electronic machinery

Abstract

To provide an electronic device capable of increasing a creepage distance between pads.SOLUTION: An electronic device includes a wall and a substrate. The substrate includes an organic compound layer, a first surface of the organic compound layer attached to the wall, a second surface of the organic compound layer provided opposite the first surface, first wiring provided on the second surface, second wiring provided on the second surface, a first pad connected to the first wiring, and a second pad connected to the second wiring and away from the first pad. An opening is provided to penetrate the organic compound layer to open to the first surface and the second surface between the first pad and the second pad.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to an electronic device. [Background technology]

[0002] The electronic device has a substrate, such as a flexible printed circuit board, on which a plurality of pads are provided. The pads are bonded to terminals of an electronic component by, for example, solder or a conductive adhesive, or a compression connector of a testing device is temporarily pressed against the pads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-76070 Summary of the Invention [Problem to be solved by the invention]

[0004] The metal contained in the pads can ionize due to corrosion and travel along the surface of the board. If the corroded metal electrically connects adjacent pads, it can cause a short circuit in the board circuit. On the other hand, if the creepage distance between adjacent pads is long, it will take a long time for a short circuit to occur between the adjacent pads.

[0005] One example of a problem to be solved by the present invention is to provide an electronic device that can increase the creepage distance between pads. [Means for solving the problem]

[0006] An electronic device according to an embodiment includes a wall, a substrate, and , the first protrusion andThe substrate has an organic compound layer, a first surface of the organic compound layer attached to the wall, a second surface of the organic compound layer located opposite to the first surface, a first wiring provided on the second surface, a second wiring provided on the second surface, a first pad connected to the first wiring, and a second pad connected to the second wiring and spaced apart from the first pad, and an opening is provided that penetrates the organic compound layer and opens to the first surface and the second surface between the first pad and the second pad. The first protrusion protrudes from the wall through the opening. The first pad extends in a first direction along the second surface and has a first edge facing the second pad. The second pad extends in the first direction and has a second edge facing the first edge. The opening is located between the entire first edge and the second edge. The wall is provided with a hole communicating with the opening. The first protrusion is spaced apart from the first edge and the second edge in the first direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an exemplary perspective view showing an exploded hard disk drive (HDD) according to the first embodiment. [Figure 2] FIG. 2 is an exemplary bottom view showing a part of the HDD of the first embodiment. [Figure 3] FIG. 3 is an exemplary plan view illustrating a portion of the external FPC of the first embodiment. [Figure 4] FIG. 4 is an exemplary cross-sectional view showing a part of the HDD of the first embodiment taken along line F4-F4 in FIG. [Figure 5] FIG. 5 is an exemplary cross-sectional view showing a portion of the bottom wall and a portion of the external FPC of the first embodiment. [Figure 6] FIG. 6 is an exemplary cross-sectional view showing a pad covered with a cover according to the first embodiment. [Figure 7] FIG. 7 is an exemplary plan view showing a portion of an external FPC according to a first modified example of the first embodiment. [Figure 8] FIG. 8 is an exemplary plan view showing a portion of an external FPC according to a second modified example of the first embodiment. [Figure 9] FIG. 9 is an exemplary plan view showing a portion of an external FPC according to the second embodiment. [Figure 10] FIG. 10 is an exemplary cross-sectional view showing a part of the HDD of the second embodiment taken along line F10-F10 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) The first embodiment will be described below with reference to FIGS. 1 to 8. In this specification, components according to the embodiment and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be described using expressions different from those in this specification.

[0009] 1 is an exemplary exploded perspective view of a hard disk drive (HDD) 10 according to the first embodiment. The HDD 10 is an example of an electronic device, and may also be referred to as a storage device, an external storage device, a disk device, or a magnetic disk device. Note that the electronic device is not limited to the HDD 10, and may be other devices.

[0010] 1, the HDD 10 includes a housing 11, multiple magnetic disks 12, a spindle motor 13, multiple magnetic heads 14, a head stack assembly (HSA) 15, a voice coil motor (VCM) 16, a ramp load mechanism 17, an internal flexible printed circuit board (FPC) 18, and a printed circuit board (PCB) 19. The spindle motor 13 is an example of an electrical component. The magnetic heads 14 and the internal FPC 18 may be included in the HSA 15.

[0011] The housing 11 has a base 21, an inner cover 22, and an outer cover 23. However, the housing 11 is not limited to this example. The base 21 is formed in a substantially rectangular box shape with an inner chamber S provided inside the base 21. The inner chamber S is open to the outside of the base 21. The housing 11 accommodates multiple magnetic disks 12, a spindle motor 13, multiple magnetic heads 14, an HSA 15, a VCM 16, a ramp load mechanism 17, and an internal FPC 18 in the inner chamber S.

[0012] The base 21 has a bottom wall 25 and side walls 26. The bottom wall 25 is an example of a wall. The bottom wall 25 is formed in a substantially rectangular (quadrilateral) plate shape. The side walls 26 protrude from the edges of the bottom wall 25 and are formed in a substantially rectangular frame shape. The bottom wall 25 and the side walls 26 are integrally formed. The inner cover 22 is attached to the end of the side walls 26, for example, by screws, and closes the inner chamber S. The outer cover 23 covers the inner cover 22 and is attached to the end of the side walls 26, for example, by welding.

[0013] An air vent 27 is provided in the inner cover 22. Furthermore, an air vent 28 is provided in the outer cover 23. After components are attached inside the base 21 and the inner cover 22 and the outer cover 23 are attached to the base 21, air inside the housing 11 is evacuated through the air vents 27 and 28. Furthermore, the inside of the housing 11 is filled with a gas other than air.

