Printed Circuit Boards and Circuit Boards

Abstract

To provide a print circuit board capable of suppressing the increase in size and warping of a circuit board.SOLUTION: A wiring 40 of a print circuit board 20 includes: a signal wiring 41; and a potential fixed wiring that is fixed to a predetermined potential and arranged to face the signal wiring 41 via an insulating base material 30. A ground wiring 42 as the potential fixed wiring has a protrusion 422 on the opposite side 42a to the signal wiring 41. The protrusion 422 is arranged to overlap with at least one of the signal wiring 41. The signal wiring 41 includes a counter wiring 411 that faces the protrusion 422 via the insulating base material 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] TECHNICAL FIELD The disclosure herein relates to printed circuit boards and circuit boards. [Background technology]

[0002] A printed circuit board is disclosed in Patent Document 1. The contents of the prior art documents are incorporated by reference as explanations of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-100699 Summary of the Invention [Problem to be solved by the invention]

[0004] Increasing the thickness of a printed circuit board is effective in suppressing warpage caused by reflow or other processes. Increasing the thickness of the insulating layer between multiple wiring layers increases the opposing distance between the signal wiring and the ground wiring, reducing the coupling capacitance. This increases the impedance of the signal wiring. In response to this, increasing the width and thickness of the signal wiring can be considered to reduce the impedance of the signal wiring and achieve impedance matching with electronic components. Increasing the thickness of the signal wiring increases the wiring width and spacing in patterning. Therefore, increasing the width and thickness increases the physical size of the printed circuit board. Further improvements are required for printed circuit boards and circuit boards in terms of the above and other aspects not mentioned.

[0005] One disclosed object is to provide a printed circuit board and a circuit board that can suppress warping while suppressing an increase in size. [Means for solving the problem]

[0006] The printed circuit board disclosed herein One of teeth, an insulating substrate (30); Wiring (40) arranged in multiple layers on an insulating substrate; Equipped with the wiring includes a signal wiring (41) and potential fixed wiring (42, 43) fixed to a predetermined potential and arranged to face the signal wiring across the insulating substrate in the plate thickness direction of the insulating substrate; At least one of the potential fixing wirings has a base (421, 431) and a protruding portion (422, 432) protruding in a plate thickness direction from a surface of the base facing the signal wiring, the protruding portion is arranged so as to overlap at least one of the signal wirings in a plan view in the plate thickness direction; The signal wiring includes an opposing wiring (411) that faces the protruding portion via an insulating substrate. fruit, the protruding portion is provided in common to a plurality of opposing wirings so as to overlap with the plurality of opposing wirings arranged in the same layer; Printed circuit board. The other printed circuit board is an insulating substrate (30); Wiring (40) arranged in multiple layers on an insulating substrate; Equipped with the wiring includes a signal wiring (41) and potential fixed wiring (42, 43) fixed to a predetermined potential and arranged to face the signal wiring across the insulating substrate in the plate thickness direction of the insulating substrate; the potential fixing wiring has a base (421, 431), and at least one of the potential fixing wirings has a protruding portion (422, 432) protruding in a plate thickness direction from a surface of the base facing the signal wiring; the protruding portion is arranged so as to overlap at least one of the signal wirings in a plan view in the plate thickness direction; the signal wiring includes an opposing wiring (411) that faces the protruding portion via an insulating substrate; the potential fixed wiring includes a first potential fixed wiring and a second potential fixed wiring arranged in different layers so as to sandwich the opposing wiring; a protrusion is provided on at least one of the first potential fixing wiring and the second potential fixing wiring; In the thickness direction of the plate, a base of the first potential fixed wiring is disposed at a position closer to the opposing wiring than a base of the second potential fixed wiring; The first potential fixing wiring has a protrusion. . The other printed circuit board is an insulating substrate (30); Wiring (40) arranged in multiple layers on an insulating substrate; Equipped with the wiring includes a signal wiring (41) and potential fixed wiring (42, 43) fixed to a predetermined potential and arranged to face the signal wiring across the insulating substrate in the plate thickness direction of the insulating substrate; At least one of the potential fixing wirings has a base (421, 431) and a protruding portion (422, 432) protruding in a plate thickness direction from a surface of the base facing the signal wiring, the protruding portion is arranged so as to overlap at least one of the signal wirings in a plan view in the plate thickness direction; the signal wiring includes an opposing wiring (411) that faces the protruding portion via an insulating substrate; The potential fixed wiring having a protruding portion has an overlapping region (423, 433) with the opposing wiring and a peripheral region (424, 434) connected to the overlapping region, In the peripheral region, the length from the inner edge, which is the boundary with the overlap region, to the outer edge is equal to or greater than the width of the opposing wiring. .

[0007] The circuit board disclosed herein comprises: a printed circuit board (20) having an insulating substrate (30) and wiring (40) arranged in multiple layers on the insulating substrate; an electronic component (50) mounted on a printed circuit board; Equipped with the wiring includes a signal wiring (41) electrically connected to the electronic component, and potential fixed wiring (42, 43) fixed to a predetermined potential and arranged to face the signal wiring via an insulating base material in the thickness direction of the printed circuit board; At least one of the potential fixing wirings has a base (421, 431) and a protruding portion (422, 432) protruding in a plate thickness direction from a surface of the base facing the signal wiring, the protruding portion is arranged so as to overlap at least one of the signal wirings in a plan view in the plate thickness direction; The signal wiring includes an opposing wiring (411) that faces the protruding portion via an insulating substrate. fruit, The protruding portion is provided in common to a plurality of opposing wirings arranged in the same layer so as to overlap with the opposing wirings.

