JP2012015178A - Flex rigid wiring substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flex rigid wiring substrate and a method for manufacturing the same with which a substrate having high adhesiveness among respective layers can be manufactured in a simple process and the thickness of a rigid portion can be made more uniform.SOLUTION: A flex rigid wiring substrate comprises a step of heating and pressing a laminate member in which a flexible wiring substrate 10 is sandwiched through prepregs 11 from both the sides thereof by rigid wiring substrate laminate units to integrate the laminate member, and a step of forming an interlayer connection portion for conductively connecting a wiring pattern formed at an end portion 10a of the flexible wiring plate 10 to a wiring pattern of the rigid wiring substrate. In the laminate member, the prepregs 11 at both the sides for adhesively attaching the laminate units at both the sides sandwich the end portion 10a of the flexible wiring substrate 10, and other prepregs 31 sandwich the residual portion.

Description

  The present invention relates to a flex-rigid wiring board having a flex part and a rigid part on a single wiring board, and a manufacturing method thereof.

  Conventionally, hard rigid wiring boards and soft flexible wiring boards were generally used as wiring boards, but flex rigid wiring boards having a flex part and a rigid part have also been developed in order to have the advantages of both. Progressing. As shown in FIG. 6 (c), this flex-rigid wiring board can be mounted with components, has a rigid portion 18 that can withstand the weight of the components, and has strength to be fixed to the casing, and can be freely bent to form a small space. And a flex portion 17 connecting between the wiring board and the connector or between the wiring boards.

  Such a flex-rigid wiring board has been conventionally formed by the method shown in FIG. First, as shown to Fig.6 (a), the semi-hardened prepreg 11 which served as both insulation and adhesion | attachment is mounted on the both surfaces (or one side) of the flexible wiring board 10 to which the printed wiring was given previously. At this time, a gap portion 15 is formed in a portion that becomes the flex portion 17. On the prepreg 11, a copper foil 12 that forms a printed wiring of the rigid portion 18 is further placed. Furthermore, it heats, covering with the thick release film 13 and pressing with the up-and-down mirror plate 14.

  As shown in FIG. 6B, the prepreg 11 is formed in a semi-cured state (B-stage) by applying a mixture of a thermosetting resin and a curing agent to a reinforcing material made of glass fiber. Yes, when heated while pressing, the resin and the curing agent react inside the prepreg 11 to be temporarily softened and then cured to act as an adhesive for connecting the flexible wiring board 10 and the copper foil 12. And an insulating layer.

  As shown in FIG. 6C, after the prepreg 11 is cured, a flex-rigid wiring board in which the exudation portion 16 is formed in a state where the resin flows out to the flex portion 17 when the mirror plate 14 and the release film 13 are removed. It becomes. Moreover, in order to suppress the flow of the prepreg 11, conventionally, a low-flow prepreg having a low flow has been used.

  However, in the conventional manufacturing method of the flex-rigid wiring board, since the flexible wiring board is disposed on the entire surface of the wiring board, the amount of expensive flexible wiring board used is large and the cost is high. Since the material is usually different from other materials of the rigid part, it is difficult to control the impedance of the substrate, and the problem of deformation and peeling due to the difference in thermal expansion coefficient is likely to occur, and the reliability of the wiring substrate is lowered.

  For the purpose of solving this problem, only the end of the flexible wiring board constituting the flex part of the flex-rigid wiring board is sandwiched between the insulating layers of the rigid part, and the wiring pattern formed at the end is rigid. There has also been proposed a structure in which the wiring pattern of the part is conductively connected at the interlayer connection part (see, for example, Patent Document 1). In this flex-rigid wiring board manufacturing method, when a laminate in which a flexible wiring board is sandwiched from both sides via a prepreg is integrated by heating and pressurizing, the laminate is attached to the end of the flexible wiring board. The method of arrange | positioning so that only a part may be inserted | pinched is employ | adopted.

  However, in this manufacturing method, since only the end portion of the flexible wiring board is sandwiched between the prepregs forming the rigid portion, the portion where the end portion is sandwiched is likely to be thicker than the other portions, and the thickness of the rigid portion is constant. There was a problem that it was difficult to make.

  In addition, in Patent Document 2, when manufacturing a flex-rigid wiring board in which an end portion of a flexible wiring board is sandwiched between insulating layers of a rigid portion, an inflexible base material is adjacent to the end portion of the flexible wiring board. In this state, an insulating layer is formed on both sides of the wiring layer, and a wiring layer and an insulating layer are sequentially formed while performing via connection.

  However, in this manufacturing method, handling of the flexible wiring board sandwiched between the insulating layers becomes a problem, so it becomes difficult to form the rigid portion by the normal manufacturing method of the rigid wiring board, and once the entire is formed in a rigid state. After that, there is a problem that the manufacturing process becomes complicated, such as adopting a process of removing a portion laminated on the flexible wiring board. In addition, since a non-flexible base material (cured product) such as glass epoxy resin is used, it becomes difficult for the resin to be filled in the gap between the ends of the adjacent flexible wiring boards, and the strength and adhesion are reduced. There was a problem.

JP 2006-294666 A International Patent Publication WO2008-050399

  Accordingly, an object of the present invention is to provide a flex-rigid wiring board capable of manufacturing a substrate with high adhesion of each layer by a simple process and making the thickness of the rigid portion more uniform, and a method for manufacturing the same. is there.

The above object can be achieved by the present invention as described below.
That is, the method for manufacturing a flex-rigid wiring board according to the present invention includes a step of heating and pressing a laminate in which a flexible wiring board is sandwiched from both sides via a prepreg in a unit of lamination of the rigid wiring board; A method of manufacturing a flex-rigid wiring board, including a step of forming an interlayer connection portion for conductively connecting the wiring pattern formed at the end of the wiring pattern and the wiring pattern of the rigid wiring board, wherein the laminate includes the both sides The prepregs on both sides for adhering the laminated unit are sandwiched between the end portions of the flexible wiring board and another prepreg is sandwiched between the remaining portions.

  According to the manufacturing method of the present invention, the prepregs on both sides for adhering the laminated units on both sides sandwich the end of the flexible wiring board, and the remaining part has a structure in which another prepreg is sandwiched. Compared with the case where only the end portion is sandwiched, the presence of another prepreg makes it easy to make the thickness of the rigid portion uniform. At that time, since a prepreg is used instead of a cured product, the resin is easily filled in the gap between the end of the flexible wiring board and the like, and the strength and adhesion can be improved. In addition, the flex part and the rigid part can be formed by a process of heating and pressurizing and integrating the laminate in which the flexible wiring board is sandwiched from both sides in a laminate unit of the rigid wiring board through the prepreg, so that the flex rigid A wiring board can be manufactured. As a result, it is possible to provide a method for manufacturing a flex-rigid wiring board in which a substrate with high adhesion between layers can be manufactured by a simple process and the thickness of the rigid portion can be made more uniform.

  In the above, it is preferable that the another prepreg has a cutout portion or a cutout portion for disposing an end portion of the flexible wiring board. Thereby, the level | step difference around the edge part of a flexible wiring board can be made small, and thickness can be equalized in the whole surface of a rigid part. In particular, when the other prepreg has a cut-out portion, and a flexible wiring board is arranged in the cut-out portion, the resin is more in comparison with the case where the end side of the other prepreg is arranged along the end side of the rigid portion. Since the influence of the flow is reduced, the thickness can be made more uniform over the entire surface of the rigid portion.

  Moreover, it is preferable that said another prepreg is a thing with the fluidity | liquidity in the temperature at the time of heating-pressing is higher than the prepreg of the both sides. Thus, by using a prepreg having high fluidity, the filling and entering of the resin are improved, whereby the adhesion of each layer can be further improved.

  Furthermore, it is preferable that the other prepreg has substantially the same thickness as the flexible wiring board or a slightly thinner thickness. Thereby, the thickness of a rigid part can be made uniform more reliably.

  On the other hand, the flex-rigid wiring board of the present invention is a flex-rigid wiring board comprising a flex part constituted by a flexible wiring board and a rigid part made of a rigid wiring board connected to the flex part, and the rigid part Includes an insulating layer that sandwiches the end portion of the flexible wiring board, and the insulating layer has an intermediate layer having a thickness that is substantially the same as or slightly thinner than the thickness of the flexible wiring board in a portion that does not sandwich the end portion. The intermediate layer is formed by integrating the insulating layer on both sides by curing the prepreg, and electrically connecting the wiring pattern formed at the end of the flexible wiring board and the wiring pattern of the rigid wiring board. It has the interlayer connection part to perform.

  According to the flex-rigid wiring board of the present invention, the insulating layer sandwiching the end portion of the flexible wiring board has an intermediate thickness that is substantially the same as or slightly thinner than the thickness of the flexible wiring board in the portion that does not sandwich the end portion. Since it has a layer, it becomes easy to make the thickness of a rigid part uniform compared with the case where it does not have an intermediate layer. At that time, since the intermediate layer is formed by curing the prepreg and integrated with the insulating layers on both sides, the gap between the flexible wiring board and the end of the flexible wiring board can be easily filled with resin, and the strength and adhesion can be improved. Can do. In addition, the flex part and the rigid part can be formed by a process of heating and pressurizing and integrating the laminate in which the flexible wiring board is sandwiched from both sides in a laminate unit of the rigid wiring board through the prepreg, so that the flex rigid A wiring board can be manufactured. As a result, it is possible to provide a flex-rigid wiring board in which a substrate with high adhesion between layers can be manufactured by a simple process and the thickness of the rigid portion can be made more uniform.

  In the above, it is preferable that the said intermediate | middle layer has a notch part by which the edge part of the said flexible wiring board is arrange | positioned. Thereby, the level | step difference around the edge part of a flexible wiring board can be made small, and thickness can be equalized in the whole surface of a rigid part.

  Moreover, it is preferable that the said intermediate | middle layer is formed using the prepreg whose fluidity is higher than the prepreg used for formation of the insulating layer which pinched | interposed the said edge part. Thus, by using a prepreg having high fluidity, the filling and entering of the resin are improved, whereby the adhesion of each layer can be further improved.

Process drawing which shows an example of the manufacturing method of the flex-rigid wiring board of this invention Process drawing which shows an example of the manufacturing method of the flex-rigid wiring board of this invention Process drawing which shows the other example of the manufacturing method of the flex-rigid wiring board of this invention Sectional drawing which shows the other example of the flex-rigid wiring board of this invention Process drawing which shows the other example of the manufacturing method of the flex-rigid wiring board of this invention Process diagram showing a conventional flex-rigid wiring board manufacturing method

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the flex-rigid wiring board of the present invention will be described.

  As shown in FIG. 2 (b), the flex-rigid wiring board of the present invention includes a flex part 17 composed of a flexible wiring board 10 and a rigid part 18 composed of a rigid wiring board connected to the flex part 17. Prepare.

  The flexible wiring board 10 has a wiring pattern (not shown) formed on one side or both sides of a flexible insulating base. As the insulating substrate, for example, a polyimide film or a polyester film is used. A coverlay is provided on the surface of the wiring pattern as necessary.

  The rigid wiring board is a wiring board having higher rigidity, and includes an insulating layer 34 made of a cured material such as a prepreg 11, an insulating layer 19, and a wiring layer made of a wiring pattern 23 a and the like. When the rigid wiring board is a multilayer wiring board, a plurality of insulating layers and wiring layers are provided. In the present embodiment, an example in which a rigid wiring board has four wiring layers is shown.

  In the present invention, as shown in FIG. 2B, the rigid portion 18 includes an insulating layer 34 that sandwiches the end portion 10 a of the flexible wiring board 10. The insulating layer 34 has an intermediate layer 33 having a thickness substantially the same as or slightly thinner than the thickness of the flexible wiring board 10 at a portion where the end portion 10a is not sandwiched, and the intermediate layer 33 is formed on both sides of the prepreg 31 by curing. The insulating layer 32 is integrated. The insulating layer 32 is composed of a cured product of the prepreg 11.

  The end portion 10a of the flexible wiring board 10 is preferably sandwiched in a region having a width of 3 to 30 mm, and more preferably a region having a width of 5 to 10 mm. If the width of the end 10a to be sandwiched is less than 3 mm, the connection strength is insufficient, and it is difficult to form an interlayer connection. Conversely, if the width of the sandwiched end portion 10a exceeds 30 mm, the amount of the expensive flexible wiring board 10 used is increased and the cost is increased, and the problem of deformation and peeling due to the difference in thermal expansion coefficient is likely to occur. Tend.

  Further, the thickness of the flexible wiring board 10 is preferably 10 to 250 μm. If the thickness of the flexible wiring board 10 is less than 10 μm, the strength and durability of the flex portion 17 tend to be insufficient, and if the thickness exceeds 250 μm, the difference in thickness from the portion where the flexible wiring board 10 is not sandwiched. This tends to cause poor adhesion and generation of cracks.

  The thickness of the intermediate layer 33 of the insulating layer 34 is substantially the same as or slightly thinner than the thickness of the flexible wiring board 10, and is preferably a thickness of the flexible wiring board 10 + 10% to −20%. More preferably, the thickness is + 5% to −5%.

  In the present invention, the width of the flexible wiring board 10 (the width in the direction perpendicular to the paper surface in FIG. 2) may be the same as or different from the width of the rigid portion 18. When the width of the flexible wiring board 10 is smaller than the width of the rigid portion 18, it is preferable that the intermediate layer 33 has a notch portion in which the end portion 10 a of the flexible wiring board 10 is disposed.

  The intermediate layer 33 of the insulating layer 34 is preferably formed using a prepreg 31 having higher fluidity than the prepreg 11 used for forming the insulating layers 32 on both sides sandwiching the end 10a. The prepreg 11 is preferably a low-flow type in order to reduce the bleeding of the resin toward the flex portion 17 side. However, since the prepreg 31 is not necessary, it is preferable to use a normal prepreg having higher fluidity. .

  In the flex-rigid wiring board of the present invention, the wiring pattern 23a of the rigid portion 18 is conductively connected at the interlayer connection portion to the wiring pattern formed on the end portion 10a of the flexible wiring board 10. In the present embodiment, as shown in FIG. 2B, an example in which the interlayer connection portion is formed by through-hole plating 22 is shown.

  Next, although the manufacturing method of this invention is demonstrated, the flex-rigid wiring board of this invention can be suitably manufactured with the manufacturing method of this invention described below.

  As shown in FIGS. 1A to 1D, the manufacturing method of the present invention heats and pressurizes a laminate in which a flexible wiring board 10 is sandwiched from both sides via a prepreg 11 in a laminate unit of a rigid wiring board. The process of integrating is included. In this embodiment, an example is shown in which a precursor PW (patterned on only one side) of two double-sided wiring boards is used as a laminate unit of rigid wiring boards.

  In this embodiment, first, as shown in FIG. 1A, a double-sided copper-clad laminate in which copper foils 12 are laminated and integrated on both surfaces of an insulating layer 19 and the copper foils 12 are conductively connected to each other at an interlayer connection portion. Prepare. The interlayer connection portion can be formed with, for example, a conductive paste, and after opening an opening in the semi-cured insulating layer 19 by laser processing or the like and filling the opening with the conductive paste, the copper foil 12 is formed. The above double-sided copper-clad laminate can be manufactured by stacking and integrating by heating and pressing. In addition, the interlayer connection portion can be formed by through-hole plating, laser via, filled via, or the like.

  Next, as shown in FIG. 1 (b), the double-sided copper clad laminate at the portion where the flex portion 17 is formed is cut out, and the outer shape of the rigid portion 18 is processed as necessary. These processes can be performed using a router or the like. FIG. 1 (d ′) shows a plan view of a state in which a double-sided copper-clad laminate has been cut out.

  Next, as shown in FIG. 1C, one copper foil 12 is etched or the like to form a wiring pattern 12a, thereby creating a precursor PW of a double-sided wiring board. Etching can be performed after forming an etching resist having a predetermined pattern.

  Next, as shown in FIGS. 1D and 1D ′, the flexible wiring board 10 is sandwiched from both sides through the prepreg 11 so that the wiring patterns 12a face each other, with the rigid wiring board laminated unit. Let it be a laminate. At that time, in the present invention, the prepregs 11 on both sides for bonding the laminated units on both sides sandwich the end 10a of the flexible wiring board 10, and the other part is a laminate having another prepreg 31 sandwiched therebetween. . In the present embodiment, as shown in FIG. 1 (d), an example in which another prepreg 31 has a cutout portion having substantially the same shape as a cutout portion of a double-sided copper-clad laminate. In this example, the rigid portion 18 is finally cut along the cutting line C, and the two rigid portions 18 are formed on both sides of the flex portion 17. Thus, when another prepreg 31 has a cut-out portion and the flexible wiring board 10 is disposed in this cut-out portion, the end side of another prepreg 31 is disposed along the end side of the rigid portion 18 ( Compared with FIG. 5A, the influence of the resin flow is reduced, so that the thickness of the entire rigid portion 18 can be made more uniform.

  The other prepreg 31 preferably has substantially the same thickness as the flexible wiring board 10 or a slightly thinner thickness. Specifically, the thickness of another prepreg 31 is preferably the thickness of the flexible wiring board 10 + 10% to −20%, and more preferably + 5% to −5%.

  The prepreg 11 includes a semi-cured resin that serves as both insulation and adhesion, and is generally a mixture of a thermosetting resin such as an epoxy resin and a curing agent in a reinforcing material made of glass fiber or the like. Is applied to form a semi-cured state (B-stage). Another prepreg 31 may be made of the same material as that of the prepreg 11, but the other prepreg 31 preferably has higher fluidity at the temperature at the time of heating and pressurization than the prepregs 11 on both sides. Specifically, it is preferable to use a low flow type as the prepreg 11 and use a normal prepreg having higher fluidity as the prepreg 31.

  When laminating, for example, the laminate is placed on a lower mirror plate via a release film. It is preferable that the laminate is integrated by placing an upper mirror plate on the release film and heating and pressurizing it.

  When the prepreg 11 and the other prepreg 31 are heated, the resin and the curing agent react with each other inside to temporarily soften the resin portion and then harden, so that the flexible wiring board 10 and the double-sided wiring board While acting as an adhesive to connect the precursor PW, it becomes the insulating layer 34 of the rigid wiring board.

  The heating and pressing conditions depend on the amount of resin and the curing agent forming the prepreg 11, etc., and the type, but when an epoxy resin is used, the temperature is 150 to 350 ° C., preferably 170 to 300 ° C. It is good.

  In the present invention, as shown in FIGS. 2A and 2B, the wiring pattern formed on the end portion 10a of the flexible wiring board 10 and the wiring pattern of the rigid wiring substrate (rigid portion 18) are conductively connected. Forming an interlayer connection. In this step, after the integration, the wiring pattern 23 of the rigid portion 18 is preferably conductively connected to the wiring pattern formed on the end portion 10a by the through-hole plating 22 or the laser via. In the present embodiment, an example in which an interlayer connection portion is formed by through-hole plating 22 is shown.

  In this case, as shown in FIG. 2A, after the through hole (through hole) is formed in the rigid portion 18 with the end portion 10a sandwiched by drilling or punching, the surface of the rigid portion 18 including the through hole is formed. Then, the plating layer 23 is formed by plating. As a plating method, electroless plating or a combination of electroless plating and the like and electrolytic plating is used.

  Next, as shown in FIG. 2B, the plating layer 23 is etched into a predetermined pattern to form a wiring pattern 23a. Thereby, the wiring pattern 23 a of the rigid portion 18 can be conductively connected to the wiring pattern formed on the end portion 10 a of the flexible wiring board 10.

  The rigid portion 18 is formed with precious metal plating or solder resist as necessary. In addition, cutting or external processing by a router or the like is performed as necessary.

[Other Embodiments]
(1) In the above-described embodiment, an example in which an interlayer connection portion is formed by through-hole plating has been shown. However, in the present invention, any method for forming an interlayer connection portion may be used, and as shown in FIG. The wiring pattern 23a of the rigid portion 18 may be conductively connected to the wiring pattern formed on the end portion 10a of the flexible wiring board 10.

  In that case, first, as shown in FIG. 3A, a non-through hole is formed in the rigid portion 18 with the end 10a sandwiched by laser processing, and then the surface of the rigid portion 18 including the inner surface of the non-through hole is formed. The plating layer 23 is formed by plating.

  Next, as shown in FIG. 3B, the plating layer 23 is etched into a predetermined pattern to form a wiring pattern 23a. Thereby, the wiring pattern 23 a of the rigid portion 18 can be conductively connected to the wiring pattern formed on the end portion 10 a of the flexible wiring board 10.

  (2) In the above-described embodiment, a rigid-rigid wiring board having a rigid portion having four wiring layers is manufactured by using a two-sided wiring board precursor and a prepreg as a laminate unit of the rigid wiring board. In the present invention, the number of layers of the rigid portion wiring layer is not limited. For example, as shown in FIG. 4, the rigid portion 18 may be a flex-rigid wiring board having two wiring layers. Good.

  In that case, as a lamination unit of the rigid wiring board, only the prepreg 11 and another prepreg 31 are laminated and integrated, and then laser processing, plating, and etching are performed to form the wiring pattern 23a and the laser via 25. Can do. Also, as a laminate unit of the rigid wiring board, the prepreg 11 and the copper foil are laminated and integrated, and then the through hole is formed, plated, and etched to form the wiring pattern and the through hole plating. It is.

  In addition, when manufacturing a flex-rigid wiring board having a rigid part having four or more wiring layers, a larger number of double-sided wiring boards can be laminated as a laminated unit of the rigid wiring board, or a multilayer wiring board can be used A substrate may be used.

  (3) In the above-described embodiment, the example in which the prepreg and the precursor of the double-sided wiring board are separately stacked has been shown. However, in the present invention, the prepreg is integrated with the precursor of the double-sided wiring board in advance. When laminating, the end of the flexible wiring board and another prepreg may be sandwiched, and the laminate may be integrated by heating and pressing. Further, instead of using the precursor of the double-sided wiring board, the layers constituting them may be laminated as separate bodies, and a laminate obtained by further laminating other members may be integrated by heating and pressing.

  On the contrary, the end portion of the flexible wiring board and another prepreg are sandwiched and integrated in advance with a prepreg, and a precursor of a double-sided wiring board is laminated thereon, and this laminate is heated and pressed to be integrated. Good.

  (4) In the above-described embodiment, an example in which a rigid portion including a plurality of rigid wiring boards is connected to the flex portion has been described. However, in the present invention, at least one rigid portion and at least one flex portion are connected. It only has to be.

  (5) In the above-described embodiment, as shown in FIG. 1 (d ′), another prepreg 31 has an example in which a cutout portion having substantially the same shape as the cutout portion of the double-sided copper-clad laminate is shown. As shown in 5 (a), the shape of another prepreg 31 may have a notch portion having an end side along the cutting line C and in which the end portion 10 a of the flexible wiring board 10 is disposed. That is, the present invention may be implemented in a state where another prepreg 31 does not exist between the cutting lines C and C.

  Further, as shown in FIG. 5B, the end side of another prepreg 31 may be formed linearly along the tip of the end portion 10 a of the flexible wiring board 10. Thus, in the present invention, if the prepreg on both sides for adhering the laminated units on both sides sandwiches the end portion of the flexible wiring board and uses a laminate in which another prepreg is sandwiched between the remaining portions. The shape of another prepreg may be any. However, a shape in which the end portion of the flexible wiring board and another prepreg overlap each other is not preferable.

DESCRIPTION OF SYMBOLS 10 Flexible wiring board 10a End part 11 Prepreg 17 Flex part 18 Rigid part 22 Through-hole plating (interlayer connection part)
23a Wiring pattern 25 Laser via 31 Another prepreg 33 Intermediate layer 34 Insulating layer

Claims (7)

A step of heating and pressurizing a laminate in which a flexible wiring board is sandwiched from both sides in a laminate unit of a rigid wiring board via a prepreg, a wiring pattern formed at an end of the flexible wiring board, and the rigid wiring board A method of manufacturing a flex-rigid wiring board, including a step of forming an interlayer connection portion that conductively connects the wiring pattern of
In the laminate, the prepreg on both sides for adhering the laminated units on both sides sandwiches the end portion of the flexible wiring board, and another prepreg is sandwiched between the remaining portions of the flexible rigid wiring board. Production method.   The method for manufacturing a flex-rigid wiring board according to claim 1, wherein the another prepreg has a cutout portion or a cutout portion for disposing an end portion of the flexible wiring board.   3. The method for manufacturing a flex-rigid wiring board according to claim 1, wherein the another prepreg has higher fluidity at a temperature at the time of heating and pressurization than the prepregs on both sides.   The method for manufacturing a flex-rigid wiring board according to any one of claims 1 to 3, wherein the another prepreg has substantially the same thickness as the flexible wiring board or a slightly thinner thickness. A flex-rigid wiring board comprising a flex part composed of a flexible wiring board and a rigid part made of a rigid wiring board connected to the flex part,
The rigid portion includes an insulating layer that sandwiches the end portion of the flexible wiring board, and the insulating layer has a thickness that is substantially the same as or slightly thinner than the thickness of the flexible wiring board in a portion that does not sandwich the end portion. Having an intermediate layer, the intermediate layer is one in which the prepreg is cured and integrated with the insulating layers on both sides,
A flex-rigid wiring board having an interlayer connection portion for conductively connecting a wiring pattern formed at an end of the flexible wiring board and a wiring pattern of the rigid wiring board.   The flex-rigid wiring board according to claim 5, wherein the intermediate layer has a notch portion in which an end portion of the flexible wiring board is disposed. The flex-rigid wiring substrate according to claim 5 or 6, wherein the intermediate layer is formed using a prepreg having higher fluidity than a prepreg used for forming an insulating layer sandwiching the end portion. Method.

Images