[0014] The gas filled inside the housing 11 is, for example, a low-density gas with a density lower than air, an inert gas with low reactivity, or the like. For example, helium is filled inside the housing 11. Note that other fluids may also be filled inside the housing 11. Furthermore, the inside of the housing 11 may be kept at a vacuum, a low pressure close to a vacuum, or a negative pressure lower than atmospheric pressure.

[0015] The vent hole 28 of the outer cover 23 is closed by a seal 29. The seal 29 airtightly seals the vent hole 28, preventing the fluid filled inside the housing 11 from leaking through the vent hole 28.

[0016] The plurality of magnetic disks 12 are stacked with a gap therebetween. A spindle motor 13 rotates the plurality of magnetic disks 12. The plurality of magnetic disks 12 are held on the hub of the spindle motor 13 by, for example, a clamp spring.

[0017] Each of the plurality of magnetic heads 14 records and reproduces information on a corresponding one of the plurality of magnetic disks 12. In other words, each of the plurality of magnetic heads 14 reads and writes information from and to one of the plurality of magnetic disks 12.

[0018] A plurality of magnetic heads 14 are mounted on the HSA 15. The VCM 16 rotates the HSA 15 and positions it at a desired position. When the magnetic heads 14 move to the outermost periphery of the magnetic disk 12 as the HSA 15 is rotated by the VCM 16, the ramp load mechanism 17 holds the magnetic heads 14 at a position spaced apart from the magnetic disk 12.

[0019] One end of the internal FPC 18 is electrically connected to the magnetic head 14 via the HSA 15. The other end of the internal FPC 18 is connected to a connector provided on the bottom wall 25, for example.

[0020] The PCB 19 is, for example, a rigid board such as a glass epoxy board, and is a multi-layer board or a build-up board, etc. The PCB 19 is disposed outside the housing 11 and attached to the bottom wall 25.

[0021] Various electronic components are mounted on the PCB 19, such as a relay connector connected to the internal FPC 18, an interface (I / F) connector connected to a host computer, and a controller that controls the operation of the HDD 10. The relay connector is electrically connected to the internal FPC 18 via a connector provided on the bottom wall 25.

[0022] 2 is an exemplary bottom view showing a portion of the HDD 10 of the first embodiment. As shown in FIG. 2, the HDD 10 further includes an external FPC 30. The external FPC 30 is an example of a substrate. Note that the substrate is not limited to an FPC, and may be another substrate such as a PCB.

[0023] The external FPC 30 is disposed outside the housing 11 and attached to the bottom wall 25. The external FPC 30 electrically connects the spindle motor 13 and the PCB 19. For example, a host computer supplies power to the spindle motor 13 via the PCB 19 and the external FPC 30.

[0024] FIG. 3 is an exemplary plan view showing a portion of the external FPC 30 of the first embodiment. FIG. 4 is an exemplary cross-sectional view showing a portion of the HDD 10 of the first embodiment along line F4-F4 in FIG. 3. As shown in each drawing, for convenience, an X-axis, a Y-axis, and a Z-axis are defined in this specification. The X-axis, the Y-axis, and the Z-axis are perpendicular to one another. The Z-axis is provided along the thickness of the external FPC 30.

[0025] Furthermore, in this specification, the X direction, Y direction, and Z direction are defined. The X direction is a direction along the X axis, and includes the +X direction indicated by the X axis arrow and the -X direction opposite to the X axis arrow. The Y direction is a direction along the Y axis, and includes the +Y direction indicated by the Y axis arrow and the -Y direction opposite to the Y axis arrow. The Z direction is a direction along the Z axis, and includes the +Z direction indicated by the Z axis arrow and the -Z direction opposite to the Z axis arrow.

[0026] 4, the bottom wall 25 of the base 21 has an outer surface 25a. The outer surface 25a is located outside the housing 11 and is separated from the inner chamber S by the bottom wall 25. The outer surface 25a is formed, for example, to be substantially flat and faces substantially in the +Z direction. Note that the outer surface 25a may have irregularities.

[0027] The external FPC 30 is attached to the outer surface 25a of the bottom wall 25. The external FPC 30 has an organic compound layer 31, a conductive layer 32, and a cover layer 33. However, the external FPC 30 is not limited to this example.

[0028] 5 is an exemplary cross-sectional view showing a portion of the bottom wall 25 and a portion of the external FPC 30 of the first embodiment. As shown in Fig. 5, the organic compound layer 31 has a base layer 35 and an adhesive layer 36. The base layer 35 is an example of an insulator layer.

[0029] The base layer 35 is an insulating film made of a synthetic resin such as polyimide or polyester. The base layer 35 has a lower surface 35a and an upper surface 35b. The upper surface 35b is an example of a second surface. Note that the terms "upper" and "lower" in this embodiment are used for convenience with reference to FIGS. 4 and 5, and do not limit the position, direction, usage, or other conditions.

[0030] The lower surface 35a is formed to be substantially flat and faces substantially in the -Z direction. The lower surface 35a faces the outer surface 25a of the bottom wall 25 via the adhesive layer 36. The upper surface 35b is located on the opposite side of the lower surface 35a. The upper surface 35b is formed to be substantially flat and faces substantially in the +Z direction.

[0031] The adhesive layer 36 is, for example, an epoxy resin adhesive. The adhesive layer 36 is interposed between the outer surface 25a of the bottom wall 25 and the lower surface 35a of the base layer 35. The adhesive layer 36 has a lower surface 36a and an upper surface 36b. The lower surface 36a is an example of a first surface.

[0032] The lower surface 36a is formed to be substantially flat and faces substantially in the -Z direction. The lower surface 36a is attached to the outer surface 25a of the bottom wall 25. The upper surface 36b is located on the opposite side of the lower surface 36a. The upper surface 36b is formed to be substantially flat and faces substantially in the +Z direction. The upper surface 36b is attached to the lower surface 35a of the base layer 35. In other words, the adhesive layer 36 bonds the lower surface 35a of the base layer 35 to the outer surface 25a of the bottom wall 25.

