JP2919953B2 - Method for manufacturing multilayer substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a method for manufacturing a multilayer substrate having through holes such as a multilayer microwave circuit.

(Prior Art) As a line for transmitting a microwave, a triplate line in which a center conductor is shielded by upper and lower ground conductors is known.

The multi-layer structure microwave circuit has such a tri-plate line in a multi-layer structure and is connected by through holes between the tri-plate lines.

In a multi-layer microwave circuit, various microwave circuits can be mounted on each layer, so that high-density mounting of the microwave circuit is easily realized.

FIG. 8 is a diagram showing the steps of a conventional manufacturing method for such a multilayer microwave circuit.

First, as shown in FIG. 8 (a), the one side than the center conductor 1 ₂ and the second layer unit substrate 2 ₂ conductors is removed, the other is the central conductor 1 ₄ formed on one surface adhering the first 3-4 layer portion substrate 2 ₃₄ to which the ground conductor 1 ₃ formed (except for the vicinity of the portion where the through hole is formed to be described later) faces the entire surface.

Next, as shown in FIG. 8 (b), the center conductor of the second layer is formed.
1 ₂ a through hole to take the continuity between the central conductor 1 ₄ of the fourth layer
To form a 3 _24, pass through holes 4 ₂₄ to a predetermined position.
Then, after treating the surface with a solvent so as to facilitate electroless plating glue to the inner surface of the hole 4 _24, pouring an electroless plating solution in the hole 4 _24, a thin plating layer on the inner surface of the hole 4 ₂₄ Let it form. Further, to form a thick plating layer 5 ₂₄ multiplied by electroplating inside a thin plating layer of the holes 4 _24.

Then, as shown in FIG. 8 (c), the second layer substrate ₂₂
When the upper and lower of the 3-4-layer substrate 2 _34, to bond the only ground conductor 1 _1, 1 first layer substrate 2 ₁ and the fifth layer portion substrate 2 _{5 5} is formed on one surface.

Further, as shown in FIG.
So as to surround the periphery of the _24, first layer substrate 2 ₁ of the ground conductor 1 ₁ and the ground conductor 1 ₅ and several through holes 3 a of the fifth layer portion substrate 2 _5
15 Connect by. These through holes 3 ₁₅ ,
... are formed in the same manner as the through hole 3 ₂₄ described above. These through holes 3 ₁₅ ,.
₂₄ can be regarded as a coaxial line.

The multilayer microwave circuit is manufactured by the above method.

By the way, recently, there is an extremely strong demand for mounting a microwave circuit at a higher density.

For this reason, it is possible to further improve the high-density mounting by making the multi-layer structure microwave circuit more multilayer than the above five layers and mounting various microwave circuits on each layer.

However, when the multi-layered microwave circuit has more layers than the above five layers, there is a problem that it cannot be manufactured by the above-described conventional manufacturing method.

This will be described with reference to FIG. This figure shows a case where the multilayer microwave circuit has seven layers.

As shown in the figure, other than the center conductor 6 ₂ the second layer substrate 7 ₂ are central conductor 6 ₄ formed on one side entire surface of another face to the ground conductor 7 ₃ are formed a conductor is removed and a second 3-4 layer portion substrate 7 ₃₄ adhered, through for taking conduction of the center conductor 6 ₄ of the second layer portion substrate 7 ₂ of the center conductor 6 ₂ and the 3-4-layer portion between the substrates 7 ₃₄ After the holes ₈₂₄ are formed, the third and fourth layer substrate 7
_{Fifth 34} center conductor 6 ₄ and are pierced 9 for the through hole to take the conduction of the center conductor 6 ₆ sixth layer portion substrate 7 ₆
Adhering a layer portion substrate 7 ₅ and the sixth layer portion substrate 7 _6.

Next, poured an electroless plating solution in the hole 9 of the through hole for making the center conductor 6 ₄ of the 3-4-layer portion substrate 7 ₃₄ conducting central conductor 6 ₆ sixth layer portion substrate 7 ₆ However, since both sides of the hole 9 are not open, the electroless plating solution cannot be poured. That is, in the conventional manufacturing method, it can not form a through hole for making the center conductor 6 ₄ of the 3-4-layer portion substrate 7 ₃₄ conducting central conductor 6 ₆ sixth layer portion substrate 7 _6.