[0008] In the disclosed printed circuit board and circuit board, a protrusion is provided on the potential fixing wiring. This makes the potential fixing wiring thick where the protrusion is provided. Meanwhile, in the portion of the insulating substrate (insulating layer) arranged between adjacent wiring, the portion in contact with the base is thick. In other words, when viewed in a plan view in the board thickness direction, the potential fixing wiring is thick where the protrusion is provided, and the insulating substrate (insulating layer) is thick where no protrusion is provided. This makes it possible to suppress warping.

[0009] Furthermore, the protrusion is provided at a position overlapping the opposing wiring on the opposing surface of the potential fixed wiring. This allows the insulating substrate (insulating layer) between the protrusion and the opposing wiring to be thin, increasing the coupling capacitance between the opposing wiring and the potential fixed wiring and reducing the impedance of the opposing wiring. Since the impedance can be adjusted without increasing the width or thickness of the signal wiring, the increase in physical size can be suppressed. As a result, it is possible to provide a printed circuit board and a circuit board that can suppress warping while also suppressing an increase in physical size.

[0010] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify correspondences with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view showing a circuit board according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a plan view showing the positional relationship between signal wiring, protrusions, and ground wiring. [Figure 4] FIG. 10 is a cross-sectional view showing a modified example. [Figure 5] FIG. 10 is a cross-sectional view showing a printed circuit board in a circuit board according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing a printed circuit board in a circuit board according to a third embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments. When only a portion of a configuration is described in each embodiment, the configuration of the other previously described embodiment may be applied to the other parts of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0013] (First embodiment) First, the general configuration of the printed circuit board and the circuit board will be described.

[0014] <Printed circuit boards and circuit boards> FIG. 1 is a plan view showing an example of a circuit board. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 2 shows a printed circuit board, which is one of the circuit boards. Hereinafter, the thickness direction of the printed circuit board will be referred to as the Z direction. Furthermore, a direction perpendicular to the Z direction will be referred to as the X direction, and a direction perpendicular to both the Z direction and the X direction will be referred to as the Y direction. Unless otherwise specified, a shape viewed from the Z direction, in other words, a shape along the XY plane defined by the X direction and the Y direction, will be referred to as a planar shape. The planar view from the Z direction may sometimes be simply referred to as a planar view.

[0015] 1 and 2, the circuit board 10 includes a printed circuit board 20, an electronic component 50, and a connector 60. The circuit configured on the circuit board 10 can be electrically connected to an external device via the connector 60.

[0016] The printed circuit board 20 may also be referred to as a board, a wiring board, a printed wiring board, etc. The printed circuit board 20 has one surface 20a and a back surface 20b that is the surface opposite to the one surface 20a in the board thickness direction (Z direction). The planar shape of the printed circuit board 20 is not particularly limited. As an example, the printed circuit board 20 has a substantially rectangular planar shape.

[0017] The printed circuit board 20 comprises an insulating substrate 30 and circuit elements arranged on the insulating substrate 30. The circuit elements include wiring 40. The insulating substrate 30 is a substrate that supports (holds) the circuit elements. The insulating substrate 30 is formed using an electrically insulating material such as resin. The insulating substrate 30 may be made of, for example, a material containing only resin, or a material combining glass cloth, nonwoven fabric, or the like with resin. The insulating substrate 30 is formed by laminating multiple insulating layers 31. The insulating layers 31 are sometimes called insulating sheets.

[0018] There is no particular limitation on the number of insulating layers 31. As an example, the insulating base material 30 of this embodiment is configured by stacking five insulating layers 31. Of the five layers, the middle insulating layer 31 is thicker than the other insulating layers 31.

[0019] The circuit elements including the wiring 40, together with the electronic components 50 mounted on the printed circuit board 20, provide a circuit. The wiring 40 may be referred to as a wiring pattern, a conductor pattern, a wiring layer, a conductor layer, etc. The wiring 40 is arranged in multiple layers on the insulating substrate 30 in the Z direction. In other words, the printed circuit board 20 is a multi-layer board. The number of layers of the wiring 40 is not particularly limited. As an example, the wiring 40 is arranged in six layers. In the following, of the wiring 40 arranged in multiple layers, the wiring 40 provided on the surface layer on the one surface 20a side is referred to as the first layer.

[0020] The wiring 40 is formed by patterning a metal foil, for example. An example of the metal foil is copper foil. The wiring 40 includes a surface conductor disposed on the surface of the insulating base material 30 and an inner layer conductor disposed inside the insulating base material 30.

