Wiring boards and mounting structures

Abstract

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

Description

Technical Field

[0001] The present invention relates to a wiring board and a mounting structure using the same.

Background Art

[0002] In a conventional wiring board, in order to electrically connect between layers of an insulating layer for build-up, a plurality of via-hole conductors may be laminated. Thus, when a plurality of via-hole conductors are laminated, the stress applied to the laminated portion of the via-hole conductors increases as the number of laminated conductors increases. Therefore, as described in Patent Document 1, the position where the conductors are laminated may be shifted in the middle of the plurality of via-hole conductors to relieve the applied stress.

[0003] However, when differential pair conductors are positioned adjacent to each other, the capacitance between the differential pair conductors increases in the 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.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a wiring board with high electrical reliability in which an increase in capacitance between differential pair conductors is reduced and mutual mixing of noise between differential pair conductors is reduced.

Means for Solving the Problems

[0006] The wiring board according to this disclosure has (1) a laminated portion having a plurality of insulating layers stacked on top of 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 conductors are adjacent to each other It includes the two track conductors located there. It includes a first pair of conductors and a second pair of conductors. The first pair of conductors and the second pair of conductors are They are located adjacent to each other at a distance greater than the distance between the two track conductors. . two The track conductor each The conductor has multiple land conductors located on the surface of the insulating layer, and multiple via hole conductors located in via holes and connecting to the land conductors. The first pair of conductors includes multiple first via hole conductors from among the via hole conductors, and a first land conductor and a second land conductor from among the land conductors. The second pair of conductors includes multiple second via hole conductors from among the via hole conductors, and a third land conductor and a fourth land conductor from among the land conductors. The first land conductors connect first via hole conductors that are located so as to overlap each other in a planar view, and the second land conductors have a shape that is longer in the first direction than the first land conductors and connect first via hole conductors that are located spaced apart from each other along the first direction in a planar view. The third land conductors connect second via hole conductors that are located so as to overlap each other in a planar view, and the fourth land conductor has a shape that is longer in the first direction than the third land conductor and connects second via hole conductors that are located spaced apart from each other along the first direction in a planar view. The second and fourth land conductors are located between different layers of the multiple insulating layers.

[0007] (2) In the wiring board described in (1) above, the first pair of conductors and the second pair of conductors are arranged in a direction along the direction in which the via hole conductors of each of the two line conductors are aligned. Spaced apart (3) In the wiring board described in (1) or (2) above, the first pair of conductors and the second pair of conductors are arranged in directions that intersect with the direction in which the via hole conductors of each of the two line conductors are arranged. Spaced apart They are doing it. (4) In the wiring board described in any of (1) to (3) above, separationIn the second land conductor of the first pair of conductors and the fourth land conductor of the second pair of conductors, the second land conductor is located in the insulating layer one level above or one level below the insulating layer in which the fourth land conductor is located. (5) In the wiring board described in any of (1) to (4) above, the number of layers of via-hole conductors that overlap each other in a planar perspective view is 2 to 5 layers. (6) In the wiring board described in any of (1) to (5) above, the first pair of conductors and the second pair of conductors are signal conductors.

[0008] The implementation structure relating to this disclosure comprises (7) a wiring board as described in any of (1) to (6) above, and an electronic component located in the mounting area of ​​the wiring board. [Effects of the Invention]

[0009] The wiring board according to this disclosure, having the above-described configuration, suppresses the increase in capacitance between differential pair conductors and reduces the risk of malfunction due to the mutual mixing of noise between differential pair conductors. [Brief explanation of the drawing]

[0010] [Figure 1] This is an explanatory diagram illustrating a mounting structure in which electronic components are mounted on a wiring board according to one embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic explanatory diagram showing one embodiment of the arrangement of land conductors and via hole conductors in region X. [Figure 3] Figure 1 shows a schematic diagram illustrating another embodiment of the arrangement of land conductors and via hole conductors in region X. [Figure 4] Figure 1 shows a schematic diagram illustrating yet another embodiment of the arrangement of land conductors and via hole conductors in region X. [Figure 5] Figure 1 shows a schematic diagram illustrating yet another embodiment of the arrangement of land conductors and via hole conductors in region X. [Modes for carrying out the invention]

[0011] A wiring board according to one embodiment of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is an explanatory diagram for illustrating a mounting structure 10 on which electronic components 8 are mounted on a wiring board 1 according to one 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.

[0012] The core layer 2 is not particularly limited as long as it is made of an insulating material. Examples of insulating materials include epoxy resins, bismaleimide-triazine resins, polyimide resins, and polyphenylene ether resins. Two or more of these resins may be used in mixture form. The thickness of the core layer 2 is not particularly limited, for example, 100 μm to 800 μm.