(Problems to be Solved by the Invention) As described above, the conventional manufacturing method of the multilayer microwave circuit has a problem that it cannot be manufactured when the multilayer microwave circuit has more than five layers. .

The present invention has been made based on such circumstances,
It is an object of the present invention to provide a method of manufacturing a multilayer substrate having a multilayer structure and capable of manufacturing a multilayer substrate formed by connecting the respective layers by through holes.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to a method of manufacturing a multilayer board in which each layer is connected by a through hole, wherein a hole is formed at a position where the through hole is formed in each layer. A first step, a second step of applying an easily removable solvent to the inner surface of the hole that does not require plating, and a third step of applying an electroless plating solution to the inner surface of the hole And a fourth step of removing the electroless plating applied on the solvent from the inner surface of the hole together with the easily removed solvent, and the remaining electroless plating remaining on the inner surface of the hole. A fifth step of subjecting the surface to be subjected to electrolytic plating.

(Operation) In the present invention, even when the multilayer substrate is laminated into five or more layers, the hole of the through hole is not closed by the substrate when pouring the electroless plating solution. It is possible to manufacture a multilayer substrate formed by connecting the layers.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

Here, an embodiment in the case of manufacturing a seven-layer structure microwave circuit will be described.

1 (a) to 1 (g) are diagrams showing the configuration of each layer,
These are manufactured by etching a substrate.

As shown in FIG. 1 (a), a first layer portion 11 _1, the dielectric 1
The entire surface of one side of the 2 ₁ by forming a ground conductor 13 _1. The second layer portion 11 _2, as shown in Fig. 1 (b), by forming a center conductor 13 ₂ on a surface of the dielectric 12 _2. 3rd-4th layer part 1
1 _3, 11 _4, as shown in FIG. 1 (c), respectively dielectric
12 ₃₄ One of the entire surface to form the ground conductor 13 _third surface of, by forming a center conductor 13 ₄ on the other surface. Fifth layer portion 11 _5, first
As shown in FIG. (D), by forming a ground conductor 13 ₅ on the entire surface of one surface of the dielectric 12 _5. Sixth layer 11 _6, as shown in FIG. 1 (e), the central conductor 1 on one surface of the dielectric 12 ₆
3 ₆ was formed composed of. Seventh layer portion 11 _7, as shown in FIG. 1 (d), by forming a ground conductor 13 ₇ on the entire surface of one surface of the dielectric 12 _7. And these dielectrics 12 ₁ , 12 ₂ , 12 ₃₄ , 1
2 _5, 12 arranged _6, 12 _7, as shown in FIG. 1 (g).

Next, as shown in FIG. 2, the central conductor 1 on the dielectric 12 ₂
3 ₂ and the center conductor 13 ₄ on the dielectric 12 _34, for forming a through hole for connecting each of the central conductor 13 ₆ on the central conductor 13 ₄ and the dielectric 12 ₆ on the dielectric 12 _34, dielectric Body 12 ₁ , 12 ₂ ,
12 _34, 12 _5, 12 drilled 14 to _6, 12 ₇ predetermined position, and the surface treated by injecting resin for surface treatment agent on the inner surface of each hole 14, the electroless plating is easily glue.

Next, as shown in FIG. 3, holes that do not require plating
An etching resist film forming agent 15 is applied to the inner surface of the substrate.

Next, as shown in FIG. 4, the dielectrics 12 ₁ , 12 ₂ , 12 ₃₄ , 1
2 _5, 12 _6, 12 ₇ adhering the laminated.

Next, as shown in FIG. 5, an electroless plating solution is injected into the hole 14 to form electroless plating on the inner surface thereof. Since the electroless plating formed on the etching resist film forming agent 15 is hardly compatible with the etching resist film forming agent 15, the electroless plating is easily peeled off immediately.