[0021] A configuration in which wiring 40 is arranged in multiple layers on the insulating substrate 30 can be realized by using multiple insulating layers 31, each having wiring 40 arranged on at least one surface. The printed circuit board 20 may be configured by stacking only insulating layers 31 having wiring 40 arranged thereon, or insulating layers 31 having no wiring 40 arranged on both surfaces may be included as part of the multiple insulating layers 31 to be stacked. For example, insulating layers 31 having no wiring 40 arranged on both surfaces may be placed between insulating layers 31 having wiring 40 arranged thereon. The timing of patterning the wiring 40 can be selected appropriately depending on the manufacturing method. Individual insulating layers 31 may be patterned before being stacked, or multiple insulating layers 31 may be patterned after being stacked.

[0022] The wiring 40 includes a signal wiring 41, a ground wiring 42, and a power wiring 43. The signal wiring 41 may be referred to as a signal line, a signal pattern, or the like. The signal wiring 41 is electrically connected to the electronic component 50. A plurality of signal wirings 41 are arranged in the insulating substrate 30. The arrangement and number of layers of the signal wirings 41 are not particularly limited. As an example, the signal wirings 41 are arranged in multiple layers in the insulating substrate 30.

[0023] The ground wiring 42 and the power supply wiring 43 are fixed to a predetermined potential via the connector 60. The ground wiring 42 and the power supply wiring 43 correspond to potential fixed wiring. Hereinafter, they may be referred to as potential fixed wirings 42, 43. The ground wiring 42 provides a ground potential in the printed circuit board 20 (circuit board 10). The power supply wiring 43 provides a power supply potential in the printed circuit board 20. The ground wiring 42 may be referred to as a ground layer, a ground pattern, etc. The power supply wiring 43 may be referred to as a power supply layer, a power supply pattern, etc.

[0024] The arrangement of the ground wiring 42 and the power supply wiring 43 is not particularly limited. The number of layers of the ground wiring 42 and the number of layers of the power supply wiring 43 are also not particularly limited. As an example, the ground wiring 42 is arranged in multiple layers. At least one of the ground wiring 42 and the power supply wiring 43 is arranged so as to face at least one of the signal wirings 41 with the insulating base material 30 (insulating layer 31) interposed therebetween.

[0025] The printed circuit board 20 includes via conductors (not shown) as circuit elements. The via conductors electrically connect the wiring 40 arranged on different layers. The via conductors are sometimes referred to as connection vias, interlayer connections, etc. The via conductors are formed by arranging a conductor such as plating inside a via hole. The printed circuit board 20 may also include through holes (not shown) as circuit elements. The through holes are formed by plating the wall surfaces of holes that penetrate the printed circuit board 20. The through holes are sometimes referred to as through-hole plating. Terminals of the electronic components 50 are inserted into the through holes. The conductors on the wall surfaces of the through holes and the terminals are connected by a bonding material such as solder.

[0026] The printed circuit board 20 includes a resist (not shown). The resist protects the circuit elements of the printed circuit board 20. The resist is sometimes called a solder resist, a protective film, or the like. The resist is disposed on one surface 20a and / or the back surface 20b of the printed circuit board 20. The resist covers the circuit elements disposed on the surface layer, except for lands (not shown).

[0027] The electronic components 50 are mounted on the printed circuit board 20. A plurality of electronic components 50 are mounted on the printed circuit board 20. The electronic components 50 are generally arranged on one surface 20a and / or the back surface 20b of the printed circuit board 20. At least a portion of the electronic components 50 may be embedded in the insulating substrate 30. The electronic components 50 form a circuit together with circuit elements such as the wiring 40 as described above. The circuit board 10 includes the electronic components 50 to provide a predetermined function.

[0028] <Protrusions and opposing wiring> Next, the protruding portion and the opposing wiring will be described with reference to FIGS.

[0029] At least one of the potential fixing wirings 42, 43, which are arranged so as to face the signal wiring 41 across the insulating substrate 30, has a base and a protrusion that protrudes in the Z direction from the surface of the base facing the signal wiring 41. That is, it has a thin-walled portion that is only the base and a thick-walled portion that is the base plus the protrusion. The potential fixing wirings 42, 43 with protrusions can be realized, for example, by using a profiled metal foil (profile material) with partially different thicknesses. In this case, the protrusions can be provided on both the surface that contacts the insulating layer 31 and its back surface. Alternatively, a flat metal foil may be plated. In this case, the protrusions can be provided on the back surface (exposed surface) of the surface that contacts the insulating layer 31.

[0030] 2, in this embodiment, the ground wiring 42 arranged in the second layer has a base 421 and a protruding portion 422. The power supply wiring 43 arranged in the fourth layer and the ground wiring 42 arranged in the fifth layer do not have the protruding portion 422. In other words, they only have the base 421. The protruding portion 422 protrudes in the Z direction from a surface 42a of the base 421 that faces the signal wiring 41 arranged in the third layer. In a plan view, the portion with only the base 421 is a thin portion, and the portion where the protruding portion 422 is provided is a thick portion.

[0031] The ground wiring 42 has a so-called solid pattern. The ground wiring 42 does not have openings like a mesh pattern, and is a flat plate with a larger area than the signal wiring 41. The solid-pattern ground wiring 42 is sometimes called a solid ground. The ground wiring 42 does not have a protrusion 422 on the back surface 42b opposite the opposing surface 42a.

