JPH06252562A - Multilayered circuit board - Google Patents

Abstract

PURPOSE:To reinforce the adherence strength between an edge electrode and the edge of a multilayered circuit board and to prevent peeling by providing a conductor layer, which is held between at least two insulating layers, and providing the edge electrode, which is deposited on the edge in the curved state, and reinforcing conductors, which are provided on the conductor layer and connected to only the edge electrode. CONSTITUTION:A multilayered circuit board 1 is formed by laminating four insulating layers 4 1a-1d. Reinforcing conductors 5a and 5b are provided on conductor layers 1f and 1h, respectively. The reinforcing conductors 5a and 5b are provided in the arc belt shape along a semi-circular groove, on which an edge electrode 3 is deposited. The inner surface of the arc belt is connected to the edge electrode 3. All outer surface is insulated from the inner circuit conductor. The reinforcing conductors 5a and 5b are provided so as to obtain mechanical connection with the edge electrode 3 and do not function electrically. The reinforcing conductors 5a and 5b are formed by plating or baking in the same step as for the inner circuit conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer circuit board structure suitable for use in a surface mount type circuit block.

[0002]

2. Description of the Related Art FIG. 3 is an external view of a surface mounting type circuit block 10. In FIG. 3, 6 is a multilayer circuit board, and 11 is a metal shield case that covers one surface of the multilayer circuit board 6. The shield case 11 is electrically connected and mechanically fixed to the ground electrode 2 attached to the end surface of the multilayer circuit board 6 by plating or baking with solder 12.

FIG. 4 is a perspective view of the multilayer circuit board 6. The multilayer circuit board 6 is formed by laminating four insulating layers 6a to 6d, and is provided with a ground electrode 2 and an end surface electrode 3 which are attached in a curved shape by plating or baking on a part of the end surface.
Each of the ground electrode 2 and the end surface electrode 3 is an electrode for external connection used as a terminal for connecting the circuit block 10 to an external circuit electrode on a mother board (not shown).

FIG. 5 is a sectional view of the multilayer circuit board 6. In FIG. 5, the upper and lower surfaces of the multilayer circuit board 6 and 4
Conductor layers 6 are provided between the insulating layers 6a to 6d, respectively.
e to 6i are provided, and internal circuit conductors 4a to 4h are formed on the respective conductor layers 6e to 6i. The internal circuit conductors 4a and 4b are connected to the end face electrode 3,
The internal circuit conductors 4c to 4h are connected to the ground electrode 2.

[0005]

When the circuit block 10 is soldered and connected to the external circuit electrode on the mother board, the end face of the multilayer circuit board G is relatively rough and has a small area. 2 and the end face electrode 3 are easily peeled off by the heat of soldering. Even after soldering and connection, stress is applied to the ground electrode 2 and the end face electrode 3 when the mother board expands and contracts in response to changes in temperature and humidity, and these electrodes 2 and 3 are easily peeled off from the end face of the multilayer circuit board 6. There is a problem. In particular, like the end surface electrode 3 in FIG. 5, the internal circuit conductors 4a and 4b connected to each other are connected.
The problem is large in the electrode having a small number of.

For this reason, in the conventional multilayer circuit board 6, the end surfaces to which the ground electrode 2 and the end surface electrodes 3 are adhered are formed in a curved shape to increase the area of the electrodes 2 and 3 and to increase the size of the electrodes 2 and 3.
Even if a part of the electrode is peeled off, the peeled electrode is prevented from rising from the end face. However,
The electrode was easily peeled off from the end face due to the stress. As described above, in the surface-mounting type circuit block 10 using the conventional multilayer circuit board 6, the electrodes for external connection are easily peeled off even when the circuit block 10 is manufactured and after the circuit block 10 is mounted on the motherboard. Is something
The present invention solves these problems.

[0007]

In order to solve the above problems, a multilayer circuit board according to the present invention comprises a conductor layer sandwiched between at least two insulating layers and is curvedly attached to an end face. And an end face electrode and a reinforcing conductor provided on the conductor layer and connected only to the end face electrode.

