Substrate connection body

Abstract

This substrate connection body includes: a first circuit board having first wiring; and a second circuit board having second wiring. The first wiring has a first terminal. The second wiring has a second terminal. The surface of the first terminal faces the surface of the second terminal.

Description

Board connector

[0001] The present disclosure relates to a substrate connector. This application claims priority from Japanese Patent Application No. 2024-116047, filed on July 19, 2024. The entire contents of the Japanese patent application are incorporated herein by reference.

[0002] Japanese Patent Laid-Open Publication No. 2022-151716 (Patent Document 1) describes a circuit board, which includes a dielectric layer and a signal line disposed on the dielectric layer.

[0003] Japanese Patent Application Laid-Open No. 2022-151716

[0004] A substrate connection body according to the present disclosure includes a first circuit board having a first wiring and a second circuit board having a second wiring. The first wiring has a first terminal. The second wiring has a second terminal. A surface of the first terminal faces a surface of the second terminal.

[0005] FIG. 1 is a plan view of substrate connection body 100. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is an enlarged view of line III in FIG. 2. FIG. 4 is a plan view of circuit board 10 used in substrate connection body 100. FIG. 5 is a plan view of circuit board 20 used in substrate connection body 100. FIG. 6 is a plan view of circuit board 40. FIG. 7 is a cross-sectional view of substrate connection body 100 according to a modified example. FIG. 8 is a plan view of substrate connection body 200. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 10 is an enlarged view of line X in FIG. 9. FIG. 11A is a simulation result showing the relationship between the frequency of a signal flowing through a wiring in circuit board 40 and the insertion loss of circuit board 40. FIG. 11B is a simulation result showing the relationship between the frequency of a signal flowing through a wiring in substrate connection body 200 and the insertion loss of substrate connection body 200. FIG. 12A is a simulation result showing the relationship between the frequency of a signal flowing through a wiring in circuit board 40 and the reflection loss of circuit board 40. FIG. 12B shows the results of a simulation showing the relationship between the frequency of a signal flowing through the wiring in substrate connection body 200 and the return loss of substrate connection body 200. In FIG.

[0006] [Problem to be Solved by the Present Disclosure] To increase the wiring length, the circuit board described in Patent Document 1 is formed long in the direction in which the signal lines extend. However, in this case, there are constraints on the manufacturing process. More specifically, exposure is difficult when forming a resist pattern used to pattern the signal lines.

[0007] The present disclosure has been made in view of the above-mentioned problems of the conventional art. More specifically, the present disclosure provides a board connector that can connect circuit boards with little loss.

[0008] [Advantages of the Present Disclosure] The board connector of the present disclosure allows connection between circuit boards with little loss.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) The substrate connection body according to this embodiment includes a first circuit board having a first wiring and a second circuit board having a second wiring. The first wiring has a first terminal. The second wiring has a second terminal. The surface of the first terminal faces the surface of the second terminal. The substrate connection body of (1) enables connection between circuit boards with little loss.

[0011] (2) In the substrate connector of (1), the distance between the surface of the first terminal and the surface of the second terminal may be 10 μm or less.

[0012] (3) In the substrate connection body of (1) or (2), the surface of the first terminal may be pressure-welded to the surface of the second terminal.

[0013] (4) The substrate connection body of any one of (1) to (3) may further include a resin layer. The resin layer may cover the surface and side surfaces of the first terminal and the second terminal.

[0014] (5) The substrate connection body of (1) or (2) may further include a resin layer and metal particles contained in the resin layer. The resin layer may cover the surface and side surface of the first terminal and the surface and side surface of the second terminal. The metal particles may be sandwiched between the surface of the first terminal and the surface of the second terminal.

[0015] (6) In the substrate connection assembly of (1) to (5), the first circuit board may have a first insulating layer. The second circuit board may have a second insulating layer. The first wiring may be disposed on the first insulating layer. The second wiring may be disposed on the second insulating layer. The second insulating layer may be formed of a material different from that of the first insulating layer.

[0016] (7) In the substrate connection body of any one of (1) to (5), the first wiring and the second wiring may be high-frequency signal wiring.

[0017] (8) In the substrate connection body of (1) to (5), the first wiring and the second wiring may be power supply wiring.

[0018] (9) In the substrate connection bodies of (1) to (5), the width of the first terminal and the width of the second terminal may be different from each other.

[0019] [Details of the embodiment of the present disclosure] Next, details of the embodiment of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and redundant description will not be repeated.

