JP2024017063A - wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board with which an increase in the electrostatic capacitance of differential pair conductors is suppressed, and the possibility of erroneous operation due to the mutual inclusion of noise between the differential pair conductors is reduced.

SOLUTION: A wiring board according to the present disclosure includes a laminate unit comprising a plurality of insulating layers that are mutually laminated and have a plurality of via holes, and a plurality of wiring conductors that are arranged on the surface of the insulating layers and in the via holes. The wiring conductors include a first pair conductors and a second pair conductors extending adjacent to each other. The first pair conductors and the second pair conductors include two line conductors, respectively. The line conductors have a plurality of land conductors located on the surface of insulating layers and a plurality of via hole conductors that are located in the via holes and connect to the land conductors. The first pair conductors include a plurality of first via hole conductors, as well as a first land conductor and a second land conductor. The second pair conductors include a plurality of second via hole conductors, as well as a third land conductor and a fourth land conductor. The second and fourth land conductors are located between different layers of the plurality of insulating layers.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a wiring board and a mounting structure using the same.

In conventional wiring boards, a plurality of via hole conductors are sometimes stacked to electrically connect layers of build-up insulating layers. In this manner, when a plurality of via hole conductors are stacked, the stress applied to the stacked portion of the via hole conductors increases as the number of via hole conductors increases. Therefore, as described in Patent Document 1, the applied stress may be alleviated by shifting the stacking positions of a plurality of via hole conductors in the middle.

However, when the differential pair conductors are located adjacent to each other, the capacitance between the differential pair conductors increases in a via land portion for shifting the laminated via hole conductors. Therefore, the possibility of malfunction due to mutual mixing of noise between the differential pair conductors increases.

JP2019-121772

An object of the present disclosure is to provide a wiring board with high electrical reliability, in which increase in capacitance between differential pair conductors is reduced and mutual mixing of noise between differential pair conductors is reduced.

The wiring board according to the present disclosure has (1) a laminated portion including a plurality of insulating layers stacked on each other and having a plurality of via holes, and a plurality of wiring conductors located on the surface of the insulating layer and in the via holes. The wiring conductor includes a first pair of conductors and a second pair of conductors that extend adjacent to each other. The first pair of conductors and the second pair of conductors each include two line conductors. The line conductor has a plurality of land conductors located on the surface of the insulating layer and a plurality of via hole conductors located in the via holes and connected to the land conductors. The first pair of conductors includes a plurality of first via hole conductors among the via hole conductors, and a first land conductor and a second land conductor among the land conductors. The second pair of conductors includes a plurality of second via hole conductors among the via hole conductors, and a third land conductor and a fourth land conductor among the land conductors. The first land conductor connects the first via hole conductors that are located so as to overlap each other when seen in plan view, and the second land conductor has a shape longer in the first direction than the first land conductor, and the second land conductor has a shape that is longer in the first direction than the first land conductor. The first via hole conductors located apart from each other along one direction are connected to each other. The third land conductor connects the second via hole conductors that are located so as to overlap each other when viewed in plan view, and the fourth land conductor has a shape that is longer in the first direction than the third land conductor, and The second via hole conductors located apart from each other along one direction are connected to each other. The second land conductor and the fourth land conductor are located between different layers of the plurality of insulating layers.

(2) In the wiring board according to (1) above, the first pair of conductors and the second pair of conductors are adjacent to each other in a direction along the direction in which the via hole conductors each of the two line conductors have are lined up.
(3) In the wiring board according to (1) or (2) above, the first pair of conductors and the second pair of conductors are adjacent to each other in a direction intersecting the direction in which the via hole conductors of the two line conductors are arranged. ing.
(4) In the wiring board according to any one of (1) to (3) above, in the second land conductor of the first pair conductor and the fourth land conductor of the second pair conductor, which are located adjacent to each other. , the second land conductor is located in an insulating layer one above or one insulating layer below the insulating layer where the fourth land conductor is located.
(5) In the wiring board according to any one of (1) to (4) above, the number of laminated layers of via hole conductors positioned so as to overlap each other in plan view is 2 or more and 5 or less.
(6) In the wiring board according to any one of (1) to (5) above, the first pair of conductors and the second pair of conductors are signal conductors.

A mounting structure according to the present disclosure includes (7) the wiring board according to any one of (1) to (6) above, and an electronic component located in the mounting area of the wiring board.

By having the above configuration, the wiring board according to the present disclosure suppresses an increase in capacitance between the differential pair conductors, and reduces the risk of malfunction due to mutual mixing of noise between the differential pair conductors. It can be lowered.

