JPS62174996A - Rigid-flexible wiring board and manufacture of the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a rigid/flexible wiring board which is made partially flexible by fixing a rigid board to a flexible board, and its manufacture. It is about the method.

(Prior Art) Rigid-flexible wiring boards are bent at their exposed flexible portions, and are being used more frequently as various products become smaller. In other words, this type of rigid/flexible wiring board has become indispensable for storing and mounting various electronic components within a limited space.

By the way, a conventional rigid/flexible wiring board is as shown in FIG. This conventional rigid
The flexible wiring board (30) is shown bent at the exposed portion (31a) of the flexible circuit board (31), but with one flexible circuit board (31) at the center, one or both sides of the flexible circuit board (30) are bent. By fixing the rigid substrate (32), a part of the flexible substrate (31) is exposed to form an exposed portion (:1la). In this conventional rigid/flexible wiring board (30), the edge (32a) of each rigid board (32) located near the exposed portion (11a) is It is formed as. Therefore, when the rigid/flexible wiring board (30) is bent into the state shown in FIG.
) will come into direct contact with the flexible substrate (31) or the conductor layer (3) formed on its surface.

In this way, the end (32a) of each rigid board (32)
If the right-angled portion of the flexible substrate (31) or the conductor layer (33) formed on the surface of the flexible substrate (31) comes into direct contact with the flexible substrate (31), the following negative effects may occur.

That is, since the conductor layer (33) formed on the flexible substrate (31) side is for conducting electricity to each substrate, the hard rigid substrate (33) is connected to this conductor layer (33).
If the ends (12a) of 2), particularly the right angle portions, come into contact, this conductor layer (33) may be damaged, thereby inhibiting conduction.

It may be the exposed part of this flexible board (31) (
31a) is likely to be bent many times during the mounting of electronic components, and if such bending is repeated, the problems mentioned above will become noticeable. Even if the conductor layer (3) is not formed on the flexible substrate (31), a similar situation will result in damage to the flexible substrate (31) itself, which connects each substrate. So, it's bound to become a problem.

In addition, in manufacturing such a conventional rigid/flexible wiring board [30], a flexible board (31
) After fixing each rigid board (32) to the rigid board (32), a conductor circuit is formed on the surface of the rigid board (32) by etching, plating, etc., but the etching liquid, plating liquid, etc. used in this case are Flexible board (3
1) and the end (32a) of the rigid substrate (32). This accumulated etching solution, plating solution, etc. may have an adverse effect on other parts after the rigid/flexible wiring board (30) is completed, so it is necessary to completely remove it. Another process such as washing with water is required, and the liquid must also be treated.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances. It is easy to use, and it is also inefficient in manufacturing rigid/flexible wiring boards.

First of all, it is an object of the present invention to provide a rigid-flexible wiring board having a structure that can easily avoid damage at bent portions of this type of rigid-flexible wiring board. . The second object is to provide a method that can easily manufacture this type of rigid/flexible wiring board.

(Means for solving the problems) What are the means taken by the first invention to solve the above problems?

A flexible board (11) and this flexible board (
11) and a rigid substrate (12) that exposes a part of the flexible substrate (11).
) is a rigid/flexible wiring board (lO) formed with conductor circuits formed at necessary locations on the flexible substrate (11), at the end of each rigid substrate (11) close to the exposed portion of the flexible substrate (11). 1
Steps (12a) are formed that become thinner in sequence toward the exposed portion (lla) of 1), and the bent portion of the flexible substrate (11) is held between the thinnest parts of these steps (12a). This is a rigid/flexible wiring board (10) characterized in that: The second invention as a method for manufacturing such a rigid/flexible wiring board is a method for manufacturing a rigid/flexible wiring board comprising the following steps.

(a) Exposed portion of flexible substrate (11) [ ], ll
Step of forming a groove (12b) corresponding to the portion a on the inside of the rigid substrate (12); (b) bonding sheet to the flexible substrate (11) - (1,
4) Step of laminating and adhering the rigid substrate (12) so that the groove (izb) faces the flexible substrate (11) via: (c) Forming a conductor circuit on the surface side of each rigid substrate (12), etc. (d) Cutting the rigid substrate (12) along the groove (12b) to form a step (12a) at the end of the rigid substrate (12),
This is a step of exposing the exposed portion (lla) of step 11).

(Actions of the Invention) By adopting the above measures, the present invention has the following effects.

First, the rigid/flexible wiring board (1
0), since the stepped portion (12a) is formed at the end of each rigid substrate (12) corresponding to the exposed portion (Ila) of the flexible substrate (11), this rigid substrate (12) The bent portion of the flexible substrate (11) is held between the two. Since each step (12a) sandwiching the bent part of the flexible substrate (11) is the thinnest part, even if the rigid substrate (12) is made of a material with high strength, The step part (12
The thinnest part a) has some degree of flexibility. Therefore, when the flexible substrate (11) is bent, each step (12a) sandwiching the bent portion of the flexible substrate (11) elastically supports the bent portion. It will become.