[0020] First Embodiment A substrate connection body (substrate connection body 100) according to a first embodiment will be described.

[0021] <Configuration of substrate connection body 100> Fig. 1 is a plan view of substrate connection body 100. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is an enlarged view taken along line III in Fig. 2. Fig. 4 is a plan view of circuit board 10 used in substrate connection body 100. Fig. 5 is a plan view of circuit board 20 used in substrate connection body 100. As shown in Figs. 1 to 5, substrate connection body 100 has circuit board 10, circuit board 20, and resin layer 30.

[0022] The circuit board 10 includes an insulating layer 11 , a wiring 12 , a wiring 13 , a ground pattern 14 , and a ground pattern 15 .

[0023] The insulating layer 11 has a principal surface 11a and a principal surface 11b. The principal surface 11b is the surface opposite to the principal surface 11a. The principal surface 11a and the principal surface 11b are end surfaces of the insulating layer 11 in the thickness direction.

[0024] In the following, a planar view refers to a case where the substrate connection body 100 is viewed along the normal direction to the main surface 11 a. In the following, a first direction DR1 is one of the directions in a planar view, a second direction DR2 is a direction perpendicular to the first direction DR1 in a planar view, and a third direction DR3 is a direction perpendicular to the first direction DR1 and the second direction DR2. The third direction DR3 is the normal direction to the main surface 11 b.

[0025] The wiring 12 and the wiring 13 are disposed on the insulating layer 11, more specifically on the main surface 11a. The wiring 12 and the wiring 13 each extend along a first direction DR1. The wiring 12 and the wiring 13 are arranged at an interval along a second direction DR2. The wiring 12 has a terminal 12a at its end in the first direction DR1, and the wiring 13 has a terminal 13a at its end in the first direction DR1. The terminals 12a and 13a are arranged at an interval along the second direction DR2.

[0026] The width of the wiring 12 in the second direction DR2 is defined as width W1. However, the width of the terminal 12a in the second direction DR2 is width W2. Width W2 is smaller than width W1. The width of the wiring 13 in the second direction DR2 is defined as width W3. However, the width of the terminal 13a in the second direction DR2 is width W4. Width W4 is smaller than width W3.

[0027] The ground pattern 14 is disposed on the insulating layer 11, more specifically on the main surface 11a. In a plan view, the ground pattern 14 surrounds the wiring 12 and the wiring 13 at a distance. The ground pattern 15 is disposed on the insulating layer 11, more specifically on the main surface 11b. A ground potential is applied to the ground patterns 14 and 15.

[0028] The insulating layer 11 is made of an electrically insulating material, such as a fluororesin. The wiring 12, the wiring 13, the ground pattern 14, and the ground pattern 15 are made of a conductive material, such as copper or a copper alloy.

[0029] The circuit board 20 includes an insulating layer 21 , a wiring 22 , a wiring 23 , a ground pattern 24 , and a ground pattern 25 .

[0030] The insulating layer 21 has a principal surface 21 a and a principal surface 21 b. The principal surface 21 b is the surface opposite to the principal surface 21 a. The principal surfaces 21 a and 21 b are end surfaces of the insulating layer 21 in the thickness direction.

[0031] The wiring 22 and the wiring 23 are disposed on the insulating layer 21, more specifically on the main surface 21a. The wiring 22 and the wiring 23 each extend along the first direction DR1. The wiring 22 and the wiring 23 are arranged at an interval along the second direction DR2. The wiring 22 has a terminal 22a at its end in the first direction DR1, and the wiring 23 has a terminal 23a at its end in the first direction DR1. The terminals 22a and 23a are arranged at an interval along the second direction DR2.

[0032] The width of the wiring 22 in the second direction DR2 is width W5. However, the width of the terminal 22a in the second direction DR2 is width W6. Width W6 is smaller than width W5. The width of the wiring 23 in the second direction DR2 is width W7. However, the width of the terminal 23a in the second direction DR2 is width W8. Width W8 is smaller than width W7. Widths W1 and W5 are, for example, equal to each other. Widths W2 and W6 are, for example, equal to each other. Widths W3 and W7 are, for example, equal to each other. Widths W4 and W8 are, for example, equal to each other.

[0033] The ground pattern 24 is disposed on the insulating layer 21, more specifically on the main surface 21a. In a plan view, the ground pattern 24 surrounds the wiring 22 and the wiring 23 at a distance. The ground pattern 25 is disposed on the insulating layer 21, more specifically on the main surface 21b. A ground potential is applied to the ground patterns 24 and 25.