[0033] An upper surface 35b of the base layer 35 and a lower surface 36a of the adhesive layer 36 are not covered by other parts of the organic compound layer 31 and form the surface of the organic compound layer 31. The upper surface 35b is provided at an end of the organic compound layer 31 in the +Z direction. The lower surface 36a is provided at an end of the organic compound layer 31 in the -Z direction. In the entire organic compound layer 31, the upper surface 35b is located opposite the lower surface 36a.

[0034] The external FPC 30 may be a multi-layer substrate. That is, the organic compound layer 31 may further include multiple layers interposed between the base layer 35 and the adhesive layer 36. For example, multiple base layers and multiple adhesive layers may be provided between the base layer 35 and the adhesive layer 36, and wiring may be provided on the multiple base layers. Furthermore, through holes may be provided in the multiple base layers.

[0035] The conductive layer 32 is provided on an upper surface 35b of the base layer 35. An adhesive layer may be interposed between the base layer 35 and the conductive layer 32. As shown in FIG. 3, the conductive layer 32 has a plurality of wirings 41, 42, 43, and 44 and a plurality of pads 45, 46, 47, and 48. The wiring 41 is an example of a first wiring. The wiring 42 is an example of a second wiring. The pad 45 is an example of a first pad. The pad 46 is an example of a second pad.

[0036] Each of the plurality of wires 41, 42, 43, and 44 electrically connects the spindle motor 13 and the PCB 19. For example, the spindle motor 13 is a three-phase motor, and is supplied with power through the plurality of wires 41, 42, and 43.

[0037] The pad 45 is connected to the wiring 41. The pad 46 is connected to the wiring 42. The pad 47 is connected to the wiring 43. The pad 48 is connected to the wiring 44. The pads 45, 46, 47, and 48 are spaced apart from one another.

[0038] The pads 45 and 46 are adjacent to each other in the Y direction. The pad 46 is spaced apart from the pad 45 in the +Y direction. The +Y direction is a direction along the top surface 35b and is an example of the second direction.

[0039] The pads 47 and 48 are adjacent to each other in the Y direction. Furthermore, the pads 47 and 48 and the pads 45 and 46 are adjacent to each other in the X direction. The pad 47 is spaced apart from the pad 45 in the +X direction. The pad 48 is spaced apart from the pad 46 in the +X direction and from the pad 47 in the +Y direction.

[0040] Each of the pads 45, 46, 47, and 48 is formed in a substantially rectangular shape. Note that the shapes of the pads 45, 46, 47, and 48 are not limited to this example. The substantially rectangular pads 45, 46, 47, and 48 have, for example, four straight edges that form the sides of the rectangle.

[0041] Pad 45 has edges 45a and 45b. Edge 45a is one of four edges of pad 45 and is an example of a first edge. Edge 45a extends linearly in the X direction (+X direction and -X direction) and faces the +Y direction. The -X direction is a direction along top surface 35b and is an example of a first direction. Edge 45a of pad 45 faces pad 46 via a gap.

[0042] Edge 45b of pad 45 is another of the four edges of pad 45. Edge 45b extends linearly in the −Y direction from the end of edge 45a in the +X direction and faces the +X direction. Edge 45b of pad 45 faces wiring 42 with a gap therebetween.

[0043] The pad 46 has an edge 46a. The edge 46a is one of the four edges of the pad 46 and is an example of a second edge. The edge 46a extends linearly in the X direction and faces the -Y direction. The edge 46a faces the edge 45a of the pad 45 via a gap.

[0044] Pad 47 has an edge 47a. Edge 47a is one of four edges of pad 47. Edge 47a extends linearly in the X direction and faces in the +Y direction. Pad 48 has an edge 48a. Edge 48a is one of four edges of pad 48. Edge 48a extends linearly in the X direction and faces in the -Y direction. Edge 47a and edge 48a face each other with a gap between them.

[0045] As shown in FIG. 5, each of pads 45, 46, 47, and 48 has a metal layer 51 and a gold plating 52. The metal layer 51 of pad 45 is an example of a first metal layer. The gold plating 52 of pad 45 is an example of a first gold plating. The metal layer 51 of pad 46 is an example of a second metal layer. The gold plating 52 of pad 46 is an example of a second gold plating.

[0046] The metal layer 51 is made of copper and is integral with the corresponding wirings 41, 42, 43, and 44. Therefore, the metal layer 51 of the pads 45, 46, 47, and 48 is provided on the upper surface 35b of the base layer 35 and is connected to the corresponding wirings 41, 42, 43, and 44. The metal layer 51 may contain nickel. Gold plating 52 covers the metal layer 51.

[0047] 4 is an insulating film made of a synthetic resin such as polyimide or polyester. The cover layer 33 covers the upper surface 35b of the base layer 35 and the wiring 41, 42, 43, and 44. The cover layer 33 may also cover a portion of the pads 45, 46, 47, and 48.

[0048] 3, a plurality of exposure holes 61, 62 are provided in the cover layer 33. The exposure holes 61, 62 penetrate the cover layer 33 substantially in the Z direction. The exposure hole 61 exposes at least a portion of the pads 45, 46 and a portion of the upper surface 35b of the cover layer 33 to the outside of the external FPC 30.

[0049] The exposure hole 62 is spaced apart from the exposure hole 61. The exposure hole 62 exposes at least a portion of the pads 47, 48 and another portion of the upper surface 35b of the cover layer 33 to the outside of the external FPC 30.

[0050] A plurality of openings 65, 66 are provided in the organic compound layer 31. The openings 65, 66 may also be referred to as holes, holes, grooves, slits, or through-holes, for example. As shown in Fig. 5, each of the openings 65, 66 penetrates the organic compound layer 31 substantially in the Z direction and opens to the upper surface 35b and the lower surface 36a. That is, each of the openings 65, 66 penetrates the base layer 35 and the adhesive layer 36.