Therefore, the bent portion of the flexible substrate (11) or the conductor formed there! (13) is supported elastically, so even if the flexible substrate (11) is frequently bent, there is no influence from the ends of each rigid substrate (12).

Furthermore, when the rigid/flexible wiring board (10) is manufactured by the method according to the present invention, the rigid board (
Since the exposed portion (lla) of the flexible substrate (11) is formed after the conductor layer (13) is formed on the surface of the rigid substrate (12) by etching and plating, the conductor layer (13) is formed on the surface of the rigid substrate (12). ) The etching solution, plating solution, etc. used when forming the layer (1La) do not remain in the vicinity of the exposed portion (lLa) at all. Therefore, the rigid
The flexible wiring board (10) is not adversely affected by the etching solution, plating solution, etc., especially in the vicinity of the exposed portion (lla) of the flexible substrate (11).

(Example) Next, each invention will be described in more detail based on an example shown in two drawings.

FIG. 1 shows a longitudinal cross-sectional view of a rigid-flexible wiring board (10) according to the present invention. This rigid-flexible wiring board (1 unit) consists of a flexible flexible board (11) placed in the center, and a plurality of boards fixed to both sides of the flexible board (1) via adhesive sheets (14). It is mainly composed of a rigid substrate (12).

The flexible board (11) is connected to each rigid board (12)
The exposed part (
Ila) is formed. And this exposed part (1
There is a stepped portion (1a) at the end of each rigid board (12) on the 1a) side.
2a) is the formation.

Since the stepped portion (12a) is for elastically supporting the bent portion of the flexible substrate (11), it may be simply thin as shown in FIG. (lla) may have a shape that gradually slopes toward the center. Further, as shown in FIG. 5, the stepped portion (12a) may be formed in a stepped manner so as to become gradually thinner.

In addition, each flexible board (11) and rigid board (
12) has a conductor layer (13) formed as necessary;
Electronic components (not shown) are mounted on the surface of each rigid board (12). These flexible substrates (11) and rigid substrates (12) are fixed to each other by an adhesive sheet (14) interposed between them. Of course, the exposed portion of the flexible substrate (11) (
An opening (14a) is formed in a portion of the adhesive sheet (14) corresponding to lla).

As this adhesive sheet (14), it is preferable to use a glass cloth impregnated with a non-tiLqjJ semi-curable resin.

By this adhesive sheet (14), the flexible substrate (1
1) and the rigid substrate (12) are bonded to each other,
A part of this adhesive sheet (14) is prevented from flowing into the opening (14a), and the rigid substrate (
This is to prevent a part of the flexible substrate (12) from being adhered to the flexible substrate (11) side. Also, adhesive sheet (14)
If a fluid material must be used as a flexible substrate, attach each rigid substrate (12) to the flexible substrate (11).
Before bonding, an opening (14a) is formed in advance in a portion corresponding to the exposed portion of the flexible substrate (11), and a release material having the same thickness as the adhesive sheet (14) is applied to the flexible substrate (11). It is preferable to interpose it in the opening (14a).

This is to prevent a part of the rigid substrate (12) to be removed later from being adhered to the flexible substrate (11) by using a release material having the same thickness as the adhesive sheet (14).

Further, as a material for forming each of the above-mentioned flexible substrates (11), the following materials may be used. That is, materials suitable for the flexible substrate (11) include phenol resin, unsaturated polyester resin, epoxy resin, and polyimide resin.

Triazine resin, polybutadiene resin, fluorine-based HA
＠, polysulfone resin alone, or a modified product or a mixture thereof.

On the other hand, as a material for forming the above-mentioned rigid substrate (12), the following materials may be used. In other words, materials suitable for this rigid substrate (12) include phenol resin, unsaturated polyester resin, epoxy resin, polyimide resin, triazine resin, polybutadiene resin, fluorine resin, polysulfone resin, or modified materials thereof. materials or mixtures, or ceramics.

Next, a method according to the present invention for manufacturing this rigid-flexible wiring board (■0) will be explained with reference to FIGS. 2 and 3. This method consists of the following steps. That is, (a) forming a groove portion inside the rigid substrate corresponding to the exposed portion of the flexible substrate; (b) forming the rigid substrate on the flexible substrate via an adhesive sheet so that the groove portion faces the flexible substrate; Step of laminating and bonding: (C) Process of performing various processing such as forming a conductor circuit on the front side of each rigid board: (d) Cutting along the groove of the rigid board to form a step at the edge of the rigid board. In this step, the exposed portion of the flexible substrate is exposed.