[0032] The protruding portion 422 is arranged so as to overlap at least one of the signal wirings 41 arranged in the third layer in plan view. As an example, in FIG. 2, the signal wiring 41 arranged in the third layer is the opposing wiring 411. The opposing wiring 411 faces the protruding portion 422 via one insulating layer 31. The signal wirings 41 arranged in other layers, specifically the first and sixth layers, are signal wirings 412 separate from the opposing wiring 411. The signal wirings 412 are non-opposing wirings that do not face the protruding portion 422.

[0033] The opposing wiring 411 is the signal wiring 41 through which a signal with a frequency of 1 kHz or more flows. As an example, the opposing wiring 411 in this embodiment is the signal wiring 41 through which a signal with a frequency of 100 MHz or more flows. At least a part of the signal wiring 412 is the signal wiring 41 through which a signal with a lower frequency than the opposing wiring 411 flows. In other words, the opposing wiring 411 is a high-speed communication wiring, and at least a part of the signal wiring 412 is a wiring that transmits a signal slower than the opposing wiring 411.

[0034] The protrusion 422 has an overlapping region 423 and a peripheral region 424. The overlapping region 423 is a region that overlaps with the opposing wiring 411 in a plan view. The overlapping region 423 is a region directly above or directly below the opposing wiring 411. The peripheral region 424 is a region that is continuous with the overlapping region 423 and extends from the overlapping region 423 to its periphery. The peripheral region 424 is a non-overlapping region that does not overlap with the opposing wiring 411.

[0035] The protruding portion 422 is provided so as to overlap at least a part of the counter wiring 411 in a plan view. As an example, the protruding portion 422 in this embodiment is provided so as to enclose the counter wiring 411 provided in the third layer. In other words, the protruding portion 422 is provided so as to overlap with almost the entire area of ​​the counter wiring 411.

[0036] 3 shows an example of a plurality of signal wirings 41 arranged on the third layer. FIG. 3 shows the positional relationship between the signal wirings 41 including the counter wirings 411, the ground wirings 42, and the protrusions 422. For convenience, FIG. 3 illustrates the signal wirings 41, the ground wirings 42, and the protrusions 422 on the same plane. In FIG. 3, some of the plurality of signal wirings 41 arranged on the third layer are the counter wirings 411, and the rest are the signal wirings 412.

[0037] The protruding portions 422 are provided so as to individually enclose the opposing wiring 411 in a plan view. The protruding portions 422 are provided so as to overlap the opposing wiring 411 over their entire length. The opposing wiring 411 is a single-ended signal wiring 41. The opposing wiring 411 has a meander wiring portion that has a meander shape. The protruding portions 422 are provided so as to enclose the entire meander wiring portion.

[0038] The signal wiring 412 is a pair of differential wirings 412a and 412b. In the case of the differential wirings 412a and 412b, the impedance can be adjusted by the wiring spacing. For this reason, in the example shown in FIG. 3, the differential wirings 412a and 412b are not provided with protrusions 422.

[0039] In this embodiment, the overlapping region 423 substantially coincides with the opposing wiring 411 in a plan view. The peripheral region 424 is provided so as to surround the opposing wiring 411 (overlapping region 423) in a plan view. The length W2 of the peripheral region 424 from the inner end to the outer end, which is the boundary with the overlapping region 423, i.e., the width W2 of the peripheral region 424, is equal to or greater than the width W1 of the opposing wiring 411. The width of the opposing wiring 411 is the length in a direction perpendicular to the extension direction (longitudinal direction) of the opposing wiring 411.

[0040] <Summary of the First Embodiment> Increasing the thickness of a printed circuit board is an effective way to suppress warping of the printed circuit board caused by reflow or other processes. Increasing the thickness of the insulating layer between wiring on different layers increases the opposing distance between the signal wiring and the potential fixed wiring, reducing the coupling capacitance. This increases the impedance of the signal wiring. In response to this, increasing the width and thickness of the signal wiring can be considered to reduce the impedance of the signal wiring and achieve impedance matching with electronic components. However, thickening the signal wiring increases the wiring width and spacing in patterning. Therefore, increasing the width and thickness increases the physical size of the printed circuit board.

[0041] It is also possible to use a material with a high dielectric constant for the insulating substrate (insulating layer) to reduce the impedance of the signal wiring, suppressing increases in size and achieving impedance matching with electronic components, but this increases dielectric loss.

[0042] In this embodiment, the ground wiring 42 (potential fixing wiring) in the second layer, which faces the signal wiring 41 in the third layer across the insulating layer 31 (insulating base material 30), has a protrusion 422. The protrusion 422 is arranged so as to overlap at least one of the signal wirings 41 in a plan view. The signal wiring 41 includes an opposing wiring 411 which faces the protrusion 422 across the insulating layer 31.

[0043] The second-layer ground wiring 42 is thick in the area where the protrusion 422 is provided. Meanwhile, the insulating layer 31 interposed between the second-layer ground wiring 42 and the third-layer signal wiring 41 is thick in the area in contact with the base 421. In other words, the ground wiring 42 is thick in the area where the protrusion 422 is provided, and the insulating layer 31 is thick in the area where the protrusion 422 is not provided. This makes it possible to suppress warping of the printed circuit board 20 that occurs during reflow or the like. Suppressing warping can improve the reliability of solder joints between the printed circuit board 20 (wiring 40) and the electronic component 50, for example.