FIG. 2 is an explanatory diagram for explaining a mounting structure in which electronic components are mounted on a wiring board according to an embodiment of the present disclosure. 2 is an explanatory diagram schematically showing an embodiment regarding the arrangement of land conductors and via hole conductors in region X shown in FIG. 1. FIG. 2 is an explanatory diagram schematically showing another embodiment regarding the arrangement of land conductors and via hole conductors in region X shown in FIG. 1. FIG. 2 is an explanatory diagram schematically showing still another embodiment regarding the arrangement of land conductors and via hole conductors in region X shown in FIG. 1. FIG. 2 is an explanatory diagram schematically showing still another embodiment regarding the arrangement of land conductors and via hole conductors in region X shown in FIG. 1. FIG.

A wiring board according to an embodiment of the present disclosure will be described based on FIGS. 1 and 2. FIG. 1 is an explanatory diagram for explaining a mounting structure 10 in which an electronic component 8 is mounted on a wiring board 1 according to an embodiment of the present disclosure. The wiring board 1 according to one embodiment includes a core layer 2, a laminated portion 5, and a solder resist 6.

The core layer 2 is not particularly limited as long as it is made of an insulating material. Examples of the material having insulation properties include resins such as epoxy resin, bismaleimide-triazine resin, polyimide resin, and polyphenylene ether resin. These resins may be used in combination of two or more. The thickness of the core layer 2 is not particularly limited, and is, for example, 100 μm or more and 800 μm or less.

The core layer 2 may include a reinforcing material. Examples of the reinforcing material include insulating cloth materials such as glass fiber, glass nonwoven fabric, aramid nonwoven fabric, aramid fiber, and polyester fiber. Two or more reinforcing materials may be used in combination. Furthermore, inorganic insulating fillers such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide may be dispersed in the core layer 2.

A through-hole conductor is located in the core layer 2 in order to electrically connect the upper and lower surfaces of the core layer 2. The through-hole conductor is located in a through-hole that penetrates the core layer 2 from the top surface to the bottom surface. The through-hole conductor is formed of, for example, metal plating such as copper plating. The through-hole conductors are connected to wiring conductors 4 located on both sides of the core layer 2. The through-hole conductor may be located only on the inner wall surface of the through-hole, or may be filled within the through-hole.

Laminated portions 5 are located on the upper and lower surfaces of the core layer 2 . The laminated portion 5 has a structure in which an insulating layer 3 and a wiring conductor 4 are laminated. Similar to the core layer 2, the insulating layer 3 is not particularly limited as long as it is made of an insulating material. Examples of the material having insulation properties include resins such as epoxy resin, bismaleimide-triazine resin, polyimide resin, and polyphenylene ether resin. These resins may be used in combination of two or more. The insulating layers 3 may be made of the same resin or different resins. The insulating layer 3 and the core layer 2 may be made of the same resin or different resins.

The insulating layer 3 may include a reinforcing material. Examples of the reinforcing material include insulating cloth materials such as glass fiber, glass nonwoven fabric, aramid nonwoven fabric, aramid fiber, and polyester fiber. Two or more reinforcing materials may be used in combination. Furthermore, inorganic insulating fillers such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide may be dispersed in the insulating layer 3. The thickness of the insulating layer 3 is not particularly limited, and is, for example, 10 μm or more and 50 μm or less. The insulating layers 3 may each have the same thickness or may have different thicknesses.

The wiring conductor 4 is not limited as long as it is a conductor such as metal. Specifically, the wiring conductor 4 is formed of metal foil such as copper foil, metal plating such as copper plating, or the like. The thickness of the wiring conductor 4 is not particularly limited, and is, for example, 5 μm or more and 25 μm or less.

As shown in FIG. 1, a solder resist 6 may be located on the surface of the laminated portion 5. The solder resist 6 is made of resin, and examples of the resin include acrylic modified epoxy resin. An opening is provided in the solder resist 6 in order to electrically connect the wiring conductor 4 and the electrode of the electronic component 8 via the solder 7. Examples of the electronic component 8 include a semiconductor integrated circuit element, an optoelectronic element, and the like.

In the wiring board 1 according to one embodiment, at least a portion of the wiring conductor 4 includes a first pair conductor 411 and a second pair conductor 412 that extend adjacent to each other, as shown in FIG. FIG. 2 is an explanatory diagram schematically showing an embodiment regarding the arrangement of land conductors 4a and via hole conductors 4b in region X shown in FIG. In FIG. 2, the insulating layer 3 is omitted. The first pair conductor 411 and the second pair conductor 412 are, for example, signal conductors.

