the average value.

13. The disk device according to claim 1, wherein The electronic component has a first side surface extending in a first direction along the first surface, and a second side surface extending in a second direction along the first surface and intersecting the first direction. A plurality of first pads among the plurality of pads, each of which overlaps with the second conductive layer via the insulating layer, are arranged symmetrically with respect to the center of the electronic component in the first direction. A plurality of second pads, among the plurality of pads, each of which is separated from the second conductive layer along the second surface, are arranged symmetrically with respect to the center of the electronic component in the first direction.

14. The disk device according to claim 13, wherein The plurality of first pads are arranged symmetrically with respect to the center of the electronic component in the second direction, The plurality of second pads are arranged symmetrically with respect to a center of the electronic component in the second direction.

15. A disk device, wherein: have: disk; a magnetic head configured to read and write information relative to the magnetic disk; a flexible printed circuit board electrically connected to the magnetic head, comprising an insulating layer, a first conductive layer disposed on a first surface of the insulating layer, and a second conductive layer disposed on a second surface of the insulating layer, the second surface being located on the opposite side of the first surface; and electronic components mounted on the flexible printed circuit board, The first conductive layer has a plurality of pads. The electronic component has a plurality of terminals connected to the plurality of pads via solder. The entire second conductive layer is separated from the plurality of pads along the second surface.

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