[0044] Furthermore, by providing the protrusion 422 at a position overlapping the counter wiring 411 on the opposing surface 42a of the ground wiring 42, the insulating layer 31 interposed between the protrusion 422 and the counter wiring 411 is thin. In other words, the opposing distance between the protrusion 422 (ground wiring 42) and the counter wiring 411 is short. This increases the coupling capacitance between the counter wiring 411 and the ground wiring 42, thereby reducing the impedance of the counter wiring 411. Since the impedance can be adjusted without increasing the width or thickness of the signal wiring 41, an increase in the physical size of the printed circuit board 20 can be suppressed. As described above, according to this embodiment, it is possible to suppress an increase in the physical size while suppressing warpage. Furthermore, since it is not necessary to use a material with a high dielectric constant for the insulating base material 30 (insulating layer 31), the above-mentioned effects can be achieved while reducing dielectric loss.

[0045] The protruding height of the protruding portion 422 is not particularly limited and can be set within a range that ensures electrical insulation between the protruding portion 422 and the opposing wiring 411. The higher the protruding height, that is, the shorter the opposing distance between the protruding portion 422 and the opposing wiring 411, the more effectively it is possible to reduce the impedance of the opposing wiring 411.

[0046] In this embodiment, the potential fixed wirings 42 and 43 are arranged in the second and fourth layers so as to sandwich the counter wiring 411 in the third layer in the Z direction. Without the protruding portion 422, the distance L1 between the ground wiring 42 (base 421) in the second layer and the counter wiring 411 is shorter than the distance L2 between the power supply wiring 43 in the fourth layer and the counter wiring 411. In this inter-layer distance relationship, the protruding portion 422 is provided on the ground wiring 42, which has a shorter distance, i.e., is closer to the counter wiring 411. This further shortens the opposing distance to the counter wiring 411, and increases the coupling capacitance between the counter wiring 411 and the ground wiring 42. This enhances the effect of reducing the impedance of the counter wiring 411. The ground wiring 42 corresponds to the first potential fixed wiring, and the power supply wiring 43 corresponds to the second potential fixed wiring.

[0047] The frequency of the signal flowing through the opposing wiring 411 is not particularly limited. In this embodiment, a signal with a frequency of 1 kHz or higher flows through the opposing wiring 411. At frequencies of 1 kHz or higher, impedance management, i.e., impedance matching, becomes important. Stricter management is required particularly at frequencies of 100 MHz or higher. According to this embodiment, the protrusion 422 is provided corresponding to the opposing wiring 411 through which a signal with a frequency of 1 kHz or higher flows, thereby making it possible to suppress loss due to impedance mismatch between the opposing wiring 411 and the electronic component 50.

[0048] The opposing wiring 411 may include only single-ended wiring or only differential wiring. The opposing wiring 411 may include both. In the case of differential wiring, the impedance can be adjusted by the wiring spacing. In the case of single-ended wiring, the impedance cannot be adjusted by the wiring spacing as in differential wiring. Therefore, if an attempt is made to suppress warping, an increase in physical size becomes a problem. In this embodiment, since the protrusion 422 is provided as described above, it is possible to suppress an increase in physical size while employing single-ended wiring as the opposing wiring 411.

[0049] The protrusion 422 may be disposed so as to overlap at least a portion of the entire length of the counter wiring 411. The impedance of the counter wiring 411 can also be adjusted by the size of the overlap with the protrusion 422, i.e., the area. In addition to the height of the protrusion 422, the number of parameters for adjusting the impedance increases, thereby improving the degree of freedom in design. For example, the protrusion 422 may be provided so as to overlap only a portion of the entire length of the counter wiring 411.

[0050] The radiated electric field of the counter wiring 411 has a predetermined spread. The electric field strength is high not only directly above or directly below the counter wiring 411 but also in the periphery thereof. In this embodiment, the protrusion 422 is provided not only directly above the counter wiring 411 but also in the periphery thereof. This increases the capacitive coupling, and can enhance the effect of reducing the impedance of the counter wiring 411. In particular, since the protrusion 422 is provided so as to satisfy the relationship W2≧W1, the effect of reducing the impedance of the counter wiring 411 can be further enhanced.

[0051] In this way, the impedance of the counter wiring 411 can be adjusted also by the width W2 of the peripheral region 424. In addition to the height of the protrusion 422, the number of parameters for adjusting the impedance increases, thereby improving the degree of freedom in design.

[0052] <Modification> The protrusion 422 is provided for the signal wiring 41 that requires impedance matching. As described above, some of the multiple signal wirings 41 arranged on a common layer may be used as counter wirings 411, and the remaining may be used as signal wirings 412. All of the multiple signal wirings 41 arranged on a common layer may be used as counter wirings 411. The presence or absence of the protrusion 422 makes it possible to select between the counter wirings 411 and the signal wirings 412. This improves the degree of freedom in designing the signal wirings 41.