[0051] The opening 65 opens in the upper surface 35b between the pad 45 and the pad 46. The opening 65 is adjacent to the pads 45 and 46. As shown in FIG. 3, the opening 65 in this embodiment is formed in a substantially L-shape and has two portions 68 and 69. One portion 68 is located between the entire edge 45a of the pad 45 and at least a part of the edge 46a of the pad 46, and extends in the X direction. Furthermore, the other portion 69 is located between the entire edge 45b of the pad 45 and a part of the wiring 42, and extends in the Y direction. Note that the opening 65 is not limited to this example. The opening 66 is located between the edge 47a of the pad 47 and the edge 48a of the pad 48, and extends in the X direction.

[0052] 5, the width of one portion 68 of the opening 65 is approximately equal to the distance between the pads 45 and 46. An edge 68a of the portion 68 is located at approximately the same position in the Y direction as the edge 45a of the pad 45 and the edge 46a of the pad 46. Note that the width of the portion 68 may be shorter than the distance between the pads 45 and 46.

[0053] The opening 65 is exposed to the outside of the external FPC 30 through the exposure hole 61. In other words, the opening 65 communicates with the exposure hole 61. The opening 66 is exposed to the outside of the external FPC 30 through the exposure hole 62. In other words, the opening 66 communicates with the exposure hole 62.

[0054] As shown in Fig. 3, holes 71 and 72 are provided in the outer surface 25a of the bottom wall 25. As shown in Fig. 5, the holes 71 and 72 are recessed from the outer surface 25a in approximately the -Z direction. The holes 71 and 72 do not penetrate the bottom wall 25, but are recesses with bottoms. Therefore, the holes 71 and 72 do not connect the inner chamber S of the housing 11 to the outside.

[0055] 3, in this embodiment, the hole 71 is formed in a substantially L-shape and has two portions 74 and 75. One portion 74 is located between the entire edge 45a of the pad 45 and at least a part of the edge 46a of the pad 46, and extends in the X direction. Furthermore, the other portion 75 is located between the entire edge 45b of the pad 45 and a part of the wiring 42, and extends in the Y direction.

[0056] 5, hole 71 communicates with opening 65. One portion 74 of hole 71 communicates with one portion 68 of opening 65. The other portion 75 of hole 71 communicates with the other portion 69 of opening 65. Hole 72 communicates with opening 66.

[0057] In the Y direction (+Y direction), the length (width) of one portion 74 of hole 71 is longer than the length (width) of one portion 68 of opening 65. Therefore, one portion 74 of hole 71 has recesses 77, 78 recessed in the Y direction from an edge 68a of one portion 68 of opening 65. Recess 77 is a portion recessed in the -Y direction from edge 68a. Recess 78 is a portion recessed in the +Y direction from edge 68a.

[0058] In the X direction, the length of the other portion 75 of the hole 71 is longer than the length of the other portion 69 of the opening 65. Furthermore, in the Y direction, the length of the hole 72 is longer than the length of the opening 66. Note that the holes 71 and 72 are not limited to this example.

[0059] In the Z direction, the length (depth) of the hole 71 is longer than the length (thickness) of the adhesive layer 36. In addition, in the Z direction, the depth of the hole 71 is longer than the thickness of the base layer 35. On the other hand, in the Z direction, the depth of the hole 71 is the same as or slightly shorter than the thickness of the organic compound layer 31.

[0060] For example, the depth of the hole 71 is approximately 37 μm, the thickness of the base layer 35 is approximately 20 μm, and the thickness of the adhesive layer 36 is approximately 18 μm. Furthermore, the thickness of the conductive layer 32 is approximately 18 μm. However, each dimension is not limited to this example.

[0061] 3, the base 21 further has a protrusion 79. The protrusion 79 is an example of a first protrusion. The protrusion 79 protrudes from the outer surface 25a of the bottom wall 25 in approximately the +Z direction. The protrusion 79 is inserted into the opening 65 of the organic compound layer 31.

[0062] The protrusion 79 is spaced in the X direction (-X direction) from the edges 45a, 46a of the pads 45, 46. For example, one portion 68 of the opening 65 extends in the -X direction beyond the region between the pads 45, 46. The protrusion 79 is inserted into the portion 68 outside the region between the pads 45, 46.

[0063] The width of the protrusion 79 is slightly shorter than the width of the portion 68. Therefore, the protrusion 79 can protrude from the bottom wall 25 through the portion 68. The shape of the protrusion 79 may be a rectangular parallelepiped, a cylinder, or another shape. The protrusion 79 positions the external FPC 30 with respect to the bottom wall 25, for example, when assembling the HDD 10.

[0064] As shown in FIG. 5 , the base 21 has a base portion 81 and a coating 82. The base portion 81 is made of a metal material such as an aluminum alloy. The coating 82 is an insulating paint that covers the base portion 81. The coating 82 forms the surface of the protrusion 79. Therefore, even if the protrusion 79 comes into contact with the pads 45 and 46, it is possible to prevent a short circuit from occurring.

[0065] 4, for example, a testing device 90 is used to test the supply of power to the spindle motor 13. The testing device 90 has a plurality of compression connectors 91. The plurality of compression connectors 91 are, for example, gold-plated metal terminals, and are elastically deformable.

[0066] During testing, the multiple compression connectors 91 contact at least two of the pads 45, 46, 47, and 48 and are electrically connected to the corresponding wirings 41, 42, 43, and 44. In this way, the testing equipment 90 tests, for example, the electrical continuity between the spindle motor 13 and the PCB 19 via the wirings 41, 42, 43, and 44. The bottom wall 25 supports the external FPC 30 against which the compression connectors 91 are pressed.

