JP7735904B2 - Printed Circuit Boards and Circuit Boards - Google Patents

Description

The disclosure in this specification relates to printed circuit boards and circuit boards.

Patent Document 1 discloses a printed circuit board. The contents of this prior art document are incorporated by reference as an explanation of the technical elements in this specification.

Japanese Patent Application Laid-Open No. 2006-100699

Increasing the thickness of printed circuit boards is an effective way to suppress warping caused by reflow and other processes. Increasing the thickness of the insulating layers between wiring arranged in multiple layers increases the opposing distance between signal wiring and 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 required for patterning. Therefore, increasing the width and thickness increases the physical size of the printed circuit board. Further improvements are needed in printed circuit boards and circuit boards, both from the perspectives mentioned above and from other perspectives not mentioned.

One disclosed objective is to provide a printed circuit board and a circuit board that can suppress warping while also suppressing an increase in size.

One of the printed circuit boards disclosed herein 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 so as 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,
A printed circuit board in which the protruding portion is provided in common to a plurality of opposing wirings so as to overlap with the plurality of opposing wirings arranged on the same layer .
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 so as 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 an 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 closer to the opposing wiring than a base of the second potential fixed wiring;
The first potential fixing wiring is provided with 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 so as 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 fixing wiring having a protrusion 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 .

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 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 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 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.

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

In addition, the protrusion is positioned on the opposing surface of the potential fixed wiring so that it overlaps with the opposing wiring. This makes it possible to reduce the impedance of the opposing wiring by increasing the coupling capacitance between the opposing wiring and the potential fixed wiring, as the insulating substrate (insulating layer) between the protrusion and the opposing wiring is thin. This allows the impedance to be adjusted without increasing the width or thickness of the signal wiring, thereby preventing an increase in physical size. As a result, it is possible to provide a printed circuit board and circuit board that can prevent warping while also preventing an increase in physical size.

The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference symbols in parentheses in the claims and this section are intended to illustratively indicate the correspondence with the embodiments described below and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become clearer with reference to the detailed description that follows and the accompanying drawings.

FIG. 2 is a plan view showing the circuit board according to the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 2 is a plan view showing the positional relationship between signal wiring, protrusions, and ground wiring. FIG. 10 is a cross-sectional view showing a modified example. FIG. 10 is a cross-sectional view showing a printed circuit board in a circuit board according to a second embodiment. FIG. 10 is a cross-sectional view showing a printed circuit board in a circuit board according to a third embodiment. FIG. 10 is a cross-sectional view showing a modified example.

A number of embodiments will be described below with reference to the drawings. In multiple 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 the configuration is described in each embodiment, the configuration of the other previously described embodiment may be applied to the remaining parts of that configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may also be partially combined together even if not explicitly stated, provided that there are no particular problems with the combination.

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

<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, the shape seen from a plane in the Z direction, in other words, the shape along the XY plane defined by the X direction and the Y direction, will be referred to as the planar shape. The planar view from the Z direction may sometimes be simply referred to as a planar view.

As shown in Figures 1 and 2, the circuit board 10 includes a printed circuit board 20, electronic components 50, and a connector 60. The circuitry configured on the circuit board 10 can be electrically connected to an external device via the connector 60.

The printed circuit board 20 may also be referred to as a board, wiring board, or printed wiring board. The printed circuit board 20 has one surface 20a and a back surface 20b, which is the surface opposite to the first surface 20a in the 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 generally rectangular planar shape.

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 can be made of, for example, a material containing only resin, or a material combining resin with glass cloth or nonwoven fabric. The insulating substrate 30 is formed by stacking multiple insulating layers 31. The insulating layers 31 are sometimes referred to as insulating sheets.

The number of insulating layers 31 is not particularly limited. As an example, the insulating substrate 30 of this embodiment is constructed by stacking five insulating layers 31. Of the five layers, the middle insulating layer 31 is thicker than the other insulating layers 31.