[0013] Core layer 2 may contain reinforcing materials. Examples of reinforcing materials include insulating fabrics such as glass fibers, glass nonwoven fabrics, aramid nonwoven fabrics, aramid fibers, and polyester fibers. Two or more types of reinforcing materials may be used in combination. Furthermore, inorganic insulating fillers such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium dioxide may be dispersed in core layer 2.

[0014] The core layer 2 has through-hole conductors to electrically connect its upper and lower surfaces. The through-hole conductors are located within through-holes that penetrate from the upper surface to the lower surface of the core layer 2. The through-hole conductors are formed by, 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 conductors may be located only on the inner wall surface of the through-holes, or they may be filled inside the through-holes.

[0015] On the upper and lower surfaces of the core layer 2, there are laminated portions 5. The laminated portion 5 has a structure in which an insulating layer 3 and a wiring conductor 4 are laminated. The insulating layer 3 is not particularly limited as long as it is a material having insulating properties, similar to the core layer 2. Examples of the material having insulating properties include resins such as epoxy resin, bismaleimide-triazine resin, polyimide resin, and polyphenylene ether resin. These resins may be used by mixing two or more kinds. The insulating layers 3 may be the same resin or different resins. The insulating layer 3 and the core layer 2 may be the same resin or different resins.

[0016] The insulating layer 3 may contain a reinforcing material. Examples of the reinforcing material include insulating cloth materials such as glass fiber, glass non-woven fabric, aramid non-woven fabric, aramid fiber, and polyester fiber. Two or more kinds of reinforcing materials may be used in combination. Further, 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 have the same thickness or different thicknesses.

[0017] The wiring conductor 4 is not limited as long as it is a conductor such as a metal. Specifically, the wiring conductor 4 is formed of a metal foil such as copper foil, a 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.

[0018] 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 formed of a resin, and examples of the resin include an acrylic-modified epoxy resin. The solder resist 6 is provided with an opening for electrically connecting 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.

[0019] In a wiring board 1 according to one embodiment, at least a portion of the wiring conductor 4 includes a first pair of conductors 411 and a second pair of conductors 412 that extend adjacent to each other, as shown in Figure 2. Figure 2 is a schematic explanatory diagram showing one embodiment regarding the arrangement of land conductors 4a and via hole conductors 4b in the region X shown in Figure 1. In Figure 2, the insulating layer 3 is omitted. The first pair of conductors 411 and the second pair of conductors 412 are, for example, signal conductors.

[0020] The first pair of conductors 411 and the second pair of conductors 412 each include two line conductors 4'. The line conductors 4' are located adjacent to each other and function as a differential line, for example, with two line conductors 4'. The line conductors 4' have 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 top to the bottom surface of the insulating layer 3 and connecting with the land conductors 4a. The via hole conductors 4b may be filled within the via holes or may be located only on the inner wall surface of the via holes.

[0021] The first pair of conductors 411 includes a plurality of first via hole conductors 4b1 from the via hole conductors 4b, and a first land conductor 4a1 and a second land conductor 4a2 from the land conductors 4a. The first land conductors 4a1 connect the first via hole conductors 4b1 that are positioned to overlap each other in a planar perspective view. The shape of the first land conductors 4a1 is not limited as long as it can connect to the first via hole conductors 4b1. The first land conductors 4a1 can have, for example, a circular shape, a quadrilateral shape (square shape), or other polygonal shapes. The first land conductors 4a1 may each have the same shape, different shapes, the same size, or different sizes.

[0022] The number of layers of the first via-hole conductors 4b1, which are positioned to overlap each other in a planar perspective view, may be, for example, two to five layers. With such a number of layers, the area occupied by the via-hole conductors 4b can be reduced, and the stress applied to the connection between the land conductor 4a and the via-hole conductors 4b can be efficiently relieved.

[0023] The second land conductor 4a2 has a shape that is longer 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 a planar perspective. In other words, 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 refers to any one direction along the surface of the insulating layer 3. In other words, the first direction D1 can also be said to be the direction of extension of an imaginary line connecting the centroid points of via hole conductors that are located at different positions and spaced apart in a top perspective. The shape of the second land conductor 4a2 is not limited as long as it is a shape that can connect the first via hole conductors 4b1 located on the upper and lower sides of the second land conductor 4a2 at spaced-apart positions. Examples of the shape of the second land conductor 4a2 include shapes having a major axis (long side) and a minor axis (short side), such as an oval or rectangular shape. The second land conductor 4a2 is positioned such that its major axis (long side) is parallel to the first direction. The second land conductors 4a2 may be the same shape, different shapes, the same size, or different sizes. The relative size of the dimensions of the second land conductor 4a2 in the direction perpendicular to the first direction D1 and the dimensions of the first land conductor 4a1 in the direction perpendicular to the first direction D1 is not considered.