[0067] The pads 45, 46, 47, and 48 are positioned to correspond to the compression connectors 91 of the testing equipment 90. The compression connectors 91 contact the approximate centers of the corresponding pads 45, 46, 47, and 48. Because the protrusions 79 are far from the centers of the pads 45, 46, 47, and 48, interference with the compression connectors 91 can be suppressed.

[0068] As described above, the pads 45, 46, 47, and 48 of this embodiment are provided to allow temporary contact with the compression connector 91 of the testing equipment 90. For this reason, no components are mounted on the pads 45, 46, 47, and 48, and they are not covered with solder. However, the pads 45, 46, 47, and 48 are not limited to this example, and components may be mounted on them.

[0069] 6 is an exemplary cross-sectional view showing the pads 45, 46 covered by the cover 100 of the first embodiment. As shown in Fig. 6, the HDD 10 may further include a cover 100. The cover 100 covers the pads 45, 46, 47, 48 and protects the pads 45, 46, 47, 48 from corrosion and short circuits.

[0070] The cover 100 is, for example, a tape attached to the external FPC 30 or a coating layer included in the external FPC 30. After the inspection by the inspection equipment 90 is completed, the cover 100 covers the pads 45, 46, 47, and 48.

[0071] Generally, organic compounds are more hygroscopic than metals. Therefore, for example, in a high-humidity environment, moisture may condense in the form of a film on the surface of the organic compound layer 31. Such moisture may corrode the exposed pads 45, 46, 47, and 48. For example, the following creep corrosion may occur on the pads 45, 46, 47, and 48.

[0072] As described above, in the pads 45, 46, 47, and 48 of this embodiment, the gold plating 52 covers the metal layer 51. However, the gold plating 52 has defects (pinholes). Furthermore, copper, which is the material of the metal layer 51, has a stronger tendency to ionize than gold, which is the material of the gold plating 52. Therefore, the metal of the metal layer 51 may corrode and ionize due to an anodic reaction.

[0073] The metal of the ionized metal layer 51 advances to the outside, for example, through pinholes in the gold plating 52. The ionized metal advances along the surface of the external FPC 30 to around the pads 45, 46, 47, and 48. If the metal of the ionized metal layer 51 connects between the pads 45 and 46, the pads 45 and 46 may be short-circuited.

[0074] 5, the opening 65 and the hole 71 increase the creepage distance DC between the pads 45 and 46. In this embodiment, the creepage distance DC is the sum of twice the depth of the opening 65 in the Z direction, the difference between the length of the hole 71 and the length of the opening 65 in the Y direction, twice the depth of the hole 71 in the Z direction, and the length of the hole 71 in the Y direction. Note that the creepage distance DC is not limited to this example.

[0075] In this embodiment, the creepage distance DC is longer than the clearance CL between the pads 45 and 46. The clearance CL is approximately equal to the creepage distance between the pads 45 and 46 when the opening 65 and the hole 71 are not provided. In this embodiment, the creepage distance DC is more than twice the clearance CL. For example, the creepage distance DC is 150 μm or more longer than the clearance CL.

[0076] The opening 65 and the hole 71 similarly increase the creepage distance between the pad 45 and the wiring 42. Note that the wiring 42 is covered with the cover layer 33 and is therefore less susceptible to corrosion than the pads 45, 46, 47, and 48. Furthermore, the opening 66 and the hole 72 similarly increase the creepage distance between the pads 47 and 48.

[0077] Because the creepage distance DC is longer than the clearance distance CL, even if creep corrosion occurs in the pads 45, 46, 47, and 48, it takes a longer time for the metal of the ionized metal layer 51 to connect between the pads 45 and 46. Therefore, in the HDD 10, the time until a short circuit failure occurs in the pads 45, 46, 47, and 48 due to creep corrosion can be extended, thereby extending the product life. Note that when the cover 100 covers the pads 45, 46, 47, and 48, the pads 45, 46, 47, and 48 are less susceptible to corrosion.

[0078] Because the recesses 77 and 78 are recessed from the edge 68a of the opening 65, the ionized metal is less likely to travel beyond the end of the edge 68a in the −Z direction. In other words, the recesses 77 and 78 prevent the corroded metal from traveling between the pads 45 and 46.

[0079] Providing the openings 65 and 66 also means removing part of the highly hygroscopic organic compound layer 31 from the vicinity of the pads 45, 46, 47, and 48. This makes it difficult for moisture to condense near the pads 45, 46, 47, and 48, making the pads 45, 46, 47, and 48 less susceptible to corrosion.

[0080] The insulating coating 82 of the base 21 forms the inner surfaces of the holes 71 and 72. Therefore, even if ionized metal comes into contact with the inner surfaces of the holes 71 and 72, the coating 82 can prevent a short circuit between the base 21 and the pads 45, 46, 47, and 48.

[0081] In the HDD 10 according to the first embodiment described above, the external FPC 30 includes an organic compound layer 31, wirings 41 and 42, and pads 45 and 46. The lower surface 36a of the organic compound layer 31 is attached to the bottom wall 25. The wirings 41 and 42 are provided on the upper surface 35b of the organic compound layer 31. The pad 45 is connected to the wiring 41. The pad 46 is connected to the wiring 42 and is spaced apart from the pad 45. The external FPC 30 includes an opening 65 that penetrates the organic compound layer 31 and opens to the lower surface 36a and the upper surface 35b between the pads 45 and 46. This allows the HDD 10 according to this embodiment to have a longer creepage distance DC between the pads 45 and 46 than when the external FPC 30 does not include the opening 65.

[0082] Generally, for example, when the external FPC 30 is in a high-humidity environment, moisture condenses in the organic compound layer 31, which can cause creep corrosion of the metal of the pads 45 and 46. That is, the corroded metal ionizes and progresses along the surface of the organic compound layer 31. If the pads 45 and 46 are electrically connected by the corroded metal, a short circuit may occur between the pads 45 and 46.