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, conductor pattern, wiring layer, 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.

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

A configuration in which wiring 40 is arranged in multiple layers on an insulating substrate 30 can be achieved by using multiple insulating layers 31, each with wiring 40 arranged on at least one surface. The printed circuit board 20 may be constructed by stacking only insulating layers 31 with wiring 40 arranged on them, or some of the multiple insulating layers 31 to be stacked may include insulating layers 31 with no wiring 40 arranged on either side. For example, an insulating layer 31 with no wiring 40 arranged on either side may be placed between insulating layers 31 with wiring 40 arranged on them. 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 when stacked.

The wiring 40 includes signal wiring 41, ground wiring 42, and power wiring 43. The signal wiring 41 may also be referred to as a signal line, signal pattern, or the like. The signal wiring 41 is electrically connected to the electronic component 50. Multiple signal wirings 41 are arranged on 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 on the insulating substrate 30.

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

The arrangement of the ground wiring 42 and power wiring 43 is not particularly limited. The number of layers of the ground wiring 42 and the number of layers of the power 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 wiring 43 is arranged so as to face at least one of the signal wiring 41 via the insulating substrate 30 (insulating layer 31).

The printed circuit board 20 includes via conductors (not shown) as circuit elements. The via conductors electrically connect wiring 40 arranged on different layers. The via conductors are sometimes referred to as connection vias or interlayer connections. The via conductors are formed by placing 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 walls of holes that penetrate the printed circuit board 20. The through holes are sometimes referred to as through-hole plating. Terminals of electronic components 50 are inserted into the through holes. The conductors on the walls of the through holes and the terminals are connected by a bonding material such as solder.

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, etc. 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, excluding lands (not shown).

The electronic components 50 are mounted on the printed circuit board 20. Multiple electronic components 50 are mounted on the printed circuit board 20. The electronic components 50 are typically arranged on one side 20a and/or the back side 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 is equipped with the electronic components 50 to provide a predetermined function.

<Protrusion and opposing wiring>
Next, the protrusion and the opposing wiring will be described with reference to FIGS.

At least one of the potential fixing wirings 42, 43, which are arranged opposite the signal wiring 41 via 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. In other words, it has a thin portion that is only the base, and a thick portion that is the base plus the protrusion. Potential fixing wirings 42, 43 with protrusions can be realized, for example, by using profiled metal foil (profile material) with partially different thicknesses. In this case, protrusions can be provided on both the surface that contacts the insulating layer 31 and its back surface. Alternatively, plated metal foil can be used. In this case, protrusions can be provided on the back surface (exposed surface) of the surface that contacts the insulating layer 31.

As an example, in this embodiment, as shown in FIG. 2, the ground wiring 42 arranged on the second layer has a base 421 and a protrusion 422. The power supply wiring 43 arranged on the fourth layer and the ground wiring 42 arranged on the fifth layer do not have a protrusion 422. In other words, they only have the base 421. The protrusion 422 protrudes in the Z direction from the surface 42a of the base 421 that faces the signal wiring 41 arranged on the third layer. In a plan view, the portion with only the base 421 is a thin-walled portion, and the portion where the protrusion 422 is provided is a thick-walled portion.

The ground wiring 42 is a so-called solid pattern. Unlike a mesh pattern, the ground wiring 42 does not have openings, and is flat with a larger area than the signal wiring 41. Solid-pattern ground wiring 42 is sometimes referred to as a solid ground. The ground wiring 42 does not have a protrusion 422 on the back surface 42b opposite the opposing surface 42a.

The protrusion 422 is arranged so as to overlap at least one of the signal wirings 41 arranged on the third layer in plan view. As an example, in Figure 2, the signal wiring 41 arranged on the third layer is the opposing wiring 411. The opposing wiring 411 faces the protrusion 422 via one insulating layer 31. The signal wiring 41 arranged on other layers, specifically the first and sixth layers, is signal wiring 412 separate from the opposing wiring 411. The signal wiring 412 is a non-opposing wiring that does not face the protrusion 422.