[0053] Although an example has been shown in which the protrusion 422 is provided on the ground wiring 42 on the second layer and the signal wiring 41 on the third layer is used as the opposing wiring 411, this is not limiting. The potential fixing wiring on which the protrusion 422 is provided is not limited to the ground wiring 42. For example, instead of the ground wiring 42 on the second layer, a protrusion may be provided on the power supply wiring 43 on the fourth layer. For example, as shown in FIG. 4, the signal wiring 41 arranged on the first layer (surface layer) may be used as the opposing wiring 411. FIG. 4 corresponds to FIG. 2. In FIG. 4, the protrusion 422 is provided on the surface of the ground wiring 42 on the second layer facing the first layer. Alternatively, the signal wiring 41 arranged on the sixth layer, which is the surface layer, may be used as the opposing wiring 411, or the signal wiring 41 arranged on an inner layer other than the second layer may be used as the opposing wiring 411.

[0054] In a configuration in which the potential fixed wirings 42 and 43 are arranged to sandwich the counter wiring 411, the distance L2 between the power supply wiring 43 and the counter wiring 411 may be shorter than the distance L1 between the ground wiring 42 (base 421) and the counter wiring 411. In this configuration, a protrusion may be provided only on the power supply wiring 43. In this case, the power supply wiring 43 corresponds to the first potential fixed wiring, and the ground wiring 42 corresponds to the second potential fixed wiring.

[0055] The configuration of the peripheral region 424 is not limited to the above example. For example, the peripheral region 424 may be provided on only one side in the width direction. The width of the peripheral region 424 may be different on both sides.

[0056] (Second embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used.

[0057] 5 is a cross-sectional view showing the printed circuit board 20 in the circuit board 10 according to this embodiment. FIG. 5 corresponds to FIG.

[0058] As in the preceding embodiment, in this embodiment, potential fixing wirings 42 and 43 are arranged in the second and fourth layers so as to sandwich the opposing wiring 411 in the third layer in the Z direction. In addition, the ground wiring 42 in the second layer has a protruding portion 422. In this embodiment, the power supply wiring 43 in the fourth layer also has a base 431 and a protruding portion 432. The protruding portion 432 protrudes in the Z direction from a surface 43a of the base 431 that faces the signal wiring 41 arranged in the third layer. In a plan view, the portion of only the base 431 is a thin portion, and the portion where the protruding portion 432 is provided is a thick portion. The protruding portion 432 is not provided on the back surface 43b of the opposing surface 43a.

[0059] As in the previous embodiment, the distance L1 between the base 421 of the ground wiring 42 and the counter wiring 411 is shorter than the distance L2 between the base 431 of the power supply wiring 43 and the counter wiring 411. The height H1 of the protrusion 422 is shorter than the distance L1. The height H2 of the protrusion 432 is shorter than the distance L2. The heights H1 and H2 may be equal to each other or may be different values. For example, H1 > H2 or H2 > H1 may be satisfied.

[0060] Like the previous embodiment, the protrusion 422 has an overlapping region 423 and a peripheral region 424. The protrusion 432 also has an overlapping region 433 and a peripheral region 434. The overlapping region 433 is a region that overlaps with the opposing wiring 411 in a plan view. The overlapping region 433 is a region directly above or directly below the opposing wiring 411. The peripheral region 434 is a region that is continuous with the overlapping region 433 and extends from the overlapping region 433 to its periphery. The peripheral region 434 is a non-overlapping region that does not overlap with the opposing wiring 411.

[0061] The protrusion 432 is provided so as to overlap, in plan view, at least a part of the counter wiring 411. The other configurations are the same as those exemplified in the preceding embodiment.

[0062] <Summary of the second embodiment> In this embodiment, the power supply wiring 43 is also arranged to face the counter wiring 411 with the insulating layer 31 interposed therebetween. The power supply wiring 43 has a protrusion 432 provided to overlap the counter wiring 411 in a plan view. The counter wiring 411 faces the protrusion 432 of the power supply wiring 43. In other words, the potential fixing wirings 42 and 43 arranged to sandwich the counter wiring 411 are provided with protrusions 422 and 432, respectively. This makes it possible to further reduce the impedance of the counter wiring 411.

[0063] For example, if L1 is 200 μm, L2 is 400 μm, and the thickness of the wiring 40 in each layer is 35 μm, the wiring width of the opposing wiring 411 needs to be 195 μm to achieve an impedance of 50 ohms without providing the protrusions 422 and 432. By providing the protrusions 422 and 432 with heights H1 and H2 of 100 μm, the wiring width of the opposing wiring 411 can be reduced to 115 μm. In other words, the wiring area of ​​the opposing wiring 411 can be reduced by approximately 40%. This effectively prevents the wiring size from increasing. In the potential fixed wirings 42 and 43 having the protrusions 422 and 432, the thickness of the bases 421 and 431 is 35 μm.

[0064] The protrusions 422, 432 may be provided on at least one of the potential fixed wirings 42, 43 arranged to sandwich the counter wiring 411. Providing only one of the protrusions 422, 432 is less effective than a configuration in which both are provided, but it is possible to reduce the wiring width of the counter wiring 411 compared to a configuration in which the protrusions 422, 432 are not provided. The impedance of the counter wiring 411 changes depending on the number of potential fixed wirings 42, 43 having the protrusions 422, 432. In addition to the height of the protrusions 422, 432, the number of parameters for adjusting the impedance increases, thereby improving design freedom.