Next, as shown in FIG. 6, the holes 14 are removed with an aqueous solution such as HC1 so as to separate the etching resist film forming agent 15 together with the electroless plating formed on the surface thereof.

Then, electrolytic plating is performed on the electroless plating to form a thick plating layer 16.

Each Thus the central conductor 13 ₄ on the central conductor 13 ₂ and the dielectric 12 ₃₄ on the dielectric 12 _2, on the dielectric 12 ₃₄ center conductor 13 ₄ and the dielectric 12 on the ₆ center conductor 13 ₆ and the through holes 17 _24, 17 ₄₆ to be connected are formed.

Next, as shown in FIG. 7, the through holes 17 ₂₄ , 17 ₄₆
Are connected by several through-holes 18 so as to surround each of the conductors 13 ₁ , 13 ₃ , 13 ₅ and 13 ₇ . These through-holes 18, ..., the through hole 17 _24, 17 ₄₆ is as regarded as coaxial line.

Therefore, according to the present embodiment, even when five or more layers are stacked in the multi-layered microwave circuit, the through hole is not closed by the substrate when the electroless plating solution is poured, so that the electroless plating solution is poured. Through holes can be formed.

Although the above-described embodiment has been described with reference to the case where the multilayer substrate is a microwave circuit having a multilayer structure, the present invention can be similarly applied to other multilayer circuit substrates.

[Effects of the Invention] According to the manufacturing method as described above, even if the multilayer substrate is laminated into five or more layers, the hole of the through hole is not closed by the substrate when pouring the electroless plating solution. Further, it is possible to manufacture a multilayer substrate in which the respective layers are connected by through holes. As a result, high-density mounting becomes possible by the manufacturing method of the present invention.

[Brief description of the drawings]

FIG. 1 is a top view and a cross-sectional view of each layer in the present invention, FIG. 2 is a cross-sectional view when a hole for a through hole is formed in each layer in the present invention, and FIG. Sectional view when an etching resist film agent is applied to holes for bonding, FIG. 4 is a sectional view when each layer in the present invention is bonded and laminated, and FIG. 5 is an electroless hole in a hole for a through hole in the present invention. FIG. 6 is a cross-sectional view when plating is formed, FIG. 6 is a cross-sectional view when the etching resist film forming agent is removed from a hole for a through-hole in the present invention, and FIG. 7 is a diagram for connecting the center conductor of each layer in the present invention. FIG. 8 is a cross-sectional view and a top view when a ground through-hole for forming conduction between several ground conductors is formed around the hole of the through-hole. FIG. Top view and cross section, Fig. 9 It is a cross-sectional view of a seven-layer structure microwave circuit according to the conventional manufacturing method. 11 ₁第 first layer portion, 11 ₂ … second layer portion, 11 ₃ ３third layer portion, 11 ₄ … 4th layer portion, 11 ₅ … 5th layer portion, 11 ₆ …. 6
Layer part, 11 ₇ …. Seventh layer part, 12 ₁ , 12 ₂ , 12 ₃₄ , 12 ₅ , 12 ₆ , 12 ₇ …
… Dielectric, 13 ₁ , 13 ₃ , 13 ₅ , 13 ₇ …… Ground conductor, 13 ₂ , 13 ₄ , 13 ₆
...... center conductor 14 ...... hole, 15 ...... etching resist film forming agent, 16 ...... plating layer, 17 _24, 17 _46, 18 ...... through hole.

Claims (1)

(57) [Claims] 1. A method of manufacturing a multilayer board comprising layers connected by through holes, a first step of forming holes in the respective layers at positions where the through holes are formed, and plating the inner surface of the holes by plating. A second step of applying an easily removable solvent to the inner surface of the hole that is not required; a third step of applying an electroless plating solution to the inner surface of the hole; and a step of applying the applied removal from the inner surface of the hole. A fourth step of removing the electroless plating applied on the solvent together with an easy solvent, and a fifth step of electroplating the remaining surface of the electroless plating among the inner surfaces of the holes. A method for manufacturing a multilayer substrate, comprising: