JP2000059032A - Flexible multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible multilayer wiring board of a structure, wherein the miniaturization of the wiring board and an increase in the density of the wiring board are possible and a test on continuity and a check on the operation of a circuit facilitated. SOLUTION: A flexible multilayer wiring board having rigid parts 1 and 2 formed by forming a flexible wiring board in a state, in which the wiring board is formed into a multilayer structure and is hardly bent and a flux part 3 formed by forming the flexible wiring board in a state in which the wiring board is not formed into a multilayer structure and is bendable is one which is characterized by that elements are respectively mounted on the rigid parts 1 and 2, one internal layer in the multilayer of the flexible wiring board is made to expose as the flexible part 3, wiring for wiring connection state verification or circuit operation verification is provided on the flexible part 3 and a check land 4 connected with the wiring is provided on the flexible part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible multilayer wiring board having check lands for checking the connection state of a flexible multilayer wiring board and the operation of a mounted circuit.

[0002]

2. Description of the Related Art Conventionally, many flexible wiring boards are
Single-sided or double-sided printed boards have been the mainstream, but in recent years, further miniaturization and thinning of products have been demanded, and mounting boards for mounting semiconductor elements have also been required to be miniaturized and densified.

As a result, the number of layers has been increased in flexible wiring boards, and multilayer wiring boards having four or six layers have been used.

Also, in checking the continuity of the wiring board and the operation of the mounted circuit, several years before the conventional single-sided or double-sided printed circuit boards were mainstream, check lands for confirming main signals were formed on the boards. They are arranged, checked with an inspection tool via a check land, and defective parts are identified and parts are replaced.

However, in the case of a multilayer wiring board, miniaturization and
In order to cope with higher densities, the check lands have also been abolished, and there has been a shift to no checks and self-checks of operation using ICs such as microcomputers to be mounted. Therefore, in a multilayer wiring board, when an operation failure occurs on a product or a circuit operation becomes defective by a self-check by a mounted microcomputer, it is necessary to replace the board unit itself.

[0006]

However, in order to realize the miniaturization and high density of the wiring board as described above, a shift is made to a non-check in which check lands are abolished or a self-check using a mounted microcomputer or the like. Therefore, if an operation failure is found after the product has been manufactured, it is extremely difficult to identify the defective portion.

Further, even in the self-check, it is impossible to check all signal lines, and the same result as described above is obtained.

Further, even if the malfunction is found, the board unit itself must be replaced, so that an increase in repair cost cannot be avoided.

Also, like a conventional double-sided printed circuit board,
If check lands are arranged in the rigid portion of the flexible multilayer wiring board as the component mounting portion, conflicting results such as the inability to cope with high density will result.

An object of the present invention is to provide a flexible multi-layer wiring board which can be reduced in size and density and which can easily conduct a continuity test and check a circuit operation.

[0011]

According to the present invention, there are provided a rigid portion in which a flexible wiring board is multilayered so as to be hardly bent and a flex portion in which a flexible wiring board is capable of being bent without multilayering. In the flexible multilayer wiring board having the above, an element is mounted on the rigid portion, one of the inner layers in the multilayer is exposed as a flex portion, and a wiring for confirming a connection state or a circuit operation is provided on the flex portion, Since the check land connected to the circuit is provided on the flex portion, the conduction and the operation of the mounted circuit can be checked without increasing the area of the rigid portion restricted by the size of the product.

In addition, the flex portion of the inner layer connects the rigid portions, which are formed by multi-layered flexible wiring boards and does not bend, and the check lands are arranged on the flex portion, so that the bent portion can be effectively used.

Even when there is no connection between the rigid portions, the arms are formed by protruding the inner layer and the check lands are arranged on the flex portions so that the arms can be bent and stored even when assembled into the product. It is possible to do.

Further, even in a product structure having no space for storage, it is also possible to cut only the arm portion having the check land after the checking step and to have only the rigid portion.

Further, since the flex portion of the inner layer is a double-sided substrate and check lands from different signal lines are arranged at the same coordinate position on the front and back surfaces, the number of check lands is increased without increasing the area of the flex portion. Not only can it be possible, but if a check tool that applies check pins from both directions from the front side and back side at the time of checking, it is possible to increase the number of checks at the same time without using a check tool with a check pin receiving part on the flex part Signal can be checked.

[0016]

Embodiments of the present invention will be described below.

(First Embodiment) FIG. 1 is a perspective view showing a component mounting state of a flexible wiring board according to a first embodiment of the present invention.

Reference numerals 1 and 2 denote rigid portions having a flexible wiring board having a multi-layered structure which is hardly bent. On the rigid portion 1, a ball grid array (abbreviated as "BGA") type microcomputer 5 is provided. The peripheral IC 8, the bypass capacitor 7, and other unillustrated electric components are also densely mounted on the rigid portion 2, respectively. I have.

Reference numeral 3 denotes a bendable flex portion comprising the inner layers of the rigid portions 1 and 2, which is formed of a single-sided or double-sided pattern. Wiring for checking the conduction state or circuit operation is provided on the flex portion, and the rigid portions 1 and 2 are electrically connected by patterning (not shown).

Reference numeral 4 denotes a check land connected to a wiring for confirming the conduction state of each signal line of the rigid portions 1 and 2 and a circuit operation, and is used for patterning (not shown) from main signal terminals of the rigid portions 1 and 2. Check land 4a
To 4n.

A check pin of an inspection tool for checking the continuity state and the circuit operation state is applied to the check lands 4a to 4n, and the continuity state and the circuit operation of each signal line of the rigid parts 1 and 2 are checked. Is determined as non-defective. At this time, even if it is determined that the component is defective, the defective part is easily extracted, so that the defective component can be replaced immediately.

FIG. 2 is a cross-sectional view showing a state in which the flexible wiring board on which the electric parts shown in FIG. 1 are mounted is checked and assembled into a product, and the flex parts 3 are arranged so that the rigid parts 1 and 2 are opposed to each other. Is folded and incorporated as shown in FIG.

(Second Embodiment) FIG. 3 is a perspective view showing a state in which components are mounted on a flexible wiring board according to a second embodiment of the present invention.

In the figure, reference numeral 10 denotes a rigid portion having a structure in which a flexible wiring board is multilayered and does not bend.
0 is a BGA type microcomputer 13
Also, the bypass capacitor 14 and other electric components (not shown) are mounted and arranged at high density.

Reference numeral 11 denotes an inner layer of the rigid portion 10,
A protruding arm portion, which is a flex portion having a single-sided or double-sided pattern. Reference numeral 12 denotes a check land for checking the continuity of each signal line of the rigid portion 10 and the circuit operation, and is connected to 12a to 12n from main signal terminals of the rigid portion 10 by patterning (not shown). ing.

The check pins of the inspection tool are applied to the check lands 12a to 12n, and the continuity of each signal line of the rigid portion 10 and the circuit operation are checked. At this time, even if it is determined to be defective, the defective part can be easily extracted, so that the defective part can be replaced immediately.

FIG. 4 is a view showing a state in which the flexible multilayer wiring board on which the electric parts of FIG. 3 are mounted is checked and assembled into a product, and is arranged in a product case 15 as shown in FIG. The flex portion 11 is bent at 90 degrees and mounted and arranged in an empty space in the case. Further, the rigid portion is fixed to the case by screwing and fixing to a substrate receiving portion protruding from a case (not shown).

FIG. 5 is a view showing a state in which a flexible wiring board on which electric components are mounted is incorporated in a product, similarly to FIG. 4, but shows a case where the product is further downsized.

Reference numeral 16 denotes a product case, which is smaller than the product case 15 shown in FIG. 4, and has no space for accommodating the flex portion of the flexible wiring board on which electric components are mounted.

In such a case, the continuity of each signal line and the circuit operation are checked by the inspection tool, and after the non-defective product is judged, the broken line AA ′ shown in FIG. Can be mounted and arranged as follows.

(Third Embodiment) FIG. 6 is a view showing a state where components are mounted on a flexible printed circuit board according to a third embodiment of the present invention and a check is performed by an inspection tool.

In the figure, reference numeral 20 denotes a rigid portion in which the flexible wiring board is multilayered and does not bend.
A BGA type microcomputer 23, a bypass capacitor 24, and other electric components (not shown) are mounted and arranged at high density.

Reference numeral 21 denotes an inner layer of the rigid portion 20,
The protruding arm portion is a flex portion composed of a double-sided pattern.

FIG. 7 is a diagram showing the flex portion of FIG.

FIG. 7A shows a flex portion as viewed from the surface as an element mounting surface, in which check lands 22 including 22a to 22n are arranged. FIG. 7B shows a flex portion viewed from the back surface, in which check lands 32 including 32a to 32n are arranged. As can be seen from this figure, the same number of n check lands are arranged as the front and back sides, and
Check land 22 on the front and check land 3 on the back
2 is disposed at the same coordinate position on the front and back sides, and is connected to each of main different signal terminals from above the rigid part 20 by patterning (not shown).

In FIG. 6, check pins 25 and 26 are attached to a check tool, are joined to check lands of a flexible wiring board, and check the continuity of each signal line and the circuit operation.
Is composed of the same number of n check pins as the check lands 22a to 22n on the surface of the flex portion, moves in the direction of arrow B in the drawing, and is joined to the check lands by pressure.

Similarly, the check pin 26 is composed of the same number of n check pins as the check lands 32a to 32n on the back surface of the flex portion, moves in the direction of arrow C in the drawing, and is pressure-bonded to the check lands.

At this time, the check pins 25 and 26 are pressure-bonded at the same time at the same pressure, and are configured to maintain a balanced state. Therefore, it is not necessary to provide a special check pin receiving portion in the flex portion.

[0039]

As described above, claims 1 to 3 are described.
According to the present invention described in the above, in the flexible multilayer wiring board having a flexible portion in which the flexible wiring board is multilayered and does not bend, and a flexible portion in which the flexible wiring board is not multilayered and which can be bent, any one of the multilayer Since the inner layer is taken out as a flex portion and check lands are arranged on the flex portion, the bent portion can be effectively used without increasing the area of the rigid portion restricted by the size of the product, and the product can be reduced in size. In addition to being able to cope with thinning and thinning, it is possible to easily check the conduction on the flexible wiring board and the operation of the mounted circuit.

According to the fourth aspect of the present invention, the flex portion of the inner layer is a double-sided substrate, and check lands from different signal lines are arranged at target positions on the front and back surfaces. Not only can the number be increased without increasing the area of the flex part, but also if the check tool is used to apply check pins from both the front and back sides when checking, the check pin receiving part on the flex part It is possible to check many signals at the same time without using a check tool with

Further, according to the present invention, it is easy to specify and repair a defective portion, and it is not necessary to replace the board unit itself, so that an increase in repair cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which components are mounted on a flexible multilayer wiring board according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a state in which the flexible multilayer wiring board of FIG. 1 is incorporated in a product.

FIG. 3 is a perspective view showing a state in which components are mounted on a flexible multilayer wiring board according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a state in which the flexible multilayer wiring board of FIG. 3 is incorporated in a product.

FIG. 5 is a sectional view showing a state in which the flexible multilayer wiring board of FIG. 3 is incorporated in a product.

FIG. 6 is a view showing a state where components are mounted on a flexible multilayer wiring board according to a third embodiment of the present invention and checked by an inspection tool.

7A and 7B are diagrams showing the flex portion of FIG. 6, wherein FIG. 7A is a plan view as viewed from the front surface, and FIG. 7B is a plan view as viewed from the back surface.

[Explanation of symbols]

 1, 2 Rigid part 3 Flex part 4 Check land 5 Microcomputer 25, 26 Check pin

Claims (4)

[Claims] 1. A flexible multilayer wiring board having a rigid portion in which a flexible wiring board is multilayered to be hardly bent and a flex portion in which the flexible wiring board is bent without being multilayered. The device is mounted on the device, and any one of the inner layers in the multilayer is exposed as a flex portion, a wire for checking a connection state or a circuit operation is provided on the flex portion, and a check land connected to the wire is provided on the flex portion. A flexible multilayer wiring board characterized by the above. 2. The flex portion of the inner layer is connected to a rigid portion in which a flexible wiring board is multilayered to make it hard to bend, and a check land is provided on the flex portion. 3. The flexible multilayer wiring board according to item 1. 3. The flex portion of the inner layer is an arm portion protruding from a rigid portion in which a flexible wiring board is multilayered to make it hard to bend, and a check land is provided on the flex portion. Item 2. A flexible multilayer wiring board according to item 1. 4. The flexure of the inner layer is a double-sided substrate, and check lands from different signal lines are provided at the same coordinate position on the front surface and the back surface. 13. The flexible multilayer wiring board according to the above item.