JPS5864097A - Method of producing multilayer printed circuit board - 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 The present invention relates to a method for manufacturing a multilayer printed circuit board, and the present invention relates to a method for manufacturing a multilayer printed circuit board with a streamlined process. Board (
Below, “Multilayer Pudding F.

``Board''. ), when electrically connecting between the internal conductor pattern layers and between the external and internal conductor pattern layers, install terminal 1 at the position where you want to connect the conductor pattern layers, as shown in the 1st WJ. Then, a hole 2 was made with a drill, and the inside of the hole 2 was plated and bonded. Also, as shown in the second [K], pre-drill the hole and insert it completely.
It is also practiced to laminate and bond the plates 3Yr which have been subjected to 11. However, all of the above-mentioned methods have a significant disadvantage in that they require a large number of man-hours to drill holes.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to completely eliminate the above-mentioned problems in the production of conventional multilayer principal plates 05, reduce the number of man-hours required for drilling, and reduce the number of holes. By making the diameter smaller.

multilayer printed circuit boards that enable increased wiring density.

The purpose is to provide a manufacturing method.

The above-mentioned object of the present invention is to provide a multilayer conductor having a plurality of inner conductor layers, a conductor pattern, and a hole for making an electrical connection between the eyebrows by laser processing.

In the method for manufacturing a layered printed board, when drilling holes by the laser processing, among the connection terminals of the conductor pattern layer to make the electrical connection, the connection terminal [excluding By providing a hole having a diameter slightly smaller than the beam diameter of the laser in the connection terminal of the metal conductor pattern layer where other electrical connections are to be made, the tree 1! The tube laser (I) is located at the deepest position when viewed from the laser irradiation side.

This is achieved by a method for manufacturing a multilayer printed board, which is characterized in that even the connecting terminals are removed.

The key point of the present invention is that there is a significant difference in the absorption of lasers, especially carbon dioxide lasers, between the resin and copper that make up the multilayer printed board, and copper has almost no absorption of carbon dioxide lasers.

The resin is selected by the laser, making full use of the irradiation.

Point k, where the hole for making the electrical connection can be opened in a short time by disassembling and removing the wire in a short time.

be.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 3(1) to 3(·) are diagrams showing a method of connecting an outer layer and an inner layer according to an embodiment of the present invention. First, Figure 3 (1)
As shown in K, the center position f6' of the terminal 6 provided on the outer steel foil layer
Next, a hole slightly smaller than the beam diameter of the carbon dioxide laser that will be used later for drilling is formed by etching. Next, as shown in FIG. 3(b), the surface of the substrate is scanned with a carbon dioxide laser LK of an intensity and irradiation time such that only the resin layer is removed, and the resin layer 8 is etched at the positions of the holes formed by the etching.
Remove it and make a hole. Below, as shown in Figure 3 (Q), BRAZ! After removing the resin layer in the holes provided in the resin layer 8 using a smear remover, the copper peat 1! (See the results in the third
Figure (d) shows K. ), etching (results are shown in Figure 3 (・
) to take revenge @) and create wiring pattern 9. Terminal 6 is formed.

In the third WJ (3rd WJ), since there is no hole in the inner layer terminal δ, the laser does not penetrate into the interior (below wi) K than the inner layer terminal 6, and it is possible to connect the outer layer and the desired inner layer. .

FIG. 4 shows another embodiment of the present invention, in which an outer layer and a plurality of inner layers 6, 7 are connected. In this case, it is necessary to form the small hole by etching at the center position of the terminal 6 provided on the outer layer and the center position of the terminal 7 provided on the inner layer, respectively. The above-mentioned connection can be made by cutting a hole in the inner layer to reach the terminal 6, and then plating the hole into the hole.

In the above embodiment, a soft acid gas is used as the laser.

Although a laser was used, the present invention should be limited to this.

It's not a thing.

Also, to conductors where electrical connections are to be made.

The holes to be provided also do not preclude opening 5 by a method other than etching.

As described above, according to the present invention, a plurality of inner layers.

A conductor pattern layer is formed, and a hole for making an electrical connection between the conductor pattern layers is made by laser processing.

In the production of a "multilayer printed board" as described above.

A hole is pre-drilled in the conductor at the location where electrical connection is to be made, and only the resin is removed by laser processing, allowing the characteristics of laser processing to be maximized and reducing the time required to drill the hole. The pore diameter can be reduced to 0.
Since the wiring density can be as small as 1 to 0.2, it is possible to provide a method for manufacturing a multilayer printed board that has excellent effects such as improved wiring density.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the connection of conventional conductor pattern layers, No. 31N C&) to (e) are cross-sectional views showing the method of connecting the outer layer and the inner layer, which is one embodiment of the present invention; +11A
FIG. 3 is a sectional view showing another embodiment of the present invention. 4: Outer layer steel foil, 5.6.7: Terminal, 8; Resin layer, 9!
Wiring pattern, L; laser. Patent applicant: Hitachi, Ltd., l]f, ,,,i Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] A method for manufacturing a multilayer printed circuit board having a plurality of inner conductor pattern layers, in which holes for making electrical connections between the conductor pattern layers are made by laser processing. When drilling holes by processing, among the connection terminals of the conductor pattern layer O to which electrical connections are to be made, other electrical connections are to be made except for the connection terminal which is the deepest +1 weight sum when viewed from the laser irradiation side. By providing a hole having a diameter slightly smaller than the zero beam diameter of the laser in the connection terminal of the layer, the resin existing at the position where the electrical connection is to be made is exposed to the laser when viewed from the laser irradiation side 5. A multilayer printed circuit board characterized in that even the deepest connection terminals are removed. Production method.