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

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 planar view. The overlapping region 423 is a region directly above or 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.

The protrusion 422 is arranged so as to overlap at least a portion of the opposing wiring 411 in a plan view. As an example, in this embodiment, the protrusion 422 is arranged so as to encompass the opposing wiring 411 arranged in the third layer. In other words, the protrusion 422 is arranged so as to overlap almost the entire opposing wiring 411.

Figure 3 shows an example of multiple signal wirings 41 arranged on the third layer. Figure 3 shows the positional relationship between the signal wiring 41 including the opposing wiring 411, the ground wiring 42, and the protrusion 422. For convenience, Figure 3 illustrates the signal wiring 41, the ground wiring 42, and the protrusion 422 on the same plane. In Figure 3, some of the multiple signal wirings 41 arranged on the third layer are opposing wirings 411, and the rest are signal wirings 412.

The protrusions 422 are arranged to individually enclose the opposing wiring 411 in a plan view. The protrusions 422 are arranged 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 protrusions 422 are arranged to enclose the entire meander wiring portion.

The signal wiring 412 is a pair of differential wiring 412a and 412b. In the case of the differential wiring 412a and 412b, the impedance can be adjusted by the wiring spacing. For this reason, in the example shown in Figure 3, no protrusions 422 are provided on the differential wiring 412a and 412b.

In this embodiment, the overlapping region 423 roughly coincides with the opposing wiring 411 in a planar view. The peripheral region 424 is provided to surround the opposing wiring 411 (overlapping region 423) in a planar view. The length W2 from the inner edge of the peripheral region 424, which is the boundary with the overlapping region 423, to the outer edge, 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 the direction perpendicular to the extension direction (longitudinal direction) of the opposing wiring 411.

<Summary of 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.

It is also possible to use a material with a high dielectric constant for the insulating substrate (insulating layer) to lower the impedance of the signal wiring, suppressing increases in size while achieving impedance matching with electronic components. However, this increases dielectric loss.

In this embodiment, the ground wiring 42 (potential fixing wiring) on the second layer, which faces the signal wiring 41 on the third layer via the insulating layer 31 (insulating substrate 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 that faces the protrusion 422 via the insulating layer 31.

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

Furthermore, by arranging the protrusion 422 at a position overlapping the opposing wiring 411 on the opposing surface 42a of the ground wiring 42, the insulating layer 31 interposed between the protrusion 422 and the opposing wiring 411 is thin. In other words, the opposing distance between the protrusion 422 (ground wiring 42) and the opposing wiring 411 is short. This increases the coupling capacitance between the opposing wiring 411 and the ground wiring 42, thereby reducing the impedance of the opposing wiring 411. Because 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, this embodiment can suppress warping while also suppressing an increase in physical size. Furthermore, because a material with a high dielectric constant does not need to be used for the insulating substrate 30 (insulating layer 31), the above-mentioned effects can be achieved while reducing dielectric loss.

The protrusion height of the protrusion 422 is not particularly limited. It can be set within a range that ensures electrical insulation between the protrusion 422 and the opposing wiring 411. The higher the protrusion height, i.e., the shorter the opposing distance between the protrusion 422 and the opposing wiring 411, the greater the effect of reducing the impedance of the opposing wiring 411.

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

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 above 1 kHz, impedance management, i.e., impedance matching, becomes important. Stricter management is required particularly at frequencies above 100 MHz. According to this embodiment, a protrusion 422 is provided corresponding to the opposing wiring 411 through which a signal with a frequency of 1 kHz or higher flows, thereby suppressing losses due to impedance mismatch between the opposing wiring 411 and the electronic component 50.

