JP2017208371A - Circuit board, manufacturing method of circuit board, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board which has flexibility and excellent signal transmission characteristics.SOLUTION: A circuit board 1 includes a flexible substrate 10 and a flexible substrate 20. The flexible substrate 10 has: a base layer 11; and signal wiring 12 provided on a surface 11a of the base layer 11 and extends in a direction S. The flexible substrate 20 is provided such that it faces the surface 11a. The flexible substrate 10 is bonded to the flexible substrate 20 via a bonding layer 30 interposed at an end 2 of the flexible substrates. A chip capacitor 40 mounted on the signal wiring 12 on the flexible substrate 10 is interposed in a non-bonded portion 3 between the flexible substrate 10 and the flexible substrate 20.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a circuit board, a circuit board manufacturing method, and an electronic apparatus.

  A flexible substrate in which wiring is provided on an insulating layer such as polyimide, and a circuit substrate (multilayer flexible circuit substrate) in which such a group of flexible substrates are joined and bonded using an adhesive are known.

  With respect to such a circuit board, for example, a flexible board group is joined using an adhesive so that a space (non-joined part) is formed between them, and is disconnected due to flexibility or flexibility and repeated bending. A technique for increasing the resistance to is known.

JP 2007-59822 A

  In a circuit board in which a space portion as described above is provided between flexible substrates to be bonded using an adhesive, the distance between the flexible substrates can change in the space portion when it is bent. A change in the distance between the flexible boards that occurs when bent can cause a change in the distance between the wirings provided on the flexible boards, which can degrade the signal transmission characteristics of the circuit board.

  According to an aspect of the present invention, a first flexible substrate having a first insulating layer and a first signal wiring provided on a first surface of the first insulating layer and extending in a first direction; A second flexible substrate facing one surface, an adhesive layer interposed in a first region between the first flexible substrate and the second flexible substrate, and the first flexible substrate and the second flexible substrate. There is provided a circuit board including a first electronic component that is interposed in a second region different from the first region therebetween and mounted on the first signal wiring.

  In addition, according to one aspect of the present invention, a method for manufacturing a circuit board as described above and an electronic device including the circuit board as described above are provided.

  According to the disclosed technology, the distance between the flexible boards that are partially bonded via the adhesive layer is ensured by the intervening electronic components, has flexibility, and has excellent signal transmission characteristics. Is realized. In addition, an electronic device including such a circuit board is realized.

It is a figure which shows an example of a circuit board. It is a figure which shows another example of a circuit board. It is a figure which shows an example of the bent circuit board. It is a figure (the 1) which shows the mode of the non-bonding part of a circuit board. It is FIG. (2) which shows the mode of the non-bonding part of a circuit board. It is a figure which shows an example of the circuit board which concerns on 1st Embodiment. It is a figure which shows a mode when the circuit board which concerns on 1st Embodiment is bent. It is a figure which shows an example of the signal transmission characteristic of a circuit board. It is a figure which shows another example of the circuit board which concerns on 1st Embodiment. It is a figure (the 1) which shows an example of the formation method of the circuit board which concerns on 1st Embodiment. It is FIG. (2) which shows an example of the formation method of the circuit board which concerns on 1st Embodiment. It is a figure which shows an example of the circuit board which concerns on 2nd Embodiment. It is a figure which shows another example of the circuit board based on 2nd Embodiment. It is a figure which shows another example of the circuit board based on 2nd Embodiment. It is a figure which shows an example of the circuit board which concerns on 3rd Embodiment. It is a figure which shows an example of the circuit board which concerns on 4th Embodiment. It is a figure which shows an example of the formation method of the circuit board which concerns on 4th Embodiment. It is a figure which shows another example of the circuit board which concerns on 4th Embodiment. It is a figure which shows another example of the formation method of the circuit board which concerns on 4th Embodiment. It is a figure which shows an example of the electronic device which concerns on 5th Embodiment. It is a figure which shows an example of the electronic device which concerns on 6th Embodiment.

First, a configuration example of a circuit board (multilayer flexible circuit board) including a group of stacked flexible boards (Flexible Printed Circuit (s); FPC) will be described.
FIG. 1 is a diagram illustrating an example of a circuit board. FIG. 1 schematically shows a cross section of an essential part of an example of a circuit board.

A circuit board 300A shown in FIG. 1 includes a flexible board 310 and a flexible board 320, and an adhesive layer 330 interposed therebetween.
The flexible substrate 310 includes a base layer 311, a wiring 312 provided on one surface 311 a of the base layer 311, and a wiring 313 provided on the other surface 311 b of the base layer 311. For the base layer 311, for example, a resin material such as polyimide is used. A metal material such as copper (Cu) is used for the wiring 312 and the wiring 313. For example, one of the wiring 312 and the wiring 313 is a signal wiring and the other is a ground (GND) wiring. The flexible substrate 310 further includes a cover lay layer 314 provided on one surface 311 a of the base layer 311 and covering the wiring 312, and a cover lay layer 315 provided on the other surface 311 b of the base layer 311 and covering the wiring 313. Have. For the coverlay layer 314 and the coverlay layer 315, for example, a resin material such as polyimide is used.

  The flexible substrate 320 has the same configuration as the flexible substrate 310. That is, the flexible substrate 320 includes a base layer 321, a wiring 322 provided on one surface 321 a of the base layer 321, and a wiring 323 provided on the other surface 321 b of the base layer 321. For the base layer 321, for example, a resin material such as polyimide is used. A metal material such as Cu is used for the wiring 322 and the wiring 323. For example, one of the wiring 322 and the wiring 323 is a signal wiring and the other is a GND wiring. The flexible substrate 320 further includes a cover lay layer 324 provided on one surface 321a of the base layer 321 and covering the wiring 322, and a cover lay layer 325 provided on the other surface 321b of the base layer 321 and covering the wiring 323. Have. For the coverlay layer 324 and the coverlay layer 325, for example, a resin material such as polyimide is used.

  The adhesive layer 330 is interposed between the flexible substrate 310 and the flexible substrate 320 as described above, and adheres the flexible substrate 310 and the flexible substrate 320. A resin material such as polyimide resin or epoxy resin is used for the adhesive layer 330.

Like the circuit board 300 </ b> A shown in FIG. 1, for example, the flexible board 310 and the flexible board 320 are bonded and laminated together with an adhesive layer 330 as a whole.
Although FIG. 1 shows an example in which two flexible substrates 310 and 320 are bonded and stacked with an adhesive layer 330, a third flexible substrate may be bonded and stacked in the same manner. The same applies to the adhesion and lamination of the fourth and subsequent flexible substrates.

  However, if a method of totally bonding the laminated flexible boards as illustrated in FIG. 1 is used, the flexibility of the circuit board tends to be gradually lost as the number of the flexible boards laminated increases.

FIG. 2 is a diagram showing another example of the circuit board. FIG. 2 schematically shows a cross-section of the main part of another example of the circuit board.
The circuit board 300B shown in FIG. 2 is the circuit shown in FIG. 1 in that the flexible substrate 310 and the flexible substrate 320 are partially bonded and laminated at the end portions thereof with the adhesive layer 330. Different from the substrate 300A. In the circuit board 300B, a portion (non-adhesive portion) 340 that is not adhered by the adhesive layer 330 is a cavity. Thus, in the circuit board 300B, the adhesion region by the adhesion layer 330 is made partial.

  FIG. 2 shows an example in which the two flexible substrates 310 and the flexible substrate 320 are partially adhered and laminated by the adhesive layer 330, but the same applies to the adhesion and lamination of the third and subsequent flexible substrates. Can be done.

  When using the technique of partially bonding the laminated flexible substrates as illustrated in FIG. 2, the method is more flexible than using the technique of bonding the laminated flexible substrates as illustrated in FIG. Loss of flexibility of the circuit board can be suppressed even when the number of stacked boards increases.

  However, for example, as shown in FIG. 2, the following may occur in the circuit board 300 </ b> B that employs a technique in which the flexible substrate 310 and the flexible substrate 320 are partially adhered by the adhesive layer 330.

FIG. 3 is a diagram illustrating an example of a bent circuit board. FIG. 3 schematically shows a cross section of an essential part of an example of a bent circuit board.
In the circuit board 300B in which the flexible board 310 and the flexible board 320 are partially bonded by the adhesive layer 330, when the circuit board 300B is bent, as shown in FIG. The distance between the substrate 320 can vary. When the distance between the flexible board 310 and the flexible board 320 changes in this way, the distance D between the wiring 312 and the wiring 323 facing each other at the non-bonding portion 340 changes, resulting in the circuit board 300B. The signal transmission characteristics may change.

4 and 5 are views showing a state of the non-bonded portion of the circuit board.
4A and 4B, when one of the wirings of the flexible substrate facing each other is a signal wiring and the other is a GND wiring, the circuit board is not bent and is bent. A cross section of the non-adhered portion is schematically shown. 4A corresponds to the L1-L1 cross-sectional schematic diagram of FIG. 2, and FIG. 4B corresponds to the L2-L2 cross-sectional schematic diagram of FIG.

  For example, as shown in FIG. 4A, the flexible substrate 310 is provided with a signal wiring 312a as a wiring 312 on one surface 311a side of the base layer 311 and a GND wiring 313a as a wiring 313 on the other surface 311b side. Provided. The flexible substrate 320 is provided with a signal wiring 322a as a wiring 322 on one surface 321a side of the base layer 321 and a GND wiring 323a as a wiring 323 on the other surface 321b side. The flexible substrate 310 and the flexible substrate 320 are bonded and laminated so that the signal wiring 312a and the GND wiring 323a face each other.

  The impedance of the signal wiring 312a of the flexible substrate 310 is adjusted by, for example, the distance to the GND wiring 313a on the opposite side and the distance to the GND wiring 323a of the opposing flexible substrate 320. When the circuit board 300B is bent from the adjusted state before bending as shown in FIG. 4A and the signal wiring 312a and the GND wiring 323a approach each other at the non-bonding portion 340 as shown in FIG. 4B, impedance mismatching occurs. There is a risk of inviting.

  5A and 5B respectively show the non-bonded portion when the circuit board is not bent and when it is bent when both of the wirings of the flexible substrate facing each other are signal wirings. The cross section of is schematically shown. 5A corresponds to the L1-L1 cross-sectional schematic diagram of FIG. 2, and FIG. 5B corresponds to the L2-L2 cross-sectional schematic diagram of FIG.

  For example, as shown in FIG. 5A, the flexible substrate 310 is provided with a signal wiring 312b as a wiring 312 on one surface 311a side of the base layer 311 and a GND wiring 313b as a wiring 313 on the other surface 311b side. Provided. The flexible substrate 320 is provided with a GND wiring 322b as a wiring 322 on one surface 321a side of the base layer 321 and a signal wiring 323b as a wiring 323 on the other surface 321b side. The flexible substrate 310 and the flexible substrate 320 are bonded and laminated so that the signal wiring 312b and the signal wiring 323b face each other.

  In such a circuit board 300B, the circuit board 300B is bent from the state of FIG. 5A before bending, and the signal wiring 312b and the signal wiring 323b approach each other at the non-bonding portion 340 as shown in FIG. 5B. There is a risk of crosstalk.

  As described above, in the circuit board 300B in which the flexible substrates 310 and 320 are partially bonded with the adhesive layer 330, loss of flexibility due to the lamination can be suppressed, while the change in the distance between the wirings in the non-bonded portion 340 when bent. As a result, impedance mismatch and crosstalk may occur. Impedance mismatch and crosstalk are factors that degrade the signal transmission characteristics of the circuit board 300B.

  In view of the above points, here, a technique as described below as an embodiment is adopted to realize a circuit board having flexibility and excellent signal transmission characteristics. In addition, various electronic devices (electronic devices) including such a circuit board are realized.

First, the first embodiment will be described.
FIG. 6 is a diagram illustrating an example of a circuit board according to the first embodiment. FIG. 6 schematically illustrates a cross-section of the main part of an example of the circuit board according to the first embodiment.

A circuit board 1 shown in FIG. 6 includes a flexible board 10 and a flexible board 20, and an adhesive layer 30 interposed therebetween.
The flexible substrate 10 includes a base layer 11 that is a base insulating layer, a signal wiring 12 provided on one surface 11 a of the base layer 11, and a GND wiring 13 provided on the other surface 11 b of the base layer 11. Have. For example, the signal wiring 12 is provided as a line-shaped pattern extending in the direction S, and the GND wiring 13 is provided as a planar pattern including an area corresponding to the arrangement area of the signal wiring 12. The flexible substrate 10 is further provided with an insulating coverlay layer 14 (protective layer) provided on one surface 11a of the base layer 11 to cover the signal wiring 12, and provided on the other surface 11b of the base layer 11 with GND wiring. 13 and an insulating coverlay layer 15 (protective layer).

  Various insulating materials, for example, resin materials such as polyimide are used for the base layer 11. For the signal wiring 12 and the GND wiring 13, various conductor materials, for example, metal materials such as Cu are used. For the coverlay layer 14 and the coverlay layer 15, various insulating materials, for example, resin materials such as polyimide are used.

  On the signal wiring 12 of the flexible substrate 10, an electronic component, here, as an example, a chip capacitor 40 for AC coupling is mounted. A group of terminals 40b respectively connected to the group of electrodes 40a of the chip capacitor 40 penetrates the coverlay layer 14 and is connected to the signal wiring 12 (separated wiring part 12-1 and wiring part 12-2).

  The flexible substrate 20 includes a base layer 21 and wirings 22 and 23 provided on one surface 21a and the other surface 21b of the base layer 21, respectively. One of the wiring 22 and the wiring 23 is a signal wiring, and the other is a GND wiring. The signal wiring is provided as a line pattern extending in the direction S, and the GND wiring is provided as a planar pattern including an area corresponding to the area where the signal wiring is provided. The flexible substrate 20 is further provided with an insulating coverlay layer 24 (protective layer) provided on one surface 21 a of the base layer 21 to cover the wiring 22, and provided on the other surface 21 b of the base layer 21 with the wiring 23. And an insulating coverlay layer 25 (protective layer).

  Various insulating materials, for example, resin materials such as polyimide are used for the base layer 21. For the wirings 22 and 23, various conductor materials, for example, metal materials such as Cu are used. For the coverlay layer 24 and the coverlay layer 25, various insulating materials, for example, resin materials such as polyimide are used.

  The adhesive layer 30 is interposed between the flexible substrate 10 and the flexible substrate 20, for example, at both ends 2 in the direction S, and adheres the flexible substrate 10 and the flexible substrate 20. A resin material such as polyimide resin or epoxy resin is used for the adhesive layer 30.

  In the circuit board 1, the flexible board 10 and the flexible board 20 are bonded and laminated by the adhesive layer 30 so that the chip capacitor 40 mounted on the signal wiring 12 of the flexible board 10 is interposed therebetween. The The chip capacitor 40 is provided in a portion (non-adhesive portion) 3 between the flexible substrate 10 and the flexible substrate 20 that is not adhered by the adhesive layer 30. The chip capacitor 40 on the flexible substrate 10 is, for example, in contact with the opposing flexible substrate 20 (its coverlay layer 25) so as to be separable. The chip capacitor 40 may be bonded and fixed to the opposing flexible substrate 20 (the cover lay layer 25) with an adhesive or the like.

  In the circuit board 1, for example, the distance between the flexible board 10 and the flexible board 20 or the thickness of the adhesive layer 30 is based on the height of the chip capacitor 40 used (height from the surface of the coverlay layer 14). Is set. Alternatively, the height of the chip capacitor 40 to be used is set based on the distance between the flexible substrate 10 and the flexible substrate 20 or the thickness of the adhesive layer 30.

  In the circuit board 1 having the above configuration, for example, one end 2 in the direction S in which the signal wiring 12 extends is the input side, and the other end 2 is the output side. The connectors are connected to each other, and signal transmission is performed between the connectors by the signal wiring 12 or the like. By mounting the chip capacitor 40 on the signal wiring 12, a transmission line capable of removing the DC component of the transmission signal and cutting the low frequency band is formed.

  In the circuit board 1, the chip capacitor 40 is interposed in the non-bonding portion 3 between the flexible board 10 and the flexible board 20, thereby allowing the signal wiring 12 of the flexible board 10 and the wiring 23 of the flexible board 20 to approach each other. The resulting deterioration in signal transmission characteristics can be suppressed.

  FIG. 7 is a diagram showing a state when the circuit board according to the first embodiment is bent. FIG. 7 schematically shows a cross-section of the main part when the circuit board according to the first embodiment is bent.

  In the circuit board 1 in which the chip capacitor 40 is provided in the non-bonding portion 3 between the flexible board 10 and the flexible board 20, as shown in FIG. 7, even when bent, between the flexible board 10 and the flexible board 20. Is ensured by the chip capacitor 40. Thereby, the approach between the signal wiring 12 of the flexible substrate 10 and the wiring 23 of the flexible substrate 20 facing the flexible wiring substrate 10 is suppressed, and the deterioration of the signal transmission characteristics of the circuit substrate 1 due to this is suppressed.

  For example, when the wiring 23 of the flexible substrate 20 facing the signal wiring 12 of the flexible substrate 10 is a GND wiring, the proximity of the signal wiring 12 to the opposing GND wiring and the impedance mismatch caused by it can be suppressed. In addition, when the wiring 23 of the flexible substrate 20 that faces the signal wiring 12 of the flexible substrate 10 is a signal wiring, the proximity of the signal wiring 12 to the opposing signal wiring and crosstalk caused thereby can be suppressed.

FIG. 8 is a diagram illustrating an example of signal transmission characteristics of the circuit board.
8A and 8B, when one of the wirings of the flexible substrate facing each other is a signal wiring and the other is a GND wiring, the circuit board is not bent and is bent. The simulation result of impedance is shown. FIG. 8A shows the impedance simulation result when the circuit board is not bent, and FIG. 8B shows the impedance simulation result when the circuit board is bent.

  In FIGS. 8A and 8B, the impedance simulation result of the circuit board (corresponding to the circuit board 300B in FIGS. 2 to 4 above) in which the chip capacitor is not interposed in the non-bonded portion between the flexible boards is shown by the dotted line P. This is shown in the figure. 8A and 8B show the simulation results of the impedance of a circuit board (corresponding to the circuit board 1 shown in FIGS. 6 and 7) in which a chip capacitor is interposed between non-bonded portions between flexible boards. This is indicated by the solid line Q.

  When not bent, as shown in FIG. 8A, a circuit board (dotted line P) in which no chip capacitor is interposed in a non-bonded portion between flexible boards and a circuit board (solid line Q) that is interposed are inserted. Equivalent impedance is shown between the output side connectors (X part, Y part) (FPC).

  When bent, as shown in FIG. 8B, the circuit board (dotted line P) in which the chip capacitor is not interposed between the non-bonded parts between the flexible boards is bent due to the proximity (Z part) between the signal wiring and the GND wiring. The impedance fluctuates as compared to when it is not (FIG. 8A). Further, even in the output side connector (Y portion), the impedance fluctuates as compared with the case where the connector is not bent (FIG. 8A).

  On the other hand, in the circuit board in which the chip capacitor is interposed in the non-bonded portion between the flexible substrates, the proximity of the signal wiring and the GND wiring is suppressed by the chip capacitor even when the circuit board is bent. Therefore, as shown in FIG. 8B, in the circuit board (solid line Q) in which the chip capacitor is interposed between the non-bonded portions between the flexible boards, the impedance variation is suppressed and the circuit board is not bent (FIG. 8A). Impedance equivalent to)) can be obtained.

  As shown in FIG. 8A and FIG. 8B, according to the circuit board in which the chip capacitor is interposed in the non-bonded portion between the flexible boards, the proximity of the signal wiring and the GND wiring, and the impedance fluctuation caused by the proximity. Is effectively suppressed. As a result, impedance mismatch with the subsequent circuit is suppressed, and deterioration of signal transmission characteristics is suppressed. Similarly, when the signal wirings are opposed to each other, their approach and crosstalk caused thereby can be suppressed, and deterioration of signal transmission characteristics can be suppressed.

  As described above, in the circuit board 1, the chip capacitor 40 suppresses the proximity of the signal wiring 12 of the flexible board 10 and the wiring 23 of the flexible board 20 when bent and the deterioration of the signal transmission characteristics due to the proximity. . As described above, by interposing the chip capacitor 40 in the non-bonded portion 3 between the flexible substrate 10 and the flexible substrate 20, the chip capacitor 40 has flexibility and is as high as when it is not bent when bent. A circuit board 1 capable of stably obtaining signal transmission characteristics is realized.

  6 and 7 exemplify a circuit board 1 (four wiring layers) in which two flexible substrates 10 and 20 are bonded with an adhesive layer 30 with a chip capacitor 40 interposed therebetween. However, the number of stacked layers (number of wiring layers) is not limited to this.

FIG. 9 is a diagram showing another example of the circuit board according to the first embodiment. FIG. 9 schematically shows a cross-section of the main part of another example of the circuit board according to the first embodiment.
A circuit board 1A shown in FIG. 9 is a circuit board having three layers (6 wiring layers) including a flexible substrate 10A, a flexible substrate 20A, and a flexible substrate 50.

  The flexible substrate 10A has the same configuration as the flexible substrate 10 described above. The flexible substrate 20A is provided to face the flexible substrate 10A, and is bonded to the flexible substrate 10A with the adhesive layer 30. The flexible substrate 50 is provided to face the flexible substrate 20 </ b> A, and is bonded to the flexible substrate 20 </ b> A with the adhesive layer 60.

  Similar to the adhesive layer 30, the adhesive layer 60 is interposed at both end portions 2 in the direction S between the flexible substrate 20 </ b> A and the flexible substrate 50. A resin material such as a polyimide resin or an epoxy resin is used for the adhesive layer 60. For the adhesive layer 30 and the adhesive layer 60, the same kind of material may be used, or different kinds of materials may be used.

  The flexible substrate 20A is provided with a signal wiring 22a as a wiring 22 on one surface 21a of the base layer 21, and a GND wiring 23a as a wiring 23 on the other surface 21b. The signal wiring 22a and the GND wiring 23a are covered with a coverlay layer 24 and a coverlay layer 25, respectively. An AC coupling chip capacitor 70 is mounted on the signal wiring 22a of the flexible substrate 20A. A group of terminals 70b respectively connected to the group of electrodes 70a of the chip capacitor 70 penetrates the coverlay layer 24 and is connected to the signal wiring 22a (separated wiring part 22a-1 and wiring part 22a-2).

  The flexible substrate 50 includes a base layer 51 and wirings 52 and 53 provided on one surface 51a and the other surface 51b of the base layer 51, respectively. One of the wiring 52 and the wiring 53 is a signal wiring, and the other is a GND wiring. The signal wiring is provided as a line pattern extending in the direction S, and the GND wiring is provided as a planar pattern including an area corresponding to the area where the signal wiring is provided. The wiring 52 and the wiring 53 are covered with an insulating coverlay layer 54 and a coverlay layer 55 (protective layer), respectively.

  Various insulating materials, for example, resin materials such as polyimide are used for the base layer 51. For the wiring 52 and the wiring 53, various conductor materials, for example, metal materials such as Cu are used. For the coverlay layer 54 and the coverlay layer 55, various insulating materials, for example, resin materials such as polyimide are used.

  The chip capacitor 70 mounted on the signal wiring 22 a of the flexible substrate 20 </ b> A is provided in the non-bonding portion 3 between the flexible substrate 20 </ b> A and the flexible substrate 50. For example, the chip capacitor 70 is in contact with the flexible substrate 50 (the cover lay layer 55) facing the flexible substrate 20 so as to be freely separated. The chip capacitor 70 may be fixed to the flexible substrate 50 (the cover lay layer 55) with an adhesive or the like.

  In the circuit board 1 </ b> A, the flexible board 10 </ b> A and the flexible board 20 </ b> A are partially bonded by the adhesive layer 30, and the flexible board 20 </ b> A and the flexible board 50 are partially bonded by the adhesive layer 60. Thereby, the loss of the flexibility of the circuit board 1A due to an increase in the number of stacked layers can be suppressed.

  Further, in the circuit board 1A, the chip capacitor 40 is interposed in the non-bonding portion 3 between the flexible board 10A and the flexible board 20A, and the proximity of the signal wiring 12 of the flexible board 10A and the GND wiring 23a of the flexible board 20A is suppressed. It is done. Further, in the circuit board 1 </ b> A, the chip capacitor 70 is interposed in the non-bonding portion 3 between the flexible board 20 </ b> A and the flexible board 50, and the approach between the signal wiring 22 a of the flexible board 20 </ b> A and the wiring 53 of the flexible board 50 can be suppressed. . By suppressing the proximity between the signal wiring 12 and the GND wiring 23a and the proximity between the signal wiring 22a and the wiring 53, a decrease in the signal transmission characteristics of the circuit board 1A can be suppressed.

As a result, the circuit board 1 </ b> A that has flexibility and can stably obtain high signal transmission characteristics equivalent to that when not bent is realized.
A circuit board having four or more flexible boards (7 or 8 wiring layers) can be realized in the same manner as the circuit board 1A, and the same effect can be obtained.

Subsequently, an example of a method for forming a circuit board will be described.
10 and 11 are diagrams showing an example of a circuit board forming method according to the first embodiment. 10 (A) to 10 (E), FIG. 11 (A), and FIG. 11 (B) each schematically show a cross-section of the main part of the circuit board forming process according to the first embodiment. Yes.

  As shown in FIG. 10A, a substrate 10a having a conductor layer 16 on both surfaces 11a and 11b of the base layer 11 is prepared. A material such as polyimide or liquid crystal polymer is used for the base layer 11. The thickness of the base layer 11 is, for example, 25 μm to 100 μm. A material such as a Cu foil is used for the conductor layer 16. The thickness of the conductor layer 16 is, for example, 10 μm to 35 μm.

  Next, patterning of the conductor layer 16 of the substrate 10a is performed. For the patterning of the conductor layer 16, a photolithography technique and an etching technique are used. By patterning the conductor layer 16, the signal wiring 12 (wiring portions 12-1 and 12-2) sitting in the direction S as shown in FIG. 10B is formed on the one surface 11 a of the base layer 11. The On the other surface 11b of the base layer 11, the conductor layer 16 is not patterned, or the conductor layer 16 is patterned, and the GND wiring 13 is formed. A GND wiring may be formed together with the signal wiring 12 on one surface 11 a of the base layer 11, and a signal wiring may be formed along with the GND wiring 13 on the other surface 11 b of the base layer 11. May be.

  Next, as shown in FIG. 10C, the coverlay layer 14 is formed on the base layer 11 so as to cover the signal wiring 12, and the coverlay layer 15 is formed so as to cover the GND wiring 13. . Materials such as polyimide and solder resist are used for the cover lay layer 14 and the cover lay layer 15. A photosensitive material may be used as the material of the coverlay layer 14 and the coverlay layer 15.

  Next, as shown in FIG. 10D, the coverlay layer 14 that covers the signal wiring 12 is patterned to form an opening 14 a that connects the chip capacitor 40 to the signal wiring 12. The opening 14a of the cover lay layer 14 is formed using a photolithography technique and an etching technique, or using a photolithography technique when a photosensitive material is used for the cover lay layer 14. . If necessary (for example, for electrical connection with a conductive adhesive layer 80 described later), patterning of the coverlay layer 15 covering the GND wiring 13 may be similarly performed.

  Next, as shown in FIG. 10E, the chip capacitor 40 is mounted on the signal wiring 12 in the opening 14 a of the coverlay layer 14. For example, a conductive bonding material such as a solder paste is used, and the electrode 40a group of the chip capacitor 40 is connected to the wiring portions 12-1 and 12-2 of the signal wiring 12 via the terminal 40b group (conductive bonding material), respectively. And electrically connected.

  10A to 10E, the flexible substrate 10A (or the flexible substrate 10) on which the chip capacitor 40 is mounted on the signal wiring 12 is formed.

  The flexible substrate 10A thus formed is bonded to another flexible substrate such as the flexible substrate 20 (FIG. 6) or the flexible substrate 20A (FIG. 9). The flexible substrate 20 can be formed according to the example of FIGS. 10 (A) to 10 (C). The flexible substrate 20A can be formed according to the example of FIGS. 10A to 10E, like the flexible substrate 10A.

  Here, the bonding process will be further described taking the circuit board 1A (FIG. 9) in which the flexible board 10A is bonded to the flexible board 20A and the flexible board 20A is bonded to the flexible board 50 as an example.

  As shown in FIG. 11A, the flexible substrate 10A and the flexible substrate 20A are opposed to each other via the chip capacitor 40 and the adhesive layer 30, and the flexible substrate 20A and the flexible substrate 50 are connected to the chip capacitor 70 and the adhesive layer 60. It is opposed through. For the adhesive layer 30 and the adhesive layer 60, for example, a pre-patterned thermosetting adhesive sheet is used. The adhesive sheet before thermosetting is preferably made slightly thicker than the component height of the chip capacitor 40 and the chip capacitor 70.

  Next, pressure (thermocompression bonding) is applied while heating at a temperature at which the adhesive sheet (adhesive layers 30, 60) is cured. Thus, as shown in FIG. 11B, the flexible substrate 10A and the flexible substrate 20A are bonded by the adhesive layer 30, and the flexible substrate 20A and the flexible substrate 50 are bonded by the adhesive layer 60. It is preferable that the adhesive layer 30 and the adhesive layer 60 obtained by thermal curing of the adhesive sheet are equal to or slightly thinner than the component height of the chip capacitor 40 and the chip capacitor 70, respectively.

The circuit board 1A as shown in FIG. 9 is obtained by the steps as shown in FIGS. 11A and 11B.
Next, a second embodiment will be described.

  FIG. 12 is a diagram illustrating an example of a circuit board according to the second embodiment. FIG. 12A schematically shows a principal plane of an example of the circuit board according to the second embodiment, and FIG. 12B shows the circuit board according to the second embodiment. An example of a cross section of a main part is schematically shown. FIG. 12B is a schematic cross-sectional view taken along line L3-L3 in FIG. In FIG. 12A, for the sake of convenience, the principal part of the upper layer flexible substrate on the mounting surface side of the chip capacitor group is shown by dotted lines.

  The circuit board 1B shown in FIGS. 12A and 12B has a plurality of signal wirings 12 extending in the direction S (four examples here) in the direction T on the base layer 11 in plan view. The flexible substrate 10B is arranged side by side. The signal wiring 12 group of the flexible substrate 10 </ b> B and the GND wiring 13 on the opposite surface side are covered with a cover lay layer 14 and a cover lay layer 15, respectively. A group of AC coupling chip capacitors 40 (chip capacitors 41, 42, 43, 44) are mounted on the signal wiring 12 group of the flexible substrate 10B. A group of electrodes 40 a of each chip capacitor 40 is connected to each signal wiring 12 via a group of terminals 40 b penetrating the coverlay layer 14.

  In accordance with the example described in the first embodiment, such a flexible substrate 10B is provided with another flexible substrate by the adhesive layers 30 provided at both ends 2 in the direction S so that the group of chip capacitors 40 is interposed. It is bonded to 20B (flexible substrates 20, 20A, etc.). The group of chip capacitors 40 is provided in the non-bonding portion 3 between the flexible substrate 10B and the flexible substrate 20B bonded to face the flexible substrate 10B. The group of chip capacitors 40, for example, is in contact with the flexible substrate 20B (its coverlay layer 25) so as to be separable. The group of chip capacitors 40 may be fixed to the flexible substrate 20B (its coverlay layer 25) by bonding with an adhesive or the like.

  For example, as illustrated in FIG. 12, the group of chip capacitors 40 of the flexible substrate 10 </ b> B is mounted on the signal wiring 12 so as to be arranged in a line in a direction T orthogonal to the direction S in plan view.

  Like the circuit board 1 </ b> B, the chip capacitor 40 can be mounted on each signal wiring 12 in the flexible substrate 10 </ b> B having the signal wiring 12 group. Thereby, a transmission line capable of removing a DC component and cutting a low frequency band is realized for each signal wiring 12.

  FIG. 12 shows an example in which the chip capacitor 40 (41 to 44) group is mounted on the signal wiring 12 group so as to be arranged in a line in the direction T. It is not limited to examples.

  FIG. 13 is a diagram illustrating another example of the circuit board according to the second embodiment. FIG. 13A schematically shows a main part plane of another example of the circuit board according to the second embodiment, and FIG. 13B shows a circuit board according to the second embodiment. The cross section of the principal part of another example of is schematically shown. FIG. 13B is a schematic cross-sectional view taken along line L4-L4 of FIG. In FIG. 13A, for the sake of convenience, the main part of the upper flexible substrate on the mounting surface side of the chip capacitor group is shown by dotted lines. In FIG. 13B, for convenience, chip capacitors other than the chip capacitor at the L4-L4 cross-sectional position are illustrated by dotted lines.

  The flexible substrate 10C of the circuit board 1C shown in FIGS. 13A and 13B is configured so that the chip capacitor 40 (41 to 44) group is directed to the signal wiring 12 group extending in the direction S. It is mounted with the position shifted to S. The flexible board 10C of the circuit board 1C is different from the flexible board 10B of the circuit board 1B in this respect. Such a flexible substrate 10C is bonded to another flexible substrate 20C (flexible substrates 20, 20A, etc.) by the adhesive layers 30 provided at both ends 2 in the direction S so that the group of chip capacitors 40 is interposed. .

  As shown in FIGS. 13A and 13B, the group of chip capacitors 40 (41 to 44) may be arranged with their positions shifted in the direction S from each other. The chip capacitors 40 arranged in this way also realize a transmission line capable of removing a DC component and cutting a low frequency band for each signal wiring 12.

  Further, according to the arrangement of the chip capacitor 40 group as shown in FIGS. 13A and 13B, an increase in the pitch and the number of the signal wirings 12 group and an increase in the width of the circuit board 1C can be suppressed. .

  For example, as in the case of the circuit board 1B shown in FIG. 12, when the chip capacitors 40 are mounted on the signal wirings 12 so as to be arranged in a line in the direction T, they are adjacent to each other depending on the width of the chip capacitors 40 to be used. It is possible that the chip capacitors 40 interfere with each other. In this case, in order to avoid interference between adjacent chip capacitors 40, the number of the signal wirings 12 group on the circuit board 1B can be reduced or the number of the signal wirings 12 group can be maintained by increasing the pitch of the signal wirings 12 group. It may be necessary to increase the width of the circuit board 1B. That is, there is a possibility that the number of transmission lines on the circuit board 1B is reduced and the circuit board 1B is enlarged.

  On the other hand, according to the arrangement of the chip capacitors 40 as shown in FIGS. 13A and 13B, even when the chip capacitors 40 having such a size as to interfere when arranged in a line in the direction T are used. By shifting their mounting positions in the direction S, interference can be avoided. Therefore, it is not necessary to increase the pitch of the signal wirings 12 group for mounting the chip capacitors 40 group, and the number of signal wirings 12 groups that can be generated by increasing the pitch and the width of the circuit board 1C are increased. It can be suppressed.

  FIG. 14 is a diagram showing still another example of the circuit board according to the second embodiment. FIG. 14 schematically shows a cross-section of the main part of another example of the circuit board according to the second embodiment. In FIG. 14, for convenience, chip capacitors other than the chip capacitor at the cross-sectional position are shown by dotted lines.

A circuit board 1D illustrated in FIG. 14 includes a flexible board 10D, a flexible board 20D, and a flexible board 50.
The flexible substrate 10D has a configuration similar to that of the flexible substrate 10C, and includes a group of signal wires 12 extending in the direction S and a chip capacitor 40 (41 to 44) mounted on each of the signal capacitors 12 while being displaced in the direction S. ) Group.

  The flexible substrate 20D includes a group of signal wirings 22a extending in the direction S on the base layer 21 (only one of the cross-sectional positions is shown in FIG. 14), and a chip mounted on each of the signal lines 22a while being shifted in the direction S. And a group of capacitors 70 (chip capacitors 71, 72, 73, 74). The signal wiring 22a group (wiring 22) and the GND wiring 23a (wiring 23) on the opposite surface side are covered with a cover lay layer 24 and a cover lay layer 25, respectively. A group of electrodes 70 a of each chip capacitor 70 is connected to each signal wiring 22 a via a group of terminals 70 b that penetrate the coverlay layer 24.

  The flexible substrate 10D is bonded to the flexible substrate 20D with an adhesive layer 30 provided at both ends 2 in the direction S so that the group of chip capacitors 40 (41 to 44) is interposed. The flexible substrate 20D is bonded to the flexible substrate 50 with an adhesive layer 60 provided at both ends 2 in the direction S so that the group of chip capacitors 70 (71 to 74) is interposed.

  The group of chip capacitors 40 is, for example, in contact with the flexible substrate 20D (its coverlay layer 25) so as to be separable. The group of chip capacitors 40 may be fixed by being bonded to the flexible substrate 20D (its coverlay layer 25) with an adhesive or the like. Further, the group of chip capacitors 70 is, for example, in contact with the flexible substrate 50 (the cover lay layer 55) so as to be separable. The group of chip capacitors 70 may be fixed to the flexible substrate 50 (the cover lay layer 55) by bonding with an adhesive or the like.

  In the circuit board 1D shown in FIG. 14, the mounting positions of the group of chip capacitors 40 interposed between the flexible board 10D and the flexible board 20D are shifted in the direction S with respect to each other. Further, the mounting positions of the chip capacitors 70 interposed between the flexible substrate 20D and the flexible substrate 50 are shifted in the direction S with respect to each other. In this case, the mounting position of the chip capacitors 70 between the flexible substrate 20D and the flexible substrate 50 is as shown in FIG. 14 with respect to the mounting position of the chip capacitors 40 between the flexible substrate 10D and the flexible substrate 20D. And may be shifted in the direction S.

In this way, a circuit board 1D having three stacked sheets can be realized. A circuit board having four or more stacked layers can also be realized in the same manner as the circuit board 1D.
Next, a third embodiment will be described.

FIG. 15 is a diagram illustrating an example of a circuit board according to the third embodiment. FIG. 15 schematically shows a principal plane of an example of a circuit board according to the third embodiment.
A circuit board 1E shown in FIG. 15 includes a flexible board 10E on which the chip capacitor 40 is mounted on the signal wiring 12, and a flexible board 20E on which the chip capacitor 70 is mounted on the signal wiring 22a (wiring 22). The signal wiring 12 of the flexible substrate 10E is provided on the surface 11a of the base layer 11, and the signal wiring 12 and the GND wiring 13 on the opposite surface 11b are covered with the coverlay layer 14 and the coverlay layer 15, respectively. The signal wiring 22a of the flexible substrate 20E is provided on the surface 21a of the base layer 21, and the signal wiring 22a and the GND wiring 23a on the opposite surface 21b are covered with the coverlay layer 24 and the coverlay layer 25, respectively.

  In the circuit board 1E, the mounting surface side of the chip capacitor 40 of the flexible substrate 10E faces the mounting surface side of the chip capacitor 70 of the flexible substrate 20E. The flexible substrate 10E and the flexible substrate 20E are bonded to each other with an adhesive layer 30 provided at both ends 2 in the direction S so that the chip capacitor 40 and the chip capacitor 70 are interposed.

  The chip capacitor 40 is, for example, in contact with the flexible substrate 20E (its coverlay layer 24) so as to be separable. The chip capacitor 40 may be fixed to the flexible substrate 20E (its coverlay layer 24) by bonding with an adhesive or the like. Further, the chip capacitor 70 is in contact with the flexible substrate 10E (its coverlay layer 14), for example, so as to be separable. The chip capacitor 70 may be fixed by being adhered to the flexible substrate 10E (its coverlay layer 14) with an adhesive or the like.

  In the circuit board 1E, since the flexible board 10E and the flexible board 20E are partially bonded and laminated by the adhesive layer 30, the loss of flexibility of the circuit board 1E due to the lamination can be suppressed.

  In the circuit board 1E, the chip capacitor 40 and the chip capacitor 70 realize a transmission line capable of removing a DC component and cutting a low frequency band for the signal wiring 12 of the flexible board 10E and the signal wiring 22a of the flexible board 20E. Is done. In the circuit board 1E, the chip capacitor 40 and the chip capacitor 70 suppress crosstalk due to the proximity of the signal wiring 12 of the flexible board 10E and the signal wiring 22a of the flexible board 20E when bent, and the signal transmission characteristics resulting therefrom. Can be prevented from decreasing.

A circuit board 1E that is flexible and can stably obtain high signal transmission characteristics equivalent to that when it is not bent is realized.
According to the example of the circuit board 1E, flexible substrates each having a chip capacitor group mounted on the signal wiring group can be bonded and laminated.

  For example, as described in FIG. 12 above, the flexible substrates in which the chip capacitor groups are arranged in a row in a direction orthogonal to the extending direction of the signal wiring groups are arranged so that the mounting surfaces of these chip capacitor groups face each other. Glue the ends. In this case, the mounting positions (rows) of the chip capacitor groups on both flexible boards are shifted in the extending direction of the signal wiring group.

  Further, as described in FIG. 13 and FIG. 14 above, the flexible substrates in which the chip capacitor groups are arranged while being shifted in the extending direction of the signal wiring groups are arranged so that the mounting surface sides of these chip capacitor groups face each other. Glue the ends. In this case, the mounting position of the chip capacitor group on the other flexible substrate is shifted in the extending direction of the signal wiring group with respect to the mounting position of the chip capacitor group on one flexible substrate.

Next, a fourth embodiment will be described.
FIG. 16 is a diagram illustrating an example of a circuit board according to the fourth embodiment. FIG. 16A schematically illustrates a side surface of an example of the circuit board according to the fourth embodiment, and FIG. 16B illustrates the circuit board according to the fourth embodiment. An example of a cross section of a main part is schematically shown. FIG. 16B is a schematic cross-sectional view taken along line L5-L5 in FIG.

  In the circuit board 1F shown in FIGS. 16A and 16B, the flexible substrate 10F and the flexible substrate 20F are bonded to each other with the adhesive layer 30 at both ends 2 in the direction S and bonded to both ends 4 in the direction T. The structure is bonded with the layer 80. Here, in addition to the flexible substrates 10C and 10D, the flexible substrates 10F, 10A, 10B, and 10E may be used as the flexible substrate 10F. As the flexible substrate 20F, the flexible substrates 20, 20A, 20B, 20C, 20D, and 20E may be used.

  In the circuit board 1F shown in FIG. 16A and FIG. 16B, an insulating material is used for the adhesive layers 30 at both ends 2 in the direction S, and the adhesive layers 80 at both ends 4 in the direction T A conductive material is used. As the conductive material of the adhesive layer 80, a conductive film, a conductive paste (for example, silver (Ag) paste), or the like that includes an insulating resin containing a conductive filler can be used.

  The adhesive layer 80 using the conductive material is provided as a continuous wall continuously extending in the direction S along each end portion 4 as shown in FIGS. . The adhesive layer 80 is electrically connected to a conductor portion having a GND potential, which is provided on at least one of the flexible substrate 20F and the flexible substrate 10F.

  In the circuit board 1F, the conductive adhesive layer 80 that is provided as a continuous wall in the direction S, that is, the extending direction of the signal wiring 12, and is GND-connected exhibits an electromagnetic shielding function. Such an adhesive layer 80 suppresses the incidence of electromagnetic waves to the circuit board 1F and the radiation of electromagnetic waves from the circuit board 1F, deterioration of signal transmission characteristics of the circuit board 1F, and other arrangements around the circuit board 1F. Deterioration of characteristics of electronic parts can be suppressed.

  FIG. 17 is a diagram illustrating an example of a method of forming a circuit board according to the fourth embodiment. FIG. 17A and FIG. 17B schematically show the main part side surface of the circuit board forming step according to the fourth embodiment.

  The flexible substrate 10F and the flexible substrate 20F prepared according to the example of the method as described in FIG. 10A to FIG. 10E are connected to the chip capacitor 40 and the adhesive layer as shown in FIG. 30 and the adhesive layer 80. Here, an insulating adhesive sheet having a predetermined shape can be used for the adhesive layer 30. A conductive film having a predetermined shape can be used for the adhesive layer 80. The flexible substrate 10F and the flexible substrate 20F are thermocompression bonded via the chip capacitor 40 and, for example, such an adhesive layer 30 and the adhesive layer 80, thereby curing the adhesive layer 30 and the adhesive layer 80, and FIG. A circuit board 1F as shown in B) is obtained.

  When a conductive paste is used for the adhesive layer 80, the conductive paste is disposed along the end portion 4 by a dropping method using a dispenser or the like, and the flexible substrate 10F and the flexible substrate 20F are thermocompression bonded. As a result, the adhesive layer 30 and the adhesive layer 80 are cured to obtain a circuit board 1F as shown in FIG.

  In order to connect the adhesive layer 80 to the GND, at least one of the cover lay layer 14 and the cover lay layer 25 is patterned in advance according to the example of the process of FIG. Exposed. The conductor layer exposed from the cover lay layer 14 or the cover lay layer 25 is formed by, for example, drilling (drilling or etching) and plating the circuit board 1F after being bonded by the adhesive layer 30 and the adhesive layer 80 as described above, and plating. You may electrically connect with the conductor layer of the opposite surface side. Such a technique is used to realize the GND connection of the adhesive layer 80 on the circuit board 1F.

The electromagnetic shield by the adhesive layer 80 can also be realized by a circuit board 1G as shown in FIG.
FIG. 18 is a diagram illustrating another example of the circuit board according to the fourth embodiment. FIG. 18A schematically shows a side surface of a main part of another example of the circuit board according to the fourth embodiment, and FIG. 18B shows a circuit board according to the fourth embodiment. The cross section of the principal part of another example of is schematically shown. FIG. 18B is a schematic cross-sectional view taken along the line L6-L6 of FIG.