[0034] The insulating layer 21 is made of an electrically insulating material, such as a fluororesin. The wiring 22, the wiring 23, the ground pattern 24, and the ground pattern 25 are made of a conductive material, such as copper or a copper alloy.

[0035] The circuit boards 10 and 20 are arranged to partially overlap each other such that an end of the circuit board 10 in the first direction DR1 faces an end of the circuit board 20 in the first direction DR1. More specifically, the circuit boards 10 and 20 are arranged to partially overlap each other such that the surfaces of the terminals 12a and 13a face the surfaces of the terminals 22a and 23a, respectively.

[0036] The distance between the surface of terminal 12a and the surface of terminal 22a in the third direction DR3 is defined as distance DIS1, and the distance between the surface of terminal 13a and the surface of terminal 23a in the third direction DR3 is defined as distance DIS2. Distances DIS1 and DIS2 are, for example, 10 μm or less.

[0037] A resin layer 30 is interposed between the circuit board 10 and the circuit board 20. That is, the resin layer 30 covers the surfaces and side surfaces of the terminals 12a, 13a, 22a, and 23a. The resin layer 30 is made of, for example, epoxy resin.

[0038] No metal particles are contained in the resin layer 30. In other words, the resin layer 30 is formed of an NCF (Non-Conductive Film).

[0039] 2 and 3, a resin layer 30 is interposed between the surface of terminal 12a and the surface of terminal 22a, and a resin layer 30 is interposed between the surface of terminal 13a and the surface of terminal 23a. Even in such a case, if the surfaces of terminals 12a and 22a are closely arranged and the surfaces of terminals 13a and 23a are closely arranged (specifically, if the distances DIS1 and DIS2 are 10 μm or less), high-frequency signals can be transmitted between the terminals even when the pressure welding is performed with only the resin layer 30 interposed. Of course, the surface of terminal 12a may be in contact with the surface of terminal 22a, and the surface of terminal 13a may be in contact with the surface of terminal 23a.

[0040] <Method for Manufacturing Substrate-Connected Body 100> The method for manufacturing substrate-connected body 100 includes a circuit board forming step and a circuit board connecting step.

[0041] In the circuit board forming process, the circuit board 10 is formed. In the circuit board forming process, first, an insulating layer 11 is prepared. At this stage, conductor layers are formed on the main surface 11a and the main surface 11b. Second, a resist pattern is formed on the conductor layer on the main surface 11a. The resist pattern is formed, for example, by forming a dry film resist on the conductor layer and then exposing and developing the dry film resist. Third, the conductor layer on the main surface 11a is etched using the resist pattern as a mask. By this etching, the conductor layer on the main surface 11a is patterned into wiring 12, wiring 13, and ground pattern 14. Note that the conductor layer on the main surface 11b becomes the ground pattern 15 as is. In the circuit board forming process, a circuit board 20 is also formed using a similar method.

[0042] In the circuit board connecting process, the circuit board 10 and the circuit board 20 are connected. In the circuit board connecting process, first, the circuit board 10 and the circuit board 20 are arranged opposite each other with the resin layer 30 interposed therebetween so that the surfaces of the terminals 12a and 13a face the surfaces of the terminals 22a and 23a, respectively. At this stage, the resin layer 30 is uncured. Second, the overlapping portions of the circuit board 10 and the circuit board 20 are heated while being pressurized. As a result, the surfaces of the terminals 12a and 13a are electrically connected to the surfaces of the terminals 22a and 23a, respectively, and the resin layer 30 is cured, mechanically connecting the circuit board 10 and the circuit board 20. As a result, the board connection body 100 having the structure shown in FIGS. 1 to 3 is formed.

[0043] <Effects of the Substrate Connection Body 100> In the substrate connection body 100, the circuit board 10 and the circuit board 20 are connected, thereby enabling the wiring length to be extended. FIG. 6 is a plan view of the circuit board 40. As shown in FIG. 6, the circuit board 40 includes an insulating layer 41 and wiring 42, wiring 43, and a ground pattern 44 disposed on the insulating layer 41. The wiring 42 and wiring 43 each extend along the first direction DR1. The wiring 42 and wiring 43 are arranged at intervals along the second direction DR2. The ground pattern 44 surrounds the wiring 42 and wiring 43 at an interval in plan view. Note that a ground pattern (not shown) is disposed on the surface of the insulating layer 41 opposite the wiring 42, wiring 43, and ground pattern 44. In the first direction DR1, the length of the circuit board 40 is greater than the length of the circuit board 10 and the length of the circuit board 20. In this way, by using the circuit board 40 formed long along the first direction DR1 instead of the board connection body 100, it is also possible to extend the wiring length.

[0044] As described above, the patterning of the wiring 42 and the wiring 43 is performed by etching using a resist pattern formed on the conductor layer as a mask, and the resist pattern is formed by exposing and developing a dry film resist, for example. However, if the length of the circuit board 40 in the first direction DR1 is large (if the length of the wiring 42 and the wiring 43 in the first direction DR1 is large), the above exposure becomes difficult, and as a result, it becomes difficult to form the circuit board 40.

[0045] In the substrate connection body 100, the wiring length is extended by connecting the circuit boards 10 and 20 to each other, so the above-mentioned difficulty of exposure is not present. Furthermore, in the substrate connection body 100, the surface of the terminal 12a and the surface of the terminal 22a are arranged opposite each other, and the surface of the terminal 13a and the surface of the terminal 23a are arranged opposite each other, so that the circuit boards 10 and 20 are electrically connected, and loss between the circuit boards is small. In this way, the substrate connection body 100 makes it possible to connect the circuit boards with small loss and obtain long wiring lengths.

[0046] <Modifications> In the above example, the wiring 12, wiring 13, wiring 22, and wiring 23 are signal wiring, but the wiring on circuit board 10 and circuit board 20 may be power wiring instead of signal wiring. Furthermore, in the above example, the insulating layer 11 and insulating layer 21 are formed of fluororesin, i.e., the circuit board 10 and circuit board 20 are flexible substrates, but one of circuit board 10 and circuit board 20 may be a rigid substrate (the insulating layer of one of the circuit boards may be formed of, for example, glass epoxy). In the above example, the case where two circuit boards are connected is described, but in substrate connection body 100, three or more circuit boards may be connected along first direction DR1 in a similar manner.

[0047] Fig. 7 is a cross-sectional view of a substrate connection body 100 according to a modified example. As shown in Fig. 7, the width W2 may be different from the width W6, and the width W4 may be different from the width W8. In the example shown in Fig. 7, the width W2 is larger than the width W6, and the width W4 is larger than the width W8, but this example is not limiting. For example, the width W2 may be smaller than the width W6, and the width W4 may be smaller than the width W8. Alternatively, the width W2 may be larger than the width W6, while the width W4 may be smaller than the width W8.

[0048] If the arrangement of the circuit board 20 is shifted along the second direction DR2, the overlap width between the terminals 12a and 22a in the second direction DR2 and the overlap width between the terminals 13a and 23a in the second direction DR2 change, resulting in increased impedance mismatch at the connection between the wiring 12 and the wiring 22 and the connection between the wiring 13 and the wiring 23. As a result, reflection loss increases. In this regard, if the width W2 is different from the width W6 and the width W4 is different from the width W8, the overlap width between the terminals 12a and 22a in the second direction DR2 and the overlap width between the terminals 13a and 23a in the second direction DR2 can be kept constant even if the arrangement of the circuit board 20 is shifted along the second direction DR2. Therefore, in this case, reflection loss can be further reduced.

[0049] Second Embodiment A substrate connection body (substrate connection body 200) according to a second embodiment will be described below. Here, differences from substrate connection body 100 will be mainly described, and overlapping descriptions will not be repeated.

[0050] <Configuration of substrate connection body 200> Fig. 8 is a plan view of substrate connection body 200. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Fig. 10 is an enlarged view taken along line X in Fig. 9. As shown in Figs. 8 to 10, substrate connection body 200 has circuit board 10, circuit board 20, and resin layer 30. In this regard, the configuration of substrate connection body 200 is common to the configuration of substrate connection body 100.

[0051] In substrate connection body 200, a plurality of metal particles 31 are contained in resin layer 30. That is, in substrate connection body 200, resin layer 30 is an ACF (Anisotropic-Conductive Film). Some of the plurality of metal particles 31 are sandwiched between the surfaces of terminals 12a and 22a and between the surfaces of terminals 13a and 23a.

[0052] An insulating film is formed on the surface of the metal particles 31. When the metal particles 31 are sandwiched between the surface of the terminal 12a and the surface of the terminal 22a and between the surface of the terminal 13a and the surface of the terminal 23a, the insulating film on the surface of the metal particles 31 is destroyed, and the metal particles 31 electrically connect between the surface of the terminal 12a and the surface of the terminal 22a and between the surface of the terminal 13a and the surface of the terminal 23a. On the other hand, the insulating film on the surface of the metal particles 31 that are not sandwiched between the surface of the terminal 12a and the surface of the terminal 22a and the surface of the terminal 13a and the surface of the terminal 23a is not destroyed, so insulation between adjacent terminals is ensured. In these respects, the configuration of the substrate connection body 200 differs from the configuration of the substrate connection body 100.

[0053] <Effects of Substrate Connection Body 200> As with substrate connection body 100, substrate connection body 200 can also connect circuit boards with small loss and achieve long wiring lengths.

[0054] 11A shows simulation results illustrating the relationship between the frequency of a signal flowing through the wiring in circuit board 40 and the transmission loss of circuit board 40. FIG. 11B shows simulation results illustrating the relationship between the frequency of a signal flowing through the wiring in substrate connection body 200 and the transmission loss of substrate connection body 200. In FIGS. 11A and 11B, the height of the wiring was set to 32 μm, the thickness of the insulating layer was set to 113 μm, the spacing between adjacent wiring was set to 85 μm, the spacing between adjacent terminals was set to 150 μm, the width of the wiring was set to 165 μm, and the width of the terminal was set to 100 μm. As shown in FIGS. 11A and 11B, there was no significant difference between the transmission loss of circuit board 40 and the transmission loss of substrate connection body 200.

[0055] 12A shows simulation results illustrating the relationship between the frequency of a signal flowing through the wiring in circuit board 40 and the reflection loss of circuit board 40. FIG. 12B shows simulation results illustrating the relationship between the frequency of a signal flowing through the wiring in substrate connection body 200 and the reflection loss of substrate connection body 200. In FIGS. 12A and 12B , the height of the wiring was set to 32 μm, the thickness of the insulating layer was set to 113 μm, the spacing between adjacent wiring was set to 85 μm, the spacing between adjacent terminals was set to 150 μm, the width of the wiring was set to 165 μm, and the width of the terminals was set to 100 μm. As shown in FIGS. 12A and 12B , there was no significant difference between the reflection loss of circuit board 40 and the reflection loss of substrate connection body 200.

[0056] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the above-described embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0057] 10 Circuit board, 11 Insulating layer, 11a, 11b Main surface, 12, 13 Wiring, 12a, 13a Terminal, 14, 15 Ground pattern, 20 Circuit board, 21 Insulating layer, 21a Main surface, 21b Main surface, 22, 23 Wiring, 22a, 23a Terminal, 24, 25 Ground pattern, 30 Resin layer, 31 Metal particles, 40 Circuit board, 41 Insulating layer, 42, 43 Wiring, 44 Ground pattern, 100, 200 Substrate connection body, DIS1, DIS2 Distance, DR1 First direction, DR2 Second direction, DR3 Third direction, W1, W2, W3, W4, W5, W6, W7, W8 Width.

Claims

1. A substrate connector comprising: a first circuit board having a first wiring; and a second circuit board having a second wiring, wherein the first wiring has a first terminal; the second wiring has a second terminal; and a surface of the first terminal faces a surface of the second terminal.

2. The substrate connection body according to claim 1, wherein the distance between the surface of the first terminal and the surface of the second terminal is 10 μm or less.

3. A board connection body according to claim 1 or claim 2, wherein the surface of the first terminal is pressure-welded to the surface of the second terminal.

4. A substrate connection body according to any one of claims 1 to 3, further comprising a resin layer, the resin layer covering the surface and side surfaces of the first terminal and the second terminal.

5. A substrate connection body as described in claim 1 or claim 2, further comprising a resin layer and metal particles contained in the resin layer, wherein the resin layer covers the surface and side surfaces of the first terminal and also covers the surface and side surfaces of the second terminal, and the metal particles are sandwiched between the surface of the first terminal and the surface of the second terminal.

6. A substrate connection body according to any one of claims 1 to 5, wherein the first circuit board has a first insulating layer, the second circuit board has a second insulating layer, the first wiring is disposed on the first insulating layer, the second wiring is disposed on the second insulating layer, and the second insulating layer is formed of a material different from that of the first insulating layer.

7. A substrate connection body according to any one of claims 1 to 5, wherein the first wiring and the second wiring are high-frequency signal wiring.

8. A substrate connection body according to any one of claims 1 to 5, wherein the first wiring and the second wiring are power supply wiring.

9. A substrate connection body according to any one of claims 1 to 5, wherein the width of the first terminal and the width of the second terminal are different from each other.

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