[0008]

The reinforcing conductor is held by being sandwiched between the insulating layers, and the end face electrode is attached to the end face of the multilayer circuit board and connected to and held by the reinforcing conductor. Therefore, in each conductor layer,
The end face electrode can be held by at least one of the internal circuit conductor and the reinforcing conductor.

[0009]

FIG. 2 is a sectional view of a multilayer circuit board 1 which is an embodiment of the present invention. The multilayer circuit board 1 has four insulating layers 1a.
To 1d are laminated to form upper and lower surfaces and insulating layers 1a.
Conductor layers 1e to 1i are respectively provided between 1 to 1d. This multilayer circuit board 1 differs from the conventional multilayer circuit board 6 shown in FIG. 5 in that conductor layers 1f and 1h are provided with reinforcing conductors 5a and 5b, respectively. Appearance and ground electrode 2, end face electrode 3,
Since the internal circuit conductors 4a to 4h are the same as those of the multilayer circuit board 6, the same reference numerals as those of the multilayer circuit board 6 are given and detailed description thereof is omitted.

Next, the reinforcing conductors 5a and 5b will be described by breaking away the essential part of the multilayer circuit board 1 in FIG. FIG. 1 shows a multilayer circuit board 1 in which a part of the insulating layer 1a is broken. For convenience of explanation, internal circuit conductors 4a to 4h
Is omitted.

The reinforcing conductors 5a and 5b are the conductor layers 1 respectively.
In f and 1h, they are provided in the shape of an arc along the semicircular groove to which the end face electrode 3 is adhered. The inner circumference of the arcuate band is connected to the end face electrode 3, and the outer circumference is insulated from the internal circuit conductors. The reinforcing conductors 5a and 5b are different from the internal circuit conductors 4a to 4h in that they are provided only along the end face electrode 3 and are connected only to the end face electrode 3. That is, the reinforcing conductors 5a and 5b are the end surface electrodes 3
It is provided for the purpose of mechanically connecting to, and does not function electrically. These reinforcing conductors 5a,
5b is the same process as the internal circuit conductors 4a to 4h,
It is formed by plating or baking.

Although the reinforcing conductors 5a and 5b are connected to the end face electrode 3 in the above description, the reinforcing conductors 5a and 5b are not limited to the end face electrode 3 and may be connected to the ground electrode 2 if necessary. good. In addition, the end surface electrode 3 or the ground electrode 2 is not always required.
It is not necessary to provide the reinforcing conductors 5a and 5b on all the conductor layers which are not connected to the internal circuit conductors 4a to 4h.

[0013]

According to the present invention, the end face electrode provided on the end face of the multilayer circuit board can be held by at least one of the internal circuit conductor and the reinforcing conductor in each conductor layer. By providing a reinforcing conductor, the adhesion strength between the end face electrode and the end face of the multilayer circuit board is supplemented, and even if the end face electrode is not in close contact with the end face, the end face electrode is held in each conductor layer, and substantially adheres. It is kept in a state and does not peel off. Therefore, the heating temperature and heating time during soldering have a wide allowable range, soldering is easy, and it is strong against external stress even after soldering, and practical problems do not occur easily. To be

[Brief description of drawings]

FIG. 1 is a fragmentary cutaway view of a multilayer circuit board according to the present invention.

FIG. 2 is a sectional view of a multilayer circuit board according to the present invention.

FIG. 3 is an external view of a circuit block.

FIG. 4 is an external view of a multilayer circuit board.

FIG. 5 is a cross-sectional view of a conventional multilayer circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer circuit board 1a, 1b, 1c, 1d Insulating layer 1e, 1f, 1g, 1h, 1i Conductor layer 2 Grounding electrode 3 End surface electrode 5a, 5b Reinforcing conductor

Claims (1)

[Claims] 1. A multi-layer circuit board comprising a conductor layer sandwiched between at least two insulating layers, the end surface electrode being curvedly attached to an end surface of the multi-layer circuit board, and provided on the conductor layer. And a reinforcing conductor connected only to the end face electrode.