[0083] In this embodiment, the creepage distance DC between the pads 45, 46 can be set long. Therefore, even if creep corrosion occurs in the pads 45, 46, the HDD 10 of this embodiment can lengthen the period until the pads 45, 46 are short-circuited by corroded metal, thereby extending the product life.

[0084] The external FPC 30 has a cover layer 33 that covers the top surface 35b and the wiring 41, 42. The cover layer 33 is provided with an exposure hole 61 that exposes the pads 45, 46 and the opening 65 to the outside of the external FPC 30. That is, the pads 45, 46 and the opening 65 are provided in an area exposed by a single exposure hole 61. In this area, the spatial distance CL between the pads 45, 46 may be short. However, the HDD 10 of this embodiment can increase the creepage distance DC between the pads 45, 46. Therefore, even if creep corrosion occurs in the pads 45, 46, the HDD 10 of this embodiment can increase the period until the pads 45, 46 are shorted by corroded metal, thereby extending the product life.

[0085] Pad 45 extends in the +X and −X directions along top surface 35b and has an edge 45a facing pad 46. Pad 46 extends in the +X and −X directions and has an edge 46a facing edge 45a. Opening 65 is located between the entire edge 45a and edge 46a. This prevents the HDD 10 of this embodiment from forming a portion between edges 45a, 46a where there is no opening 65 and the creepage distance DC is short, thereby lengthening the period until a short circuit occurs between pads 45, 46.

[0086] A hole 71 communicating with the opening 65 is provided in the bottom wall 25. This allows the creepage distance DC between the pads 45, 46 to be set even longer. Therefore, in the HDD 10 of this embodiment, the period until a short circuit occurs between the pads 45, 46 can be extended.

[0087] The pad 46 is spaced from the pad 45 in the Y direction along the top surface 35b. In the Y direction, the length (width) of the hole 71 is longer than the length (width) of the opening 65. Therefore, a portion of the hole 71 (recesses 77, 78) is recessed in the Y direction from the edge 68a of the opening 65. The creepage distance DC between the pads 45, 46 is equal to or greater than twice the depth of the opening 65, the difference between the length of the hole 71 and the length of the opening 65 in the Y direction, twice the depth of the hole 71, and the length of the hole 71 in the Y direction. Therefore, in the HDD 10 of this embodiment, the creepage distance DC between the pads 45, 46 can be further increased, and the period until a short circuit occurs between the pads 45, 46 can be extended.

[0088] The organic compound layer 31 has an adhesive layer 36 and a base layer 35. The adhesive layer 36 has a lower surface 36a of the organic compound layer 31. The base layer 35 has an upper surface 35b of the organic compound layer 31. In the Z direction perpendicular to the lower surface 36a, the length (depth) of the hole 71 is longer than the length (thickness) of the adhesive layer 36. This prevents the adhesive layer 36 from reaching the bottom of the hole 71, and more reliably recesses part of the hole 71 (recesses 77, 78) from the edge 68a of the opening 65 in the Y direction. Therefore, in the HDD 10 of this embodiment, the creepage distance DC between the pads 45, 46 can be further increased, and the period until a short circuit occurs between the pads 45, 46 can be extended.

[0089] The protrusion 79 protrudes from the bottom wall 25 through the opening 65. By inserting the protrusion 79 into the opening 65, for example, the external FPC 30 is guided to a predetermined position relative to the bottom wall 25. That is, the opening 65 is used to increase the creepage distance DC between the pads 45, 46 and can also be used to position the external FPC 30. Furthermore, the protrusion 79 is spaced apart from the edges 45a, 46a in the −X direction. Therefore, the protrusion 79 can be prevented from interfering with the compression connector 91 that contacts the pads 45, 46.

[0090] Each of the pads 45, 46 includes a metal layer 51 and a gold plating 52. The metal layer 51 is disposed on the upper surface 35b. The gold plating 52 covers the metal layer 51. The metal layer 51 includes at least one of copper and nickel. Generally, copper and nickel ionize more easily than gold. Furthermore, pinholes may exist in the gold plating 52. As a result, the metal layer 51 ionizes preferentially over gold, and ions penetrate through the pinholes to the outside of the gold plating 52. In other words, the pads 45, 46, which include the metal layer 51 and the gold plating 52, may be susceptible to creep corrosion. However, the HDD 10 of this embodiment can set a long creepage distance DC between the pads 45, 46, thereby lengthening the time until a short circuit occurs between the pads 45, 46.

[0091] The opening 65 is also located between the pad 45 and the wiring 42. This allows the creepage distance between the pad 45 and the wiring 42 to be set long. Therefore, even if creep corrosion occurs in the pad 45, the HDD 10 of this embodiment can lengthen the period until a short circuit occurs between the pad 45 and the wiring 42 due to corroded metal.

[0092] The cover 100, which is a tape, is attached to the external FPC 30 so as to cover at least one of the pads 45, 46. This protects at least one of the pads 45, 46 from, for example, a high-humidity environment and corrosive gases. Therefore, the HDD 10 of this embodiment can prevent creep corrosion from occurring in at least one of the pads 45, 46.

[0093] The cover 100 may be a coating layer that is included in the external FPC 30 and covers at least one of the pads 45, 46. In this case, at least one of the pads 45, 46 is protected from, for example, a high-humidity environment and corrosive gases. Therefore, the HDD 10 of this embodiment can suppress creep corrosion of at least one of the pads 45, 46.

[0094] The spindle motor 13 is electrically connected to the wiring 41, 42 and is supplied with power through the wiring 41, 42. That is, the pads 45, 46 are connected to the wiring 41, 42 for supplying power to the spindle motor 13. The HDD 10 of this embodiment can extend the product life by lengthening the period until the pads 45, 46 are short-circuited.