The first pair conductor 411 and the second pair conductor 412 each include two line conductors 4'. The line conductors 4' are located adjacent to each other, and, for example, the two line conductors 4' function as a differential line. The line conductor 4' has a plurality of land conductors 4a located on the surface of the insulating layer 3, and a plurality of via hole conductors 4b located in via holes penetrating from the upper surface to the lower surface of the insulating layer 3 and connected to the land conductors 4a. . The via hole conductor 4b may be filled in the via hole or may be located only on the inner wall surface of the via hole.

The first pair conductor 411 includes a plurality of first via hole conductors 4b1 among the via hole conductors 4b, and a first land conductor 4a1 and a second land conductor 4a2 among the land conductors 4a. The first land conductor 4a1 connects the first via hole conductors 4b1 that are positioned so as to overlap each other when viewed from above. The shape of the first land conductor four a1 is not limited as long as it can be connected to the first via hole conductor four b1. The first land conductor 4a1 has, for example, a polygonal shape such as a circular shape or a rectangular shape (square shape). The first land conductors 4a1 may have the same shape, may have different shapes, may have the same size, or may have different sizes.

The number of stacked layers of the first via hole conductors 4b1 positioned so as to overlap each other in plan view may be, for example, 2 or more and 5 or less. With such a number of laminated layers, it is possible to reduce the area in which the via hole conductor 4b is arranged, and it is also possible to efficiently alleviate the stress applied to the connection portion between the land conductor 4a and the via hole conductor 4b.

The second land conductor 4a2 has a longer shape in the first direction D1 than the first land conductor 4a1, and connects the first via hole conductors 4b1 that are spaced apart from each other along the first direction D1 in plan view. ing. That is, the dimension of the second land conductor 4a2 in the first direction D1 is larger than the dimension of the first land conductor 4a1 in the first direction D1. The first direction D1 means any one direction along the surface of the insulating layer 3. In other words, the first direction D1 can be said to be the extending direction of an imaginary line connecting the center points of the via hole conductors that are located at different positions and separated from each other when viewed from the top. The shape of the second land conductor 4a2 is not limited as long as it can connect the first via hole conductors 4b1 located on the upper surface side and the lower surface side of the second land conductor 4a2 at positions separated from each other. Examples of the shape of the second land conductor 4a2 include a shape having a major axis (long side) and a minor axis (short side), such as an elliptical shape or a rectangular shape. The second land conductor 4a2 is located so that its major axis (long side) is parallel to the first direction. The second land conductors 4a2 may have the same shape, may have different shapes, may have the same size, or may have different sizes. The size relationship between the dimension of the second land conductor 4a2 in the direction perpendicular to the first direction D1 and the dimension of the first land conductor 4a1 in the direction perpendicular to the first direction D1 does not matter.

The second pair conductor 412 includes a plurality of second via hole conductors 4b2 among the via hole conductors 4b, and a third land conductor 4a3 and a fourth land conductor 4a4 among the land conductors 4a. The third land conductor 4a3 connects the second via hole conductors 4b2 which are positioned so as to overlap each other when viewed from above. The shape of the third land conductor 4a3 is not limited as long as it can be connected to the second via hole conductor 4b2. The shape of the third land conductor four a3 has, for example, a polygonal shape such as a circular shape or a rectangular shape (square shape), like the first land conductor four a1. The third land conductors 4a3 may have the same shape, may have different shapes, may have the same size, or may have different sizes.

The number of laminated layers of the second via hole conductors 4b2, which are positioned so as to overlap each other in plan view, may be, for example, 2 or more and 5 or less, similar to the number of laminated layers of the first via hole conductors 4b1. With such a number of laminated layers, it is possible to reduce the area in which the via hole conductor 4b is arranged, and it is also possible to efficiently alleviate the stress applied to the connection portion between the land conductor 4a and the via hole conductor 4b.