[0065] The potential fixing wirings arranged to sandwich the counter wiring 411 are not limited to the combination of the ground wiring 42 and the power supply wiring 43. For example, the counter wiring 411 may be arranged between the ground wirings 42, or the counter wiring 411 may be arranged between the power supply wirings 43.

[0066] (Third embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used.

[0067] FIG. 6 is a cross-sectional view showing the printed circuit board 20 in the circuit board 10 according to this embodiment. FIG. 6 corresponds to FIG. 2. The configuration shown in FIG. 6 is substantially the same as the configuration shown in the preceding embodiment (see FIG. 5). In this embodiment, multiple opposing wirings 411 are arranged in a common layer (the same layer). Specifically, three opposing wirings 411 (411a, 411b, 411c) are arranged in the third layer. The three opposing wirings 411 are arranged at a predetermined interval. In the cross section shown in FIG. 6, the opposing wirings 411a, 411b, and 411c are arranged in this order in the Y direction.

[0068] The potential fixed wirings 42 and 43 arranged in the second and fourth layers have protrusions 422 and 432. The protrusions 422 and 432 are provided in common to the plurality of counter wirings 411. The protrusion 422 is provided so as to cross (straddle) the plurality of counter wirings 411 in the width direction of the counter wirings 411. Similarly, the protrusion 432 is provided so as to cross (straddle) the plurality of counter wirings 411 in the width direction of the counter wirings 411.

[0069] The overlapping regions 423, 433 overlap with the arrangement regions of the multiple opposing wirings 411. The arrangement region is defined by the opposing wirings 411 located at the ends in a plan view. For example, in the arrangement direction of the opposing wirings 411, the arrangement region is defined by the outer surfaces of the opposing wirings 411a, 411c located at both ends. The peripheral regions 424, 434 are regions continuous with the overlapping regions 423, 433 and extend from the overlapping regions 423, 433 to their peripheries. The peripheral regions 424, 434 are non-overlapping regions that do not overlap with the arrangement region of the opposing wirings 411. The other configurations are the same as those exemplified in the preceding embodiment.

[0070] <Summary of the third embodiment> In this embodiment, common protrusions 422 and 432 are provided for a plurality of opposing wirings 411 arranged side by side. This simplifies the configuration and reduces impedance compared to a configuration in which the opposing wirings 411 are individually provided with protrusions 422 and 432.

[0071] When there are multiple signal wirings on the same layer, the spacing between the wirings is generally several times or more the wiring width, for example, 2 to 4 times or more. According to this embodiment, the wiring width can be narrowed, and therefore the wiring spacing can also be reduced. Therefore, an increase in the size of the printed circuit board 20 can be effectively suppressed.

[0072] In this embodiment as well, protrusions 422 and 432 are provided not only immediately above or immediately below the opposing wiring 411 but also around the periphery thereof. This increases the capacitive coupling, and the effect of reducing the impedance of the opposing wiring 411 can be enhanced.

[0073] 6, the wiring width of the opposing wiring 411a is indicated as W1a, the wiring width of the opposing wiring 411c is indicated as W1c, the width of the portion of the peripheral region 424 on the opposing wiring 411a side is indicated as W2a, and the width of the portion on the opposing wiring 411c side is indicated as W2c. If the protrusion 422 is provided so as to satisfy the relationships W2a ≧ W1a and W2c ≧ W1c, the impedance reduction effect can be enhanced, as in the case of W2 ≧ W1 shown in the previous embodiment. The same applies to the protrusion 422.

[0074] Although the opposing wiring 411 in the third layer has been exemplified, the present invention is not limited to this and may be any other layer in the inner layers or may be a surface layer.

[0075] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0076] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0077] The spatially relative terms "below" and "over" are used herein to facilitate the description of the relationship of one element or feature to another element or feature, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" other elements or features would then be oriented "over" the other elements or features. Thus, the term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0078] Although an example has been shown in which the protrusions 422, 432 are provided on only one side of the potential fixing wiring 42, 43, the present invention is not limited to this. The protrusions 422, 432 may be provided on both sides of the potential fixing wiring 42, 43. For example, in the example shown in Fig. 7, protrusions 422 are provided on both sides of the ground wiring 42 in the second layer. One of the protrusions 422 is provided so as to overlap the counter wiring 411 in the first layer. The other of the protrusions 422 is provided so as to overlap the counter wiring 411 in the third layer.

[0079] The protrusions 422 provided on both sides may be arranged so that they at least partially overlap in a plan view. In order to prevent the concentration of metal placement, it is preferable to arrange them so that they do not overlap each other, that is, to have a dispersed arrangement, as shown in Figure 7. [Explanation of symbols]

[0080] 10...circuit board, 20...printed circuit board, 20a...first surface, 20b...back surface, 30...insulating substrate, 31...insulating layer, 40...wiring, 41,412,412a,412b...Signal wiring, 411,411a,411b,411c...Opposing wiring, 42...ground wiring, 42a...opposing surface, 42b...back surface, 421...base portion, 422...protruding portion, 423...overlapping region, 424...peripheral region, 43...power supply wiring, 43a...opposing surface, 43b...back surface, 431...base portion, 432...protruding portion, 433...overlapping region, 434...peripheral region, 50...Electronic components, 60...Connector

