JPS5915094Y2 - multilayer printed wiring board - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a connection structure between conductor layers in a multilayer printed wiring board.

Conventionally, the connection between the lower layer conductor and the upper layer conductor in a multilayer printed wiring board is performed using insulators 3 and 4 made of cross glass or the like that insulate and protect the lower layer conductor 2 provided on the surface of an insulating substrate 1, as shown in FIG. The exposed portion 2a of the lower conductor 2 was provided by locally removing the two layers, and the upper conductor 5 was printed and wired from above, and the exposed portion 2a of the lower conductor 2 was connected to the upper conductor 5.

For this reason, the drop step distance X between the exposed portion 2a, which is the connecting portion of the lower layer conductor 2, and the upper layer conductor 5 increases, and the conductor film thickness at the arrow A portion in the figure tends to become locally extremely thin.
There was a drawback that the conductor was disconnected at the arrow A portion.

The object of the present invention is to eliminate the above-mentioned drawbacks and provide a multilayer printed wiring board having a structure in which the lower layer conductor 2 and the upper layer conductor 5 are reliably connected.

The following is a second example showing a multilayer printed wiring board according to the present invention.
This will be explained in detail based on the figures.

1 is an insulating substrate.

2 is a lower layer conductor printed and wired on the surface of the insulating substrate 1.

2a is an exposed portion of the lower conductor 2 where the insulators 3 and 4 are not formed.

3 is an insulator and the first layer is cross glass.

4 is also an insulator and is the second layer of cross glass.

4a is the surface of the cross glass which is the second layer of insulator, and is the surface on which the upper layer conductor 5 is formed.

In this case, the exposed portion 2a is connected to the lower layer conductor 2 as shown in FIG.
The first and second layer insulators 3.4 formed above are exposed by forming through holes with approximately the same diameter.

5 is an upper layer conductor.

Reference numeral 6 denotes an intermediate conductor, which is formed and added to the exposed portion 2a provided at a desired location of the lower layer conductor 2, and serves as a connection point with the upper layer conductor 5.

6a is the surface of the intermediate conductor 6.

Next, the operation of the multilayer printed wiring board according to the present invention having the above structure will be explained.

As shown in FIG. 2, the cross glass layer of the insulating layers 3 and 4 is not locally formed at the desired location of the lower conductor 2, and the exposed portion 2a is
The intermediate conductor 6 is previously formed and added to the exposed portion 2a, and then the upper layer conductor 5 is formed.

In the upper layer conductor 5 formed in this manner, the step distance Y between the cross glass surface 4a of the insulator 4, which is the printed surface of the upper layer conductor 5, and the surface 6a of the intermediate conductor 6 is small, so that the portion indicated by the arrow B in the figure is a predetermined film. Formed thickly.

Therefore, disconnection at the arrow B portion is prevented, and the lower layer conductor and the upper layer conductor are reliably connected.

The multilayer printed wiring board according to the present invention having the above-mentioned configuration and operation has the following effects.

(a) The connection between the lower layer conductor and the upper layer conductor becomes reliable, improving its reliability.

(b) Work process defects related to the connection between the lower layer conductor and the upper layer conductor are reduced, yield is improved, and manufacturing costs can be reduced.

(c) The connection component between the lower layer conductor and the upper layer conductor is simple and can be made compact with less space, so it has a wide range of applications.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a connection structure between a lower layer conductor and an upper layer conductor in a conventional multilayer printed wiring board. FIG. 2 is a vertical cross-sectional view showing the connection structure of the lower layer conductor and the upper layer conductor in the multilayer printed wiring board according to the present invention. 1...Insulating substrate, 2...Lower conductor, 3
, 4... Insulator, 5... Upper layer conductor, 6
・・・・・・Intermediate conductor.

Claims (1)

[Scope of utility model registration request] In a multilayer printed wiring board in which conductors and insulators are printed in multiple layers on the surface of an insulating substrate, the lower layer conductor and the first and second layer insulators formed on the lower layer conductor have approximately the same diameter. An exposed portion of the lower layer conductor that is exposed by forming a through hole, an intermediate conductor that is stacked on the exposed portion prior to forming the upper layer conductor, and the upper layer conductor that is electrically connected to the lower layer conductor via the intermediate conductor. A multilayer printed wiring board comprising: