JPH0377395A - Formation of conductor via - Google Patents

Abstract

PURPOSE:To enable the formation of a high-quality conductor via independently of the thickness of a ceramic wiring board by applying a conductor paste to the exposed plane of the ceramic wiring board and by making the inside of a sealed container into a pressure-reduced state in order to suck the conductor paste into a via forming hole. CONSTITUTION:A ceramic wiring board 1 on which a via forming hole 10 which penetrates the board from its upside to backside is contained in a sealed container 20, after which a conductor paste 15 is applied to the exposed plane, namely the upside, of said ceramic wiring board 1. The inside of the sealed container 20 is made into a pressure-reduced state in order to suck the conductor paste into the via forming hole 10 and to form a conductor via 5. thus, formation of the conductor via 5 can be done without strain and accordingly, a phenomenon where a part inside the via forming hole 10 which is not filled with the conductor paste 15 is formed can be eliminated properly.

Description

[Detailed Description of the Invention] [Summary] Regarding the method for forming conductive vias formed on the ceramic wiring board C2, a via formation method that allows formation of high-quality conductive vias regardless of the thickness of the ceramic wiring board C2 is provided. In order to provide a method, a ceramic wiring board having via formation holes penetrating from the front surface to the back surface is housed in an airtight container, a conductive paste is applied to the exposed surface of the ceramic wiring board, and then the airtight It is characterized by a configuration in which conductive vias are formed by reducing the pressure inside the container and sucking the conductive paste into the via forming holes.

[Industrial application field]

The present invention relates to a method for forming conductive vias in a ceramic wiring board.

[Conventional technology]

FIG. 3 is a side cross-sectional view of a main part showing a conventional conductor via forming method (hereinafter referred to as a via forming method) and an example of forming a conductor via; (b) shows the case where the plate thickness is thick, and (e) shows an example of forming the conductor iron.

As shown in Figure 3(a) and (b), this conductor via is
A ceramic wiring board 1 equipped with via forming holes 10 is mounted on a support stand 6.
0. (2) Apply a conductor base 1-15 over the ceramic wiring board 1. ■Move the squeegee 70 in one direction to apply this conductive paste 15 to the via forming hole 10.
Imprint it inside. ■Conductor base remaining on the surface) i,
After wiping off 5, it is placed in a firing furnace (not shown).
The conductive paste 15 is solidified by heating. It was formed in such a way. .

(Problems to be Solved by the Invention) In the conventional via forming method described above, when the thickness t of the ceramic wiring board 1 is small as shown in FIG. There is no problem because the forming holes 10 are filled without any force, but the ceramic wiring board WT becomes thicker (as shown in FIG. 3(t)).
T > t), the conductor base 5 cannot be sufficiently spread inside the via forming hole 10 with only the pressing force of the squeegee 70, and there is also no place for the air inside the via forming hole 10 to escape, so the via forming is difficult. An unfilled portion α of the conductive paste 15 is created in the hole 10. When firing with this unfilled portion α inside, this α is formed inside the conductor via 5 as shown in FIG. 3(C).
remains as a cavity, and the peripheral resistance increases, resulting in poor conduction of the conductor via 5.

The present invention has been made to solve these problems in conventional via forming methods.

[Means to solve the problem]

In the via forming method according to the present invention, conductive vias are formed using a via forming apparatus as shown in FIG. 1 and through forming steps as shown in FIG. That is, a ceramic wiring board 1 having via holes 10 extending through it from the front surface to the back surface is housed in an airtight container 20, and then a conductive paste 15 is applied to the exposed surface, that is, the upper surface, of the ceramic wiring board 1. death,
Next, the inside of the airtight container 20 is reduced in