[0024] The second pair of conductors 412 includes multiple second via hole conductors 4b2 from the via hole conductors 4b, and a third land conductor 4a3 and a fourth land conductor 4a4 from the land conductors 4a. The third land conductor 4a3 connects the second via hole conductors 4b2 that are positioned to overlap each other in a planar perspective view. The shape of the third land conductor 4a3 is not limited as long as it can connect to the second via hole conductors 4b2. The shape of the third land conductor 4a3 is the same as that of the first land conductor 4a1, for example, a polygon such as a circle or a square. The third land conductors 4a3 may each have the same shape, different shapes, the same size, or different sizes.

[0025] The number of layers of the second via hole conductors 4b2, which are positioned to overlap each other in a planar perspective view, may be the same as the number of layers of the first via hole conductor 4b1, for example, two to five layers. With such a number of layers, the area to be arranged for the via hole conductors 4b can be reduced, and the stress applied to the connection between the land conductor 4a and the via hole conductors 4b can be efficiently relieved.

[0026] The fourth land conductor 4a4 has a shape that is longer 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 a planar perspective view. In other words, the dimension of the fourth land conductor 4a4 in the first direction D1 is larger than the dimension of the third land conductor 4a3 in the first direction D1. The first direction D1 is as described above. The shape of the fourth land conductor 4a4 is not limited as long as it is a shape that can connect the second via hole conductors 4b2 located on the upper and lower sides of the fourth land conductor 4a4 at spaced apart from each other. Examples of the shape of the fourth land conductor 4a4 include shapes having a major axis (long side) and a minor axis (short side), such as an oval or rectangular shape. The fourth land conductor 4a4 is positioned so that its major axis (long side) is approximately parallel to the first direction D1. The fourth land conductors 4a4 may each have the same shape, different shapes, the same size, or different sizes. The relative size of 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 is not considered.

[0027] In a wiring board 1 according to one embodiment, the second land conductor 4a2 and the fourth land conductor 4a4 are located between different layers of a 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 of conductors 411 and the second pair of conductors 412 is reduced. As a result, the risk of malfunction due to the mutual mixing of noise between differential lines can be reduced.

[0028] 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 multiple insulating layers 3. The second land conductor 4a2 may, for example, be located in the insulating layer 3 one layer above or one layer below the insulating layer 3 in which the fourth land conductor 4a4 is located. In Figure 2, the second land conductor 4a2 is located in the insulating layer 3 one layer below the insulating layer 3 in which the fourth land conductor 4a4 is located. In Figure 2, the insulating layers 3 are omitted as described above.

[0029] Alternatively, as shown in Figure 3, the second land conductor 4a2 may be located in an insulating layer 3 three layers below the insulating layer 3 on which the fourth land conductor 4a4 is located. That is, the second land conductor 4a2 may be located, for example, in an insulating layer 3 one to three layers above or one to three layers below the insulating layer 3 on which the fourth land conductor 4a4 is located. Figure 3 is a schematic explanatory diagram showing another embodiment regarding the arrangement of the land conductor 4a and via hole conductor 4b in the region X shown in Figure 1. In Figure 3, the insulating layer 3 is omitted.

[0030] The second land conductor 4a2 is located in an insulating layer 3 one to three layers above or one to three layers below the insulating layer 3 on which the fourth land conductor 4a4 is located, thereby further reducing the capacitance between the first pair of conductors 411 and the second pair of conductors 412. In particular, the second land conductor 4a2 is located in an insulating layer 3 one to three layers above or one to three layers below the insulating layer 3 on which the fourth land conductor 4a4 is located, thereby exhibiting an excellent suppression effect against the increase in capacitance.

[0031] In Figures 2 and 3, the first pair of conductors 411 and the second pair of conductors 412 are adjacent to each other in a direction along the direction in which the via hole conductors 4b of each of the two transmission lines 4' are aligned. That is, in Figures 2 and 3, the major axis of the second land conductor 4a2 and the major axis of the fourth land conductor 4a4 are located in a direction along the linear transmission lines 4' of the first pair of conductors 411 and the second pair of conductors 412, respectively. In Figures 2 and 3, "first direction D1" is the direction along the linear transmission lines 4' of the first pair of conductors 411 and the second pair of conductors 412. The fact that the first pair of conductors 411 and the second pair of conductors 412 are adjacent to each other in a direction along the direction in which the via hole conductors 4b of each of the two transmission lines are aligned facilitates matching the phase difference of signals propagating through the two transmission lines.

[0032] As shown in Figures 4 and 5, the first pair of conductors 411 and the second pair of conductors 412 may be adjacent to each other in a direction that intersects with the direction in which the via hole conductors 4b of each of the two line conductors 4' are aligned. That is, in Figures 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 a direction that intersects with the first pair of conductors 411 and the second pair of conductors 412, respectively. In Figures 4 and 5, "first direction D1" is the direction that intersects with the first pair of conductors 411 and the second pair of conductors 412. Figures 4 and 5 are schematic explanatory diagrams illustrating yet another embodiment regarding the arrangement of land conductors 4a and via hole conductors 4b in region X shown in Figure 1.