The fourth land conductor 4a4 has a longer shape in the first direction D1 than the third land conductor 4a3, and connects the second via hole conductors 4b2 that are spaced apart from each other along the first direction D1 in plan view. ing. That is, the dimension of the fourth land conductor four a4 in the first direction D1 is larger than the dimension of the third land conductor four a3 in the first direction D1. The first direction D1 is as described above. The shape of the fourth land conductor four a4 is not limited as long as it can connect the second via hole conductors four b2 located on the upper surface side and the lower surface side of the fourth land conductor four a4 at positions separated from each other. Examples of the shape of the fourth land conductor 4a4 include a shape having a major axis (long side) and a minor axis (short side), such as an elliptical shape or a rectangular shape. The fourth land conductor 4a4 is located so that its major axis (long side) is substantially parallel to the first direction D1. The fourth land conductors 4a4 may each have the same shape, may have different shapes, may have the same size, or may have different sizes. The size relationship between the dimension of the fourth land conductor 4a4 in the direction perpendicular to the first direction D1 and the dimension of the third land conductor 4a3 in the direction perpendicular to the first direction D1 does not matter.

In the wiring board 1 according to one embodiment, the second land conductor 4a2 and the fourth land conductor 4a4 are located between different layers of the plurality of insulating layers 3. That is, the second land conductor 4a2 and the fourth land conductor 4a4 are not located on the same insulating layer 3. By having such a configuration, the capacitance between the first pair conductor 411 and the second pair conductor 412 is reduced. As a result, the risk of malfunction due to mutual mixing of noise between differential lines can be reduced.

The difference between the second land conductor 4a2 and the fourth land conductor 4a4 is not limited as long as they are located between different layers of the plurality of insulating layers 3. The second land conductor 4a2 may be located, for example, in the insulating layer 3 one above or one below the insulating layer 3 where the fourth land conductor 4a4 is located. In FIG. 2, the second land conductor 4a2 is located in the insulating layer 3 one level below the insulating layer 3 where the fourth land conductor 4a4 is located. In FIG. 2, the insulating layer 3 is omitted as described above.

Alternatively, as shown in FIG. 3, the second land conductor 4a2 may be located in the insulating layer 3 three levels below the insulating layer 3 where the fourth land conductor 4a4 is located. That is, the second land conductor 4a2 may be located, for example, in the insulating layer 3 one to three layers above or one to three layers below the insulating layer 3 where the fourth land conductor 4a4 is located. good. FIG. 3 is an explanatory diagram schematically showing another embodiment regarding the arrangement of land conductors 4a and via hole conductors 4b in region X shown in FIG. In FIG. 3, the insulating layer 3 is omitted.

The second land conductor 4a2 is located in the insulating layer 3 1 to 3 layers above or 1 to 3 layers below the insulating layer 3 where the fourth land conductor 4a4 is located. The capacitance between the pair conductor 411 and the second pair conductor 412 is further reduced. In particular, the second land conductor 4a2 is located one to three insulating layers 3 above or one to three insulating layers 3 below the insulating layer 3 where the fourth land conductor 4a4 is located. An excellent suppressing effect on increase in capacitance is exhibited.

In FIGS. 2 and 3, the first pair conductor 411 and the second pair conductor 412 are adjacent to each other in the direction along the direction in which the via hole conductors 4b of the two line conductors 4' are lined up. That is, in FIGS. 2 and 3, the major axis of the second land conductor 4a2 and the major axis of the fourth land conductor 4a4 are in the direction along the linear line conductor 4' of the first pair conductor 411 and the second pair conductor 412, respectively. positioned. In FIGS. 2 and 3, the "first direction D1" is a direction along the linear line conductor 4' of the first pair conductor 411 and the second pair conductor 412. Since the first pair conductor 411 and the second pair conductor 412 are adjacent to each other in the direction in which the via hole conductors 4b of the two lines are arranged, the phase difference of the signals propagating through the two lines is matched. becomes easier.

As shown in FIGS. 4 and 5, the first pair conductor 411 and the second pair conductor 412 may be adjacent to each other in a direction intersecting the direction in which the via hole conductors 4b of the two line conductors 4' are arranged. good. That is, in FIGS. 4 and 5, the major axis of the second land conductor 4a2 and the major axis of the fourth land conductor 4a4 may be located in the direction intersecting the first pair conductor 411 and the second pair conductor 412, respectively. In FIGS. 4 and 5, the "first direction D1" is a direction intersecting the first pair conductor 411 and the second pair conductor 412. 4 and 5 are explanatory diagrams schematically showing still other embodiments regarding the arrangement of land conductors 4a and via hole conductors 4b in region X shown in FIG.

In FIG. 4, the second land conductor 4a2 is located in the insulating layer 3 one level below the insulating layer 3 where the fourth land conductor 4a4 is located. In FIG. 5, the second land conductor 4a2 is located in the insulating layer 3 three levels below the insulating layer 3 where the fourth land conductor 4a4 is located. In FIGS. 4 and 5, the insulating layer 3 is omitted. The first pair conductor 411 and the second pair conductor 412 are adjacent to each other in the direction intersecting the direction in which the via hole conductors 4b of the two lines are arranged, so that the first pair conductor 411 and the second pair conductor 412 can be arranged more densely.