  The circuit board 1G shown in FIG. 18A and FIG. 18B is provided with the adhesive layer 80 that adheres both ends 4 of the flexible substrate 10F and the flexible substrate 20F as post walls dotted in the direction T. This is different from the circuit board 1F. The adhesive layer 80 is electrically connected to a conductor portion having a GND potential, which is provided on at least one of the flexible substrate 20F and the flexible substrate 10F. A conductive adhesive layer 80 provided as a post wall in the direction S, that is, in the extending direction of the signal wiring 12 and connected to the GND, also exhibits an electromagnetic shielding function, and deteriorates signal transmission characteristics of the circuit board 1G. The characteristic deterioration of other electronic components arranged around 1F is suppressed.

  FIG. 19 is a diagram showing another example of a method for forming a circuit board according to the fourth embodiment. FIG. 19A and FIG. 19B each schematically show the side surface of the main part of the circuit board forming step according to the fourth embodiment.

  The flexible substrate 10F and the flexible substrate 20F prepared according to the example of the method as described in FIG. 10A to FIG. 10E are replaced with a chip capacitor 40, an adhesive layer as shown in FIG. 30 and the adhesive layer 80. For the adhesive layer 30, an insulating adhesive sheet having a predetermined shape is used. In the formation of the circuit board 1G, a conductive paste is disposed as the adhesive layer 80 at a predetermined position as shown in FIG. 19A, for example, by a dropping method using a dispenser or the like. Then, the adhesive layer 30 and the adhesive layer 80 are cured by thermocompression bonding of the flexible substrate 10F and the flexible substrate 20F to obtain a circuit substrate 1G as shown in FIG.

  In order to connect the adhesive layer 80 to the GND, at least one of the cover lay layer 14 and the cover lay layer 25 is patterned in advance according to the example of the process of FIG. Exposed. The conductor layer exposed from the cover lay layer 14 or the cover lay layer 25 is formed by, for example, drilling (drilling or etching) and plating the circuit board 1G after being bonded by the adhesive layer 30 and the adhesive layer 80 as described above. You may electrically connect with the conductor layer of the opposite surface side. Such a technique is used to realize the GND connection of the adhesive layer 80 in the circuit board 1G.

  As described in the fourth embodiment, the continuous wall or post wall adhesive layer 80 provided at the end 4 in the direction T perpendicular to the direction S is the same as that in the first to third embodiments. The circuit board 1, 1A, 1B, 1C, 1D, 1E described above can be similarly applied.

Next, a fifth embodiment will be described.
The circuit boards 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G and the like as described in the first to fourth embodiments can be used for signal transmission between electronic components.

FIG. 20 is a diagram illustrating an example of an electronic apparatus according to the fifth embodiment. FIG. 20 schematically illustrates a cross-section of an essential part of an example of an electronic apparatus according to the fifth embodiment.
An electronic device 100 shown in FIG. 20 includes an electronic component 110 and an electronic component 120, and a circuit board that electrically connects them, for example, the circuit board 1 described in the first embodiment.

  The electronic component 110 includes a mother board 111 (circuit board), a semiconductor chip 112 (semiconductor element) such as an IC (Integrated Circuit) mounted on the mother board 111, and a connector 113. The mother board 111 includes a signal line 111a (SIG) and a GND line 111b (GND). The signal line 111 a is connected to a signal terminal 112 a such as a solder bump or Cu pillar of the semiconductor chip 112 and a signal terminal 113 a of the connector 113. The GND line 111b is connected to the GND terminal 112b of the semiconductor chip 112 and the GND terminal 113b of the connector 113.

  Similarly, the electronic component 120 includes a motherboard 121 (circuit board), a semiconductor chip 122 (semiconductor element) such as an IC mounted on the motherboard 121, and a connector 123. The motherboard 121 includes a signal line 121a (SIG) and a GND line 121b (GND). The signal line 121 a is connected to a signal terminal 122 a such as a solder bump or Cu pillar of the semiconductor chip 122 and a signal terminal 123 a of the connector 113. The GND line 121 b is connected to the GND terminal 122 b of the semiconductor chip 122 and the GND terminal 123 b of the connector 123.

The circuit board 1 (multilayer flexible circuit board) has one end connected to the connector 113 of the electronic component 110 and the other end connected to the connector 123 of the electronic component 120.
When the circuit board 1 is connected to the connector 113, the signal wiring 12 of the flexible board 10 included in the circuit board 1 and the wiring 22 or wiring 23 that is the signal wiring of the flexible board 20 are connected to the signal terminal 113 a of the connector 113. Connected to. Further, the GND wiring 13 of the flexible substrate 10 and the wiring 23 or the wiring 22 which is the GND wiring of the flexible substrate 20 are connected to the GND terminal 113 b of the connector 113.

  Similarly, when the circuit board 1 is connected to the connector 123, the signal wiring 12 of the flexible board 10 included in the circuit board 1 and the wiring 22 or wiring 23 that is the signal wiring of the flexible board 20 are connected to the signal terminal 123a. Connected to. Further, the GND wiring 13 of the flexible substrate 10 and the wiring 23 or the wiring 22 which is the GND wiring of the flexible substrate 20 are connected to the GND terminal 123 b of the connector 123.

  In the electronic device 100, signal transmission is performed between the electronic component 110 and the electronic component 120 via the circuit board 1. For example, a signal output from the semiconductor chip 112 on the electronic component 110 side is input to the signal wiring 12 of the circuit board 1 through the signal terminal 112a, the signal line 111a of the motherboard 111, and the signal terminal 113a of the connector 113. The A signal input to the circuit board 1 is transmitted to the electronic component 120 side through the signal wiring 12 and the like, and is transmitted to the semiconductor chip 122 via the signal terminal 123a of the connector 123, the signal line 121a of the motherboard 121, and the signal terminal 122a. Entered.

  As described above, in the circuit board 1, by mounting the chip capacitor 40 on the signal wiring 12, it is possible to remove the DC component of the transmitted signal and cut the low frequency band. Further, in the circuit board 1, the chip capacitor 40 mounted on the signal wiring 12 suppresses the approach between the signal wiring 12 and the wiring 23 even when bent, and the signal transmission characteristics equivalent to those when not bent are obtained. can get. By using such a circuit board 1, a highly reliable and high quality electronic device 100 that exhibits stable performance is realized.

  Here, the circuit board 1 described in the first embodiment is taken as an example, but other circuit boards 1A, 1B, 1C, 1D, 1E, 1F, 1G, etc. are used, and the electronic component 110 and the electronic component 120 are used. It is possible to perform signal transmission between them. The configurations of the electronic component 110 and the electronic component 120 described above are merely examples, and the signal transmission between various electronic components can be performed using the circuit board 1 or the like.

Next, a sixth embodiment will be described.
Electronic devices using the circuit boards 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G and the like as described in the first to fourth embodiments are used in various electronic devices (also referred to as electronic devices). Can be installed. For example, it can be used for various electronic devices such as computers (personal computers, supercomputers, servers, etc.), smart phones, mobile phones, tablet terminals, sensors, cameras, audio devices, measuring devices, inspection devices, and manufacturing devices.

FIG. 21 is a diagram illustrating an example of an electronic apparatus according to the sixth embodiment. FIG. 21 schematically illustrates an example of an electronic device.
As shown in FIG. 21, for example, the electronic device 100 as shown in FIG. 20 is mounted (built in) the various electronic devices 200. As described above, in the circuit board 1 used in the electronic device 100, the chip capacitor 40 can remove the DC component of the signal transmitted between the electronic component 110 and the electronic component 120 and cut the low frequency band. Become. Further, even when bent, the approach between the wires is suppressed, and stable signal transmission characteristics can be obtained. As a result, a highly reliable and high quality electronic device 100 capable of stably exhibiting performance is realized, and a highly reliable and high quality electronic device 200 equipped with such an electronic device 100 is realized.

  Here, the electronic device 100 using the circuit board 1 as described in the fifth embodiment is taken as an example, but the circuit boards 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G and the like are used. Similarly, the various electronic devices used can be mounted on various electronic devices.