The purpose of forming the groove (12b) in the portion of the rigid substrate (12) corresponding to the exposed portion (Ila) of the flexible substrate (ti) is when forming a conductive circuit on the surface of the rigid substrate (12). The etching solution, plating solution, etc. used for
la) This is to prevent it from staying in the vicinity. That is, after the conductor circuit is formed on the surface of the rigid substrate (12), the exposed portion (!la) is exposed for the first time by cutting the rigid substrate (12) along the groove (izb).

Various shapes can be considered for this groove (12b), but it is sufficient as long as the step (12a) of the rigid board (12) described above can be used as a resilient clamping part. It may be triangular as shown in , or may be square or arcuate.

Each rigid board (
12) are fixed to both surfaces of the flexible substrate (11) via each adhesive sheet (14). Of course, the openings (1
4a) is preferably formed. Without this opening (14a), when the portion corresponding to the stepped portion (12a) of each rigid substrate (12) is cut, the portion of each rigid substrate (12) that is removed by the cutting would be covered by the remaining adhesive sheet (14). 12) because it is difficult to separate from it.

After doing the above, various processes such as necessary conductor circuit formation are performed on the front side of each rigid board (12). The etching solution, plating solution, etc. used in this case are
Since the portion of each rigid substrate (12) that faces the exposed portion (lla) of the flexible substrate (11) remains, it does not flow into the vicinity of the exposed portion (lla).

After forming the necessary conductor circuits and the like on the surface of each rigid substrate (12) in this manner, portions corresponding to the respective grooves (12b) are cut from the surface side of each rigid substrate (12). This cutting does not need to be performed to cover the thickness of the rigid substrate (12). Each groove (12b) is connected to each rigid board (1
2), so cut inward of the rigid board (12) by an amount equal to the thickness of the rigid board (12) minus the depth of this groove (12b). Bye. That is, the purpose of this cutting is to remove unnecessary portions of the rigid substrate (12).Next, the present invention will be explained by way of an example.

Example 1 A single-sided substrate was used as the flexible substrate (11), that is,
A double-sided board and a three-layer board were used as the rigid board (12), with a conductor layer formed only on the - side. As the base material of this rigid substrate (12), a glass cloth base material impregnated with polyimide resin was used. Then, a V-shaped groove (this becomes a groove part (12b)) shallower than each board thickness was formed in each rigid substrate (12).

Each of these rigid substrates (12) is covered with an adhesive sheet (1) made of non-flow type prepreg and having a thickness of 40 gm.
4) One sheet of Nikkan Kogyo (product name: 5AF) was interposed and fixed by adhering to the flexible substrate (11). In this case, the exposed portion (1
An opening (14a) was formed in the portion of the adhesive sheet (14) corresponding to 1, a), and Tetra manufactured by DuPont was used as a release paper for this opening (14a). 8 in this case
The single layer conditions were a temperature of 150° C. and a pressure of 20 kg/crn' for about 40 minutes.

After completing the lamination as described above, the necessary through holes are inserted into each flexible board (11) and rigid board (12).
), and a necessary conductor layer was formed on the surface side of each rigid substrate (12).

Thereafter, cutting along a portion corresponding to each groove (tzb) was performed using a normal cutting tool, as shown in FIG. The cutting depth in this case is for each rigid board (12
), and the cross-sectional shape of the cut hole was approximately U-shaped.

Example 2 Each flexible board (11) and rigid board (12)
form. In this case, the base material for the flexible board (11) is Kabuton (polyimide material) manufactured by DuPont, and the base material for the rigid board (12) is a glass cloth base material impregnated with polyimide resin. In addition, as the adhesive sheet (14), Vyralux (trade name, manufactured by DuPont) was used.

The steps from this step to corresponding to each groove portion (12b) and cutting a portion of the JID substrate (12) are the same as those in Example 1 described above, and will therefore be omitted. In this embodiment, the method of cutting each groove (12b) is different. That is, the surface of the rigid substrate (IZ) corresponding to each groove (12b) is first cut a second time with a thicker surface. After that, a second cutting, which is smaller than the first cutting, is performed.

As shown in FIG. 5, this second cutting is performed a little deeper than the -th cutting. As a result, the shape of the stepped portion (12a) of each rigid substrate (12) for elastically supporting the exposed portion (lla) of the flexible substrate (11) can be formed to be extremely thin. I was able to do it.
This allows each step (12a) to have even more elasticity.

(Effects of the Invention) As detailed above, the present invention is as exemplified in each of the above embodiments.

A flexible board (11) and this flexible board (
11) to expose a part of the flexible substrate (11), and each of these flexible substrates (II) and rigid substrates (12)
) is a rigid/flexible wiring board (30) formed with conductor layers formed at necessary locations on the flexible substrate (11), at the end of each rigid substrate (11) near the exposed portion of the flexible substrate (11). 1
Stepped portions (12a) are formed that become thinner in sequence toward the exposed portion (lla) of 1), and the bent portion of the flexible substrate (11) is held between the thinnest portions of these stepped portions (12a). Due to this feature, it is possible to provide a rigid/flexible wiring board (10) having a structure in which damage at the bent portion can be easily avoided.

That is, at the end of each rigid substrate (IZ), there is a stepped portion (+2a) toward the exposed portion (1, la) of the flexible substrate (1'1). By simply forming the flexible substrate (11
) can be supported more elastically than conventional ones, so even if the flexible substrate (11) is bent many times, the rigid/flexible The wiring board (10) is a flexible board (1
1) It is possible to prevent damage to itself and the conductor layer (]3) formed thereon.

In addition, the rigid/flexible wiring board (1
The manufacturing method of 0) is as follows: (a) Exposed portion (lla) of flexible substrate (It)
Place the groove (+2b) corresponding to the part on the rigid board (
(b) Forming the adhesive sheet (14) on the flexible substrate (11)
(c) Forming a conductive layer on the surface side of each rigid board (2) Process of performing various processing; (By cutting along the grooves (+, 2b) of the rigid board (2), a stepped part (12a) is formed at the end of the rigid board (12), and a flexible It is characterized in that it consists of each step of exposing the exposed portion (eye a) of the board (11), and as a result, the rigid/flexible wiring board (10) having the above-mentioned effects can be manufactured in a uniform manner and reliably. There are 'C's that can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a rigid/flexible wiring board according to the present invention, FIG. 2 is an exploded perspective view of each member for explaining the method of manufacturing a rigid/flexible wiring board according to the present invention, and FIG. 3 is a vertical sectional view corresponding to FIG. 1 showing the state before cutting the part corresponding to the groove, and 4+1 is the 3rd
FIG. 5 is an enlarged vertical cross-sectional view of a portion taken along the line (■-IV) in the figure, FIG. 5 is an enlarged vertical cross-sectional view IA corresponding to FIG. 4, and FIG. 6 is a vertical cross-sectional view of a conventional rigid-flexible wiring board. Symbol Lingming IO... Rigid/Flexible wiring board, II...
Flexible substrate, 11. a...Exposed part, 12.
...Rigid board, 12a...Step part, 12b...
・Groove portion, 13... Conductor layer, 14... Adhesive sheet,
L4a...Opening.

Claims (1)

[Claims] 1) Consisting of a flexible substrate and a rigid substrate fixed to the flexible substrate to expose a part of the flexible substrate, conductive circuits are formed at necessary locations on each of the flexible substrate and the rigid substrate. A rigid/flexible wiring board comprising: forming a stepped portion that becomes thinner in sequence toward the exposed portion of the flexible substrate at an end of each of the rigid substrates close to the exposed portion of the flexible substrate; A rigid/flexible wiring board characterized in that the bent portion of the flexible substrate is sandwiched between the thinnest portions of the rigid substrates. 2) The flexible substrate is formed from a phenol resin, an unsaturated polyester resin, an epoxy resin, a polyimide resin, a triazine resin, a polybutadiene resin, a fluorine resin, a polysulfone resin, or a modified product or a mixture thereof. The rigid/flexible wiring board according to claim 1, characterized in that: 3) The rigid substrate is made of phenol resin, unsaturated polyester resin, epoxy resin, polyimide resin, triazine resin, polybutadiene resin, fluorine resin,
The rigid/flexible wiring board according to claim 1 or 2, characterized in that it is formed of polysulfone resin, a modified product or mixture thereof, or ceramics. 4) The rigid-flexible wiring board according to any one of claims 1 to 3, wherein the flexible substrate and the rigid substrate each have one or more conductor layers. 5) A method for manufacturing a rigid/flexible wiring board comprising the following steps. (a) forming a groove portion corresponding to the exposed portion of the flexible substrate inside the rigid substrate; (b) attaching the rigid substrate to the flexible substrate via an adhesive sheet so that the groove portion faces the flexible substrate (c) A step of performing various processing such as forming a conductor circuit on the front side of each of the rigid substrates; (d) A step of laminating and bonding the rigid substrates by cutting along the grooves of the rigid substrates; forming a step at an end of the substrate and exposing the exposed portion of the flexible substrate; 6) The adhesive sheet has an opening formed in advance in a portion corresponding to the exposed portion of the flexible substrate before laminating each rigid substrate on the flexible substrate, and has the same thickness as the adhesive sheet. 6. The manufacturing method according to claim 5, wherein a mold release material is interposed within the opening. 7) The manufacturing method according to claim 5, wherein the adhesive sheet is a glass cloth impregnated with a non-flowable semi-hardened resin.