[0095] Fig. 7 is an exemplary plan view showing a portion of an external FPC 30 according to a first modified example of the first embodiment. As shown in Fig. 7, the external FPC 30 may have pads 115, 116, 117, and 118 provided at ends of wires 111, 112, 113, and 114. The wires 111, 112, 113, and 114 and the pads 115, 116, 117, and 118 are substantially the same as the wires 41, 42, 43, and 44 and the pads 45, 46, 47, and 48, except that the pads 115, 116, 117, and 118 are provided at ends of the wires 111, 112, 113, and 114. That is, the pads 45, 46, 47, 48, 115, 116, 117, and 118 may be provided in any part of the wirings 41, 42, 43, 44, 111, 112, 113, and 114.

[0096] Fig. 8 is an exemplary plan view showing a portion of an external FPC 30 according to a second modified example of the first embodiment. As shown in Fig. 8, the external FPC 30 has wirings 121, 122, and 123 and pads 125, 126, and 127, and may be provided with an exposure hole 131 and openings 135 and 136. The wirings 121, 122, and 123, the pads 125, 126, and 127, the exposure hole 131, and the openings 135 and 136 are substantially the same as the wirings 41, 42, and 43, the pads 45, 46, and 47, the exposure hole 61, and the opening 65, except for the points described below.

[0097] The three pads 125, 126, and 127 are arranged in the X direction with a gap therebetween. The pad 126 is located between the pads 125 and 127. The opening 135 is located between the pads 125 and 126. The opening 136 is located between the pads 126 and 127. The openings 135 and 136 communicate with holes 141 and 142 provided in the bottom wall 25, respectively. The holes 141 and 142 are substantially equal to the hole 71.

[0098] The exposure hole 131 exposes the three pads 125, 126, and 127 and the two openings 135 and 136 to the outside of the external FPC 30. That is, the exposure holes 61 and 131 provided in the cover layer 33 may expose three or more pads 125, 126, and 127 to the outside of the external FPC 30.

[0099] (Second embodiment) The second embodiment will be described below with reference to Figures 9 and 10. In the following description of the embodiment, components having the same functions as components already described are given the same reference numerals as the components already described, and further description may be omitted. Furthermore, multiple components given the same reference numerals do not necessarily have all the same functions and properties, and may have different functions and properties according to each embodiment.

[0100] Fig. 9 is an exemplary plan view showing a portion of an external FPC 30 according to the second embodiment. Fig. 10 is an exemplary cross-sectional view showing a portion of an HDD 10 according to the second embodiment along line F10-F10 in Fig. 9. As shown in Fig. 9, the bottom wall 25 according to the second embodiment has protrusions 201 and 202 instead of the holes 71 and 72 and the protrusion 79. The protrusion 201 is an example of a second protrusion.

[0101] 10 , the protrusions 201 and 202 protrude substantially in the +Z direction from the outer surface 25a of the bottom wall 25. The protrusion 201 is inserted into an opening 65 of the organic compound layer 31. The protrusion 202 is inserted into an opening 66 of the organic compound layer 31.

[0102] In the Z direction, the length of each of the protrusions 201 and 202 is longer than the length (thickness) of the organic compound layer 31. Therefore, the protrusion 201 passes from the bottom wall 25 through the opening 65 and protrudes beyond the upper surface 35b. Furthermore, the protrusion 202 passes from the bottom wall 25 through the opening 66 and protrudes beyond the upper surface 35b. In the Z direction, the length of the protrusion 201 is at least twice the length (thickness) of the organic compound layer 31. The length of the protrusion 201 is, for example, approximately 100 μm. Note that the dimensions of the protrusion 201 are not limited to this example.

[0103] 9, the protrusion 201 is formed in a substantially L-shape and has two portions 205 and 206. One portion 205 is located between the pads 45 and 46. In this embodiment, the portion 205 is located between the entire edge 45a of the pad 45 and at least a part of the edge 46a of the pad 46, and extends in the X direction. The other portion 206 is located between at least a part of the edge 45b of the pad 45 and a part of the wiring 42, and extends in the Y direction. The protrusion 202 is located between the edge 47a of the pad 47 and the edge 48a of the pad 48.

[0104] The insulating coating 82 of the base 21 forms the outer surfaces of the protrusions 201 and 202. Therefore, even if the protrusions 201 and 202 come into contact with the pads 45, 46, 47, and 48, the coating 82 can prevent short circuits between the base 21 and the pads 45, 46, 47, and 48.

[0105] In the HDD 10 of the second embodiment described above, the protrusion 201 passes through the opening 65 from the bottom wall 25 and protrudes beyond the top surface 35b. The protrusion 201 is located between the pads 45 and 46. This allows the creepage distance DC between the pads 45 and 46 to be set even longer. Furthermore, by protruding beyond the top surface 35b, the protrusion 201 prevents the progression of corroded metal between the pads 45 and 46. Therefore, the HDD 10 of this embodiment can lengthen the period until a short circuit occurs between the pads 45 and 46. Furthermore, the protrusion 201 can, for example, position the external FPC 30 relative to the bottom wall 25 during assembly of the HDD 10.

[0106] The protrusion 201 is located between the entire edge 45a and the edge 46a. This prevents the HDD 10 of this embodiment from forming a portion between the edges 45a, 46a where the protrusion 201 is absent and the creepage distance DC is short, thereby lengthening the period until a short circuit occurs between the pads 45, 46.

[0107] In the above description, "inhibit (or be inhibited)" is defined as, for example, preventing an event, action, or effect from occurring or reducing the magnitude of an event, action, or effect.