  In the above description, the chip capacitor is interposed between the flexible substrates included in the multilayer flexible circuit board. However, instead of the chip capacitor or together with the chip capacitor, other electronic components such as a chip resistor and a chip inductor are interposed. It may be. By using such an electronic component, it is possible to suppress the approach between the flexible substrates (between those wirings) when the multilayer flexible circuit substrate is bent, and to suppress the deterioration of the signal transmission characteristics due to the proximity.

Regarding the embodiment described above, the following additional notes are further disclosed.
(Additional remark 1) The 1st flexible substrate which has a 1st insulating layer and the 1st signal wiring provided in the 1st surface of the 1st insulating layer, and extended in the 1st direction,
A second flexible substrate facing the first surface;
An adhesive layer interposed in a first region between the first flexible substrate and the second flexible substrate;
And a first electronic component mounted on the first signal wiring and interposed in a second region different from the first region between the first flexible substrate and the second flexible substrate. Circuit board to do.

(Supplementary note 2) The circuit board according to supplementary note 1, wherein the first electronic component is in contact with the second flexible substrate on a side opposite to the first signal wiring side.
(Supplementary Note 3) The first flexible substrate further includes a second signal wiring provided on the first surface and extending in the first direction,
The circuit board according to appendix 1 or 2, further comprising a second electronic component interposed in the second region and mounted on the second signal wiring.

(Supplementary Note 4) The first flexible substrate further includes a second signal wiring provided on the first surface and extending in the first direction,
Supplementary note 1 further comprising a second electronic component interposed in the second region and mounted on the second signal wiring at a position shifted in the first direction with respect to the first electronic component. Or the circuit board of 2.

(Supplementary Note 5) The circuit board according to Supplementary Note 3 or 4, wherein the second electronic component is in contact with the second flexible substrate on a side opposite to the second signal wiring side.
(Appendix 6) The second flexible substrate is:
A second insulating layer;
The circuit board according to any one of appendices 1 to 5, further comprising: a first ground wiring provided on a second surface of the second insulating layer facing the first surface.

(Appendix 7) The second flexible substrate is
A second insulating layer;
And a third signal wiring provided on a second surface of the second insulating layer facing the first surface and extending in the first direction. Circuit board.

(Supplementary note 8) The circuit board according to supplementary note 7, wherein the second flexible substrate further includes a third electronic component interposed on the second region and mounted on the third signal wiring.
(Supplementary note 9) The circuit board according to supplementary note 8, wherein the third electronic component is in contact with the first flexible substrate on a side opposite to the third signal wiring side.

  (Additional remark 10) The said contact bonding layer contains the electroconductive adhesion part provided in the edge part of the 2nd direction orthogonal to the said 1st direction of the said 1st flexible substrate and the said 2nd flexible substrate, It is characterized by the above-mentioned. The circuit board according to any one of appendices 1 to 9.

  (Additional remark 11) The said adhesion part is electrically connected with the 2nd ground wiring provided in the said 1st flexible substrate or the said 2nd flexible substrate, The circuit board of Additional remark 10 characterized by the above-mentioned.

(Additional remark 12) The said adhesion part is a continuous wall extended in the said 1st direction, The circuit board of Additional remark 10 or 11 characterized by the above-mentioned.
(Additional remark 13) The said adhesion part is the post wall dotted in the said 1st direction, The circuit board of Additional remark 10 or 11 characterized by the above-mentioned.

(Supplementary Note 14) The first region of the first region of the first flexible substrate having the first insulating layer and the first signal wiring provided on the first surface of the first insulating layer and extending in the first direction. Mounting the first electronic component on the signal wiring;
The first flexible substrate on which the first electronic component is mounted, and the second flexible substrate disposed to face the first surface, and the first flexible substrate between the first flexible substrate and the second flexible substrate. And a step of adhering with an adhesive layer in a second region different from the first region.

(Supplementary Note 15) A first flexible substrate having a first insulating layer and a first signal wiring provided on the first surface of the first insulating layer and extending in the first direction;
A second flexible substrate facing the first surface;
An adhesive layer interposed in a first region between the first flexible substrate and the second flexible substrate;
A first circuit board including a first electronic component mounted on the first signal wiring and interposed in a second area different from the first area between the first flexible board and the second flexible board. When,
An electronic device comprising: a second electronic component provided at an end portion of the first circuit board in the first direction and electrically connected to the first signal wiring.

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 300A, 300B Circuit board 2, 4 End portion 3, 340 Non-adhered portion 10, 10A, 10B, 10C, 10D, 10E, 10F, 20, 20A, 20B, 20C, 20D, 20E, 20F, 50, 310, 320 Flexible board 10a Board 11, 21, 51, 311, 321 Base layer 11a, 11b, 21a, 21b, 51a, 51b, 311a, 311b, 321a, 321b 12, 22a, 312a, 312b, 322a, 323b Signal wiring 12-1, 12-2, 22a-1, 22a-2 Wiring part 13, 23a, 313a, 313b, 322b, 323a GND wiring 14, 15, 24, 25 , 54, 55, 314, 315, 324, 325 Coverlay layer 14a opening 16 conductor Layer 22, 23, 52, 53, 312, 313, 322, 323 Wiring 30, 60, 80, 330 Adhesive layer 40, 41, 42, 43, 44, 70, 71, 72, 73, 74 Chip capacitors 40a, 70a Electrode 40b, 70b Terminal 100 Electronic device 110, 120 Electronic component 111, 121 Mother board 111a, 121a Signal line 111b, 121b GND line 112, 122 Semiconductor chip 112a, 113a, 122a, 123a Signal terminal 112b, 113b, 122b, 123b GND terminal 113,123 connector 200 electronic device (electronic device)

Claims (8)

A first flexible substrate having a first insulating layer and a first signal wiring provided on a first surface of the first insulating layer and extending in a first direction;
A second flexible substrate facing the first surface;
An adhesive layer interposed in a first region between the first flexible substrate and the second flexible substrate;
And a first electronic component mounted on the first signal wiring and interposed in a second region different from the first region between the first flexible substrate and the second flexible substrate. Circuit board to do. The first flexible substrate further includes a second signal wiring provided on the first surface and extending in the first direction,
2. The electronic device according to claim 1, further comprising a second electronic component interposed in the second region and mounted on the second signal wiring at a position shifted in the first direction with respect to the first electronic component. The circuit board according to 1. The second flexible substrate is
A second insulating layer;
The circuit board according to claim 1, further comprising: a first ground wiring provided on a second surface of the second insulating layer facing the first surface. The second flexible substrate is
A second insulating layer;
3. The circuit according to claim 1, further comprising: a third signal wiring provided on a second surface of the second insulating layer opposite to the first surface and extending in the first direction. substrate.   5. The circuit board according to claim 4, wherein the second flexible board further includes a third electronic component interposed in the second region and mounted on the third signal wiring. 6.   The adhesive layer includes a conductive adhesive portion provided at an end portion of the first flexible substrate and the second flexible substrate in a second direction orthogonal to the first direction. The circuit board according to any one of 5 to 5. A first flexible substrate having a first insulating layer and a first signal wiring provided on a first surface of the first insulating layer and extending in a first direction on the first signal wiring in a first region. Mounting the first electronic component;
The first flexible substrate on which the first electronic component is mounted, and the second flexible substrate disposed to face the first surface, and the first flexible substrate between the first flexible substrate and the second flexible substrate. And a step of adhering with an adhesive layer in a second region different from the first region. A first flexible substrate having a first insulating layer and a first signal wiring provided on a first surface of the first insulating layer and extending in a first direction;
A second flexible substrate facing the first surface;
An adhesive layer interposed in a first region between the first flexible substrate and the second flexible substrate;
A first circuit board including a first electronic component mounted on the first signal wiring and interposed in a second area different from the first area between the first flexible board and the second flexible board. When,
An electronic device comprising: a second electronic component provided at an end portion of the first circuit board in the first direction and electrically connected to the first signal wiring.

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