A mounting structure according to the present disclosure includes a wiring board 1 according to an embodiment and an electronic component 8 located on the surface of the wiring board 1. The wiring conductor 4 (pad) in the opening of the solder resist 6 and the electrode of the electronic component 8 are connected via the solder 7. As described above, examples of the electronic component 8 include a semiconductor integrated circuit element, an optoelectronic element, and the like. The electronic components 8 may be located on both sides of the wiring board 1, and the electronic components 8 may be located on one surface and, for example, a motherboard or the like may be located on the other surface.

The wiring board according to the present disclosure is not limited to the above-described embodiments. In the above-described wiring board 1, six layers of wiring conductors 4 are laminated in the laminated portion 5. However, the number of laminated layers of the wiring conductor 4 may be at least more than six layers, and may be more than six layers. Further, depending on the number of laminated wiring conductors 4, two or more second land conductors 4a2 and four fourth land conductors 4a4 may be provided on one line conductor 4'.

Specifically, in FIG. 2, one line conductor 4' constituting the first pair conductor 411 is provided with a second land conductor 4a2 in the third layer from the bottom among the land conductors 4a. When the number of laminated wiring conductors 4 is larger, a second land conductor 4a2 may be further provided, for example, in the sixth layer from the bottom among the land conductors 4a. That is, when the number of laminated wiring conductors 4 is large, a plurality of second land conductors 4a2 may be provided, for example, every 2 to 5 layers. The same applies to the fourth land conductor 4a4.

1 Wiring board 2 Core layer 3 Insulating layer 4 Wiring conductor 411 1st pair conductor 412 2nd pair conductor 4' Line conductor 4a Land conductor 4a1 1st land conductor 4a2 2nd land conductor 4a3 3rd land conductor 4a4 4th land conductor 4b Via hole conductor 4b1 First via hole conductor 4b2 Second via hole conductor 5 Laminated portion 6 Solder resist 7 Solder 8 Electronic component 10 Mounting structure

Claims (7)

A laminated portion having a plurality of insulating layers stacked on each other and having a plurality of via holes, and a plurality of wiring conductors located on the surface of the insulating layers and in the via holes,
The wiring conductor includes a first pair conductor and a second pair conductor extending adjacent to each other,
The first pair of conductors and the second pair of conductors each include two line conductors,
The line conductor has a plurality of land conductors located on the surface of the insulating layer, and a plurality of via hole conductors located in the via hole and connected to the land conductor,
The first pair of conductors includes a plurality of first via hole conductors among the via hole conductors, and a first land conductor and a second land conductor among the land conductors,
The second pair of conductors includes a plurality of second via hole conductors among the via hole conductors, and a third land conductor and a fourth land conductor among the land conductors,
The first land conductor connects the first via hole conductors that are positioned so as to overlap each other in plan view,
The second land conductor has a longer shape in the first direction than the first land conductor, and connects the first via hole conductors located apart from each other along the first direction in plan view,
The third land conductor connects the second via hole conductors that are positioned so as to overlap each other in plan view,
The fourth land conductor has a longer shape in the first direction than the third land conductor, and connects the second via hole conductors located apart from each other along the first direction in plan view,
The second land conductor and the fourth land conductor are located between different layers of the plurality of insulating layers,
wiring board. The wiring board according to claim 1, wherein the first pair of conductors and the second pair of conductors are adjacent to each other in a direction along a direction in which the via hole conductors of the two line conductors are arranged. The wiring board according to claim 1, wherein the first pair of conductors and the second pair of conductors are adjacent to each other in a direction intersecting a direction in which the via hole conductors of the two line conductors are arranged. In the second land conductor of the first pair of conductors and the fourth land conductor of the second pair of conductors that are located adjacent to each other, the second land conductor is located where the fourth land conductor is located. The wiring board according to claim 1, wherein the wiring board is located on the insulating layer one above or one below the insulating layer. 2. The wiring board according to claim 1, wherein the number of laminated layers of the via hole conductors that are positioned so as to overlap each other when viewed from above is 2 or more and 5 or less. The wiring board according to claim 1, wherein the first pair of conductors and the second pair of conductors are signal conductors. A mounting structure comprising the wiring board according to claim 1 and an electronic component located in a mounting area of the wiring board.

Images