The opposing wiring 411 may include only single-ended wiring, or only differential wiring. The opposing wiring 411 may also include both. With differential wiring, impedance can be adjusted by the wiring spacing. With single-ended wiring, impedance cannot be adjusted by the wiring spacing as with differential wiring. For this reason, if you try to suppress warping, an increase in physical size becomes a problem. In this embodiment, by providing the protrusion 422 as described above, it is possible to suppress an increase in physical size while using single-ended wiring as the opposing wiring 411.

The protrusion 422 may be positioned so as to overlap at least a portion of the entire length of the opposing wiring 411. The impedance of the opposing 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, improving design freedom. For example, the protrusion 422 may be positioned so as to overlap only a portion of the entire length of the opposing wiring 411.

The radiated electric field of the opposing wiring 411 has a predetermined spread. The electric field strength is high not only directly above or directly below the opposing wiring 411, but also in the surrounding area. In this embodiment, protrusions 422 are provided not only directly above the opposing wiring 411, but also in the surrounding area. This increases capacitive coupling and enhances the effect of reducing the impedance of the opposing wiring 411. In particular, because the protrusions 422 are provided so as to satisfy the relationship W2≧W1, the effect of reducing the impedance of the opposing wiring 411 can be further enhanced.

In this way, the impedance of the opposing wiring 411 can also be adjusted by changing the width W2 of the peripheral region 424. In addition to the height of the protrusion 422, the number of parameters for adjusting impedance increases, improving design freedom.

<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 the counter wiring 411, and the rest may be used as the signal wiring 412. All of the multiple signal wirings 41 arranged on a common layer may be used as the counter wiring 411. The presence or absence of the protrusion 422 makes it possible to select the counter wiring 411 and the signal wiring 412. This improves the degree of freedom in designing the signal wiring 41.

Although an example has been shown in which a 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, a protrusion 422 is provided on the surface of the second layer ground wiring 42 facing the first layer. Alternatively, the signal wiring 41 arranged on the sixth layer (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.

In a configuration in which the potential fixed wiring 42, 43 are arranged to sandwich the opposing wiring 411, the distance L2 between the power supply wiring 43 and the opposing wiring 411 may be shorter than the distance L1 between the ground wiring 42 (base 421) and the opposing 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.

The configuration of the peripheral region 424 is not limited to the example described above. 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.

Second Embodiment
This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used.

Figure 5 is a cross-sectional view showing the printed circuit board 20 in the circuit board 10 according to this embodiment. Figure 5 corresponds to Figure 2.

As in the previous embodiment, in this embodiment, potential fixing wiring 42, 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 protrusion 422. In this embodiment, the power supply wiring 43 in the fourth layer also has a base 431 and a protrusion 432. The protrusion 432 protrudes in the Z direction from the surface 43a of the base 431 that faces the signal wiring 41 arranged in the third layer. In a plan view, the portion containing only the base 431 is a thin portion, and the portion where the protrusion 432 is provided is a thick portion. The protrusion 432 is not provided on the back surface 43b of the opposing surface 43a.

As in the previous embodiment, the distance L1 between the base 421 of the ground wiring 42 and the opposing wiring 411 is shorter than the distance L2 between the base 431 of the power supply wiring 43 and the opposing 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.

As in 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 planar view. The overlapping region 433 is a region directly above or 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.

The protrusion 432 is arranged to overlap at least a portion of the opposing wiring 411 in a plan view. The other configurations are the same as those exemplified in the previous embodiment.

<Summary of the Second Embodiment>
In this embodiment, the power supply wiring 43 is also arranged to face the opposing wiring 411 with the insulating layer 31 interposed therebetween. The power supply wiring 43 has a protrusion 432 provided to overlap the opposing wiring 411 in a plan view. The opposing 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 opposing wiring 411 are provided with protrusions 422 and 432, respectively. This makes it possible to further reduce the impedance of the opposing wiring 411.