[0108] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. The contents of the claims as originally filed are as follows: [1] The wall and a substrate having an organic compound layer, a first surface of the organic compound layer attached to the wall, a second surface of the organic compound layer located on the opposite side to the first surface, a first wiring provided on the second surface, a second wiring provided on the second surface, a first pad connected to the first wiring, and a second pad connected to the second wiring and spaced apart from the first pad, wherein an opening is provided through the organic compound layer and opens to the first surface and the second surface between the first pad and the second pad; An electronic device comprising: [2] the substrate further has a cover layer that covers the second surface, the first wiring, and the second wiring; the cover layer is provided with an exposure hole that exposes the first pad, the second pad, and the opening to the outside of the substrate; [1] Electronic devices. [3] the first pad extends in a first direction along the second surface and has a first edge facing the second pad; the second pad extends in the first direction and has a second edge facing the first edge; The opening is located between the entire first edge and the second edge. [1] Electronic devices. [4] The wall is provided with a hole communicating with the opening. [3] Electronic devices. [5] the second pad is spaced from the first pad in a second direction along the second surface; In the second direction, the length of the hole is longer than the length of the opening. [4] Electronic devices. [6] the organic compound layer has an adhesive layer having the first surface and an insulator layer having the second surface, In a third direction perpendicular to the first surface, the length of the hole is longer than the length of the adhesive layer. [5] Electronic devices. [7] a first projection projecting from the wall through the opening; Further comprising: the first protrusion is spaced apart from the first edge and the second edge in the first direction; [4] Electronic devices. [8] a second protrusion extending from the wall through the opening and beyond the second surface and positioned between the first pad and the second pad; [3] The electronic device further comprises: [9] The second protrusion is located between the entire area of ​​the first edge and the second edge. [8] Electronic devices.

[10] the first pad has a first metal layer provided on the second surface and connected to the first wiring, and a first gold plating covering the first metal layer; the second pad has a second metal layer provided on the second surface and connected to the second wiring, and a second gold plating covering the second metal layer; each of the first metal layer and the second metal layer includes at least one of copper and nickel; Any one of the electronic devices listed in [1] to [9].

[11] The opening is also located between the first pad and the second wiring. Any one of the electronic devices listed in [1] to [9].

[12] a tape attached to the substrate so as to cover at least one of the first pad and the second pad; An electronic device according to any one of [1] to [9], further comprising:

[13] the substrate further includes a coating layer covering at least one of the first pad and the second pad; Any one of the electronic devices listed in [1] to [9].

[14] an electrical component electrically connected to the first wiring and the second wiring and supplied with power through the first wiring and the second wiring; An electronic device according to any one of [1] to [9], further comprising:

[15] The substrate is a flexible printed wiring board. Any one of the electronic devices listed in [1] to [9].

[16] a housing having the wall; An electronic device according to any one of [1] to [9], further comprising:

[17] the opening is adjacent to the first pad and the second pad; Any one of the electronic devices listed in [1] to [9]. [Explanation of symbols]

[0109] 10...Hard disk drive (HDD), 11...Housing, 13...Spindle motor, 25...Bottom wall, 30...External flexible printed circuit board (FPC), 31...Organic compound layer, 33...Cover layer, 35...Base layer, 35b...Top surface, 36...Adhesive layer, 36a...Bottom surface, 41, 42, 111, 112, 121, 122...Wiring, 45, 46, 115, 116, 125, 126...Pads, 45a, 46a...Edge, 51...Metal layer, 52...Gold plating, 61, 131...Exposure holes, 65, 135...Openings, 71, 141...Holes, 79, 201...Protrusions, 100...Cover

Claims

1. The wall and a substrate having an organic compound layer, a first surface of the organic compound layer attached to the wall, a second surface of the organic compound layer located on the opposite side to the first surface, a first wiring provided on the second surface, a second wiring provided on the second surface, a first pad connected to the first wiring, and a second pad connected to the second wiring and spaced apart from the first pad, wherein an opening is provided through the organic compound layer and opens to the first surface and the second surface between the first pad and the second pad; a first projection projecting from the wall through the opening; Equipped with the first pad extends in a first direction along the second surface and has a first edge facing the second pad; the second pad extends in the first direction and has a second edge facing the first edge; the opening is located between the entire first edge and the second edge; a hole in the wall that communicates with the opening; the first protrusion is spaced apart from the first edge and the second edge in the first direction; electronic equipment.

2. the substrate further has a cover layer that covers the second surface, the first wiring, and the second wiring; the cover layer is provided with an exposure hole that exposes the first pad, the second pad, and the opening to the outside of the substrate; The electronic device of claim 1.

3. the second pad is spaced apart from the first pad in a second direction along the second surface; In the second direction, the length of the hole is longer than the length of the opening. The electronic device of claim 1.

4. the organic compound layer has an adhesive layer having the first surface and an insulator layer having the second surface, a length of the hole in a third direction perpendicular to the first surface, the length of the hole being longer than a length of the adhesive layer; The electronic device of claim 3.

5. the first pad has a first metal layer provided on the second surface and connected to the first wiring, and a first gold plating covering the first metal layer; the second pad has a second metal layer provided on the second surface and connected to the second wiring, and a second gold plating covering the second metal layer; each of the first metal layer and the second metal layer includes at least one of copper and nickel; 5. An electronic device according to claim 1.

6. The opening is also located between the first pad and the second wiring.

5. An electronic device according to claim 1.

7. a tape attached to the substrate so as to cover at least one of the first pad and the second pad; 5. The electronic device according to claim 1, further comprising:

8. the substrate further includes a coating layer covering at least one of the first pad and the second pad; 5. An electronic device according to claim 1.

9. an electrical component electrically connected to the first wiring and the second wiring and supplied with power through the first wiring and the second wiring; 5. The electronic device according to claim 1, further comprising:

10. The substrate is a flexible printed wiring board.

5. An electronic device according to claim 1.

11. a housing having the wall; 5. The electronic device according to claim 1, further comprising:

12. the opening is adjacent to the first pad and the second pad; 5. An electronic device according to claim 1.

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