Claims

1. An insulating substrate (30); Wiring (40) arranged in multiple layers on the insulating substrate; Equipped with the wiring includes a signal wiring (41) and potential fixed wiring (42, 43) that is fixed to a predetermined potential and is arranged to face the signal wiring via the insulating substrate in the plate thickness direction of the insulating substrate, At least one of the potential fixing wirings has a base (421, 431) and a protruding portion (422, 432) protruding in the plate thickness direction from a surface of the base facing the signal wiring, the protrusion is arranged to overlap at least one of the signal wirings in a plan view in the plate thickness direction, the signal wiring includes an opposing wiring (411) that faces the protruding portion via the insulating substrate; The protruding portion is provided in common to a plurality of the opposing wirings so as to overlap with the plurality of opposing wirings arranged in the same layer.

2. An insulating substrate (30); Wiring (40) arranged in multiple layers on the insulating substrate; Equipped with the wiring includes a signal wiring (41) and potential fixed wiring (42, 43) that is fixed to a predetermined potential and is arranged to face the signal wiring via the insulating substrate in the plate thickness direction of the insulating substrate, the potential fixing wiring has a base (421, 431), and at least one of the potential fixing wirings has a protruding portion (422, 432) protruding in the plate thickness direction from a surface of the base facing the signal wiring, the protrusion is arranged to overlap at least one of the signal wirings in a plan view in the plate thickness direction, the signal wiring includes an opposing wiring (411) that faces the protruding portion via the insulating substrate; the potential fixed wiring includes a first potential fixed wiring and a second potential fixed wiring arranged in different layers to sandwich the opposing wiring, the protrusion is provided on at least one of the first potential fixing wiring and the second potential fixing wiring; a base of the first potential fixed wiring is disposed closer to the opposing wiring in the thickness direction than a base of the second potential fixed wiring; The printed circuit board, wherein the first potential fixing wiring is provided with the protrusion.

3. An insulating substrate (30); Wiring (40) arranged in multiple layers on the insulating substrate; Equipped with the wiring includes a signal wiring (41) and potential fixed wiring (42, 43) that is fixed to a predetermined potential and is arranged to face the signal wiring via the insulating substrate in the plate thickness direction of the insulating substrate, At least one of the potential fixing wirings has a base (421, 431) and a protruding portion (422, 432) protruding in the plate thickness direction from a surface of the base facing the signal wiring, the protrusion is arranged to overlap at least one of the signal wirings in a plan view in the plate thickness direction, the signal wiring includes an opposing wiring (411) that faces the protruding portion via the insulating substrate; The potential fixing wiring having the protrusion has an overlapping region (423, 433) with the opposing wiring and a peripheral region (424, 434) connected to the overlapping region, In the printed circuit board, the length from the inner end of the peripheral region, which is the boundary with the overlapping region, to the outer end is equal to or greater than the width of the opposing wiring.

4. the potential fixed wiring includes a first potential fixed wiring and a second potential fixed wiring arranged in different layers to sandwich the opposing wiring, 4. The printed circuit board according to claim 1, wherein the protrusion is provided on at least one of the first potential fixing wiring and the second potential fixing wiring.

5. In the thickness direction, the first potential fixed wiring is disposed closer to the opposing wiring than the second potential fixed wiring; The printed circuit board according to claim 4 , wherein the first potential fixing wiring is provided with the protrusion.

6. 6. The printed circuit board according to claim 2, wherein the first potential fixing wiring and the second potential fixing wiring are each provided with the protrusion.

7. 7. The printed circuit board according to claim 1, wherein the opposing wiring is a signal wiring through which a signal having a frequency of 1 kHz or more flows.

8. 8. The printed circuit board according to claim 1, wherein the opposing wiring is a single-ended signal wiring.

9. 3. The printed circuit board according to claim 1, wherein the potential fixing wiring having the protrusion has an overlapping region (423, 433) with the opposing wiring and a peripheral region (424, 434) continuous with the overlapping region.

10. The printed circuit board according to claim 9 , wherein the length from an inner edge of the peripheral region, which is a boundary with the overlapping region, to an outer edge thereof is equal to or greater than the width of the opposing wiring.

11. 11. The printed circuit board according to claim 1, wherein the protruding portion is arranged so as to overlap at least a part of the entire length of the opposing wiring.

12. A printed circuit board (20) having an insulating substrate (30) and wiring (40) arranged in multiple layers on the insulating substrate; an electronic component (50) mounted on the printed circuit board; Equipped with The wiring includes a signal wiring (41) electrically connected to the electronic component, and potential fixed wiring (42, 43) fixed to a predetermined potential and arranged to face the signal wiring via the insulating substrate in the thickness direction of the printed circuit board, At least one of the potential fixing wirings has a base (421, 431) and a protruding portion (422, 432) protruding in the plate thickness direction from a surface of the base facing the signal wiring, the protrusion is arranged to overlap at least one of the signal wirings in a plan view in the plate thickness direction, the signal wiring includes an opposing wiring (411) that faces the protruding portion via the insulating substrate; The protruding portion is provided in common to a plurality of the opposing wirings so as to overlap with the plurality of opposing wirings arranged in the same layer.

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