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 set the impedance to 50 ohms without providing protrusions 422 and 432. In contrast, by providing 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%, effectively suppressing increases in physical size. Note that in the potential fixed wiring 42 and 43 having protrusions 422 and 432, the thickness of the bases 421 and 431 is 35 μm.

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

The potential fixing wiring arranged to sandwich the opposing wiring 411 is not limited to the combination of the ground wiring 42 and the power supply wiring 43. For example, the opposing wiring 411 may be arranged between the ground wiring 42, or the opposing wiring 411 may be arranged between the power supply wiring 43.

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

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

The potential fixing wirings 42, 43 arranged on the second and fourth layers have protrusions 422, 432. The protrusions 422, 432 are provided in common to multiple opposing wirings 411. The protrusion 422 is provided so as to cross (straddle) the multiple opposing wirings 411 in the width direction of the opposing wirings 411. Similarly, the protrusion 432 is provided so as to cross (straddle) the multiple opposing wirings 411 in the width direction of the opposing wirings 411.

The overlapping regions 423, 433 overlap with the arrangement regions of multiple opposing wirings 411. The arrangement regions are 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 regions are defined by the outer surfaces of the opposing wirings 411a, 411c located at both ends. The peripheral regions 424, 434 are regions that are 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 regions of the opposing wirings 411. The rest of the configuration is the same as the configuration illustrated in the previous embodiment.

<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.

When there are multiple signal wirings on the same layer, the spacing between the wirings is generally several times the wiring width, for example, two to four times or more. According to this embodiment, the wiring width can be narrowed, and therefore the wiring spacing can also be reduced. This effectively prevents the physical size of the printed circuit board 20 from increasing.

In this embodiment, protrusions 422, 432 are provided not only directly above or directly below the opposing wiring 411, but also around the periphery. This increases capacitive coupling and enhances the effect of reducing the impedance of the opposing wiring 411.

In Figure 6, the wiring width of the opposing wiring 411a is shown as W1a, the wiring width of the opposing wiring 411c is shown as W1c, the width of the portion of the peripheral region 424 on the opposing wiring 411a side is shown as W2a, and the width of the portion on the opposing wiring 411c side is shown as W2c. If the protrusion 422 is provided so that the relationships W2a ≥ W1a and W2c ≥ W1c are satisfied, the impedance reduction effect can be enhanced, as with W2 ≥ W1 shown in the previous embodiment. The same applies to the protrusion 422.

Although the opposing wiring 411 on the third layer is shown as an example, this is not limiting. It may be on another inner layer or on the surface layer.

(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.

The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas set forth in the claims, and extends to technical ideas that are more diverse and extensive than the technical ideas set forth in the claims. Therefore, a variety of technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

The spatially relative terms "below" and "over" are used herein for ease of description to describe 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 also be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

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, this is not limiting. The protrusions 422, 432 may be provided on both sides of the potential fixing wiring 42, 43. For example, in the example shown in Figure 7, protrusions 422 are provided on both sides of the second-layer ground wiring 42. One of the protrusions 422 is provided so as to overlap the opposing wiring 411 of the first layer. The other protrusion 422 is provided so as to overlap the opposing wiring 411 of the third layer.

The protrusions 422 on both sides may be arranged so that they at least partially overlap in a plan view. To prevent the concentration of metal placement, a non-overlapping arrangement, i.e., a dispersed arrangement, as shown in Figure 7, is preferred.

10...circuit board,
20...printed circuit board, 20a...one side, 20b...back side,
30...insulating substrate, 31...insulating layer,
40...wiring,
41, 412, 412a, 412b...signal wiring,
411, 411a, 411b, 411c...opposite wiring,
42...ground wiring, 42a...opposing surface, 42b...back surface,
421...base portion, 422...protrusion portion, 423...overlapping region, 424...peripheral region,
43...power supply wiring, 43a...opposing surface, 43b...back surface,
431...base portion, 432...protrusion portion, 433...overlapping region, 434...peripheral region,
50...Electronic components,
60...Connector

Claims (12)

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