[0033] In Figure 4, the second land conductor 4a2 is located in the insulating layer 3 one layer below the insulating layer 3 where the fourth land conductor 4a4 is located. In Figure 5, the second land conductor 4a2 is located in the insulating layer 3 three layers below the insulating layer 3 where the fourth land conductor 4a4 is located. In Figures 4 and 5, the insulating layer 3 is omitted. The first pair of conductors 411 and the second pair of conductors 412 are adjacent to each other in a direction that intersects with the direction in which the via-hole conductors 4b of each of the two lines are aligned, allowing the first pair of conductors 411 and the second pair of conductors 412 to be arranged more closely together.

[0034] The mounting structure according to this disclosure includes a wiring board 1 according to one embodiment and an electronic component 8 located on the surface of the wiring board 1. The wiring conductors 4 (pads) in the openings of the solder resist 6 and the electrodes of the electronic component 8 are connected via solder 7. Examples of the electronic component 8 include semiconductor integrated circuit elements and optoelectronic elements, as described above. The electronic component 8 may be located on both sides of the wiring board 1, or the electronic component 8 may be located on one surface and, for example, a motherboard on the other surface.

[0035] The wiring board according to this disclosure is not limited to the embodiments described above. In the wiring board 1 described above, six layers of wiring conductors 4 are laminated in the laminated portion 5. However, the number of laminated wiring conductors 4 may be less than six and more than six. Furthermore, depending on the number of laminated wiring conductors 4, there may be two or more second land conductors 4a2 and fourth land conductors 4a4 provided on one line conductor 4'.

[0036] Specifically, in Figure 2, one line conductor 4' constituting the first pair of conductors 411 has a second land conductor 4a2 in the third layer from the bottom of the land conductor 4a. If the number of layers of wiring conductors 4 is even greater, for example, a second land conductor 4a2 may be provided in the sixth layer from the bottom of the land conductor 4a. In other words, if the number of layers of wiring conductors 4 is large, multiple second land conductors 4a2 may be provided, for example, every 2 to 5 layers. The same applies to the fourth land conductor 4a4. [Explanation of symbols]

[0037] 1 Wiring board 2 Core Layers 3. Insulating layer 4 Wiring conductors 411 First pair of conductors 412 Second pair of conductors 4' Track conductor 4a Land conductor 4a1 First land conductor 4a2 Second Land Conductor 4a3 Third Land Conductor 4a4 4th Land Conductor 4b Via hole conductor 4b1 First via hole conductor 4b2 Second via hole conductor 5. Laminated section 6 Solder Resist 7 Handa 8 Electronic Components 10 Implementation Structure

Claims

1. The laminated portion comprises a plurality of insulating layers stacked on top of 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 of conductors and a second pair of conductors, each containing two line conductors located adjacent to each other. The first pair of conductors and the second pair of conductors extend adjacent to each other at a distance greater than the distance between the two line conductors. Each of the two line conductors 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 positioned to overlap each other in a planar perspective view. The second land conductor has a shape that is longer in the first direction than the first land conductor, and connects the first via hole conductors that are spaced apart from each other along the first direction in a planar perspective view. The third land conductor connects the second via hole conductors that are positioned to overlap each other in a planar perspective view. The fourth land conductor has a shape that is longer in the first direction than the third land conductor, and connects the second via hole conductors which are spaced apart from each other along the first direction in a planar perspective view. The second land conductor and the fourth land conductor are located between different layers of the plurality of insulating layers. Wiring board.

2. The wiring board according to claim 1, wherein the first pair of conductors and the second pair of conductors are spaced apart from each other in a direction along the direction in which the via-hole conductors of the two line conductors are aligned.

3. The wiring board according to claim 1, wherein the first pair of conductors and the second pair of conductors are spaced apart from each other in a direction that intersects with the direction in which the via-hole conductors of the two line conductors are aligned.

4. The wiring board according to claim 1, wherein the second land conductor of the first pair of conductors and the fourth land conductor of the second pair of conductors are spaced apart from each other, and the second land conductor is located in the insulating layer one level above or one level below the insulating layer on which the fourth land conductor is located.

5. The wiring board according to claim 1, wherein the number of stacked via-hole conductors that are positioned to overlap each other in a planar perspective view is two or more and five or less.

6. The wiring board according to claim 1, wherein the first pair of conductors and the second pair of conductors are signal conductors.

7. A mounting structure comprising a wiring board according to any one of claims 1 to 6 and an electronic component located in the mounting area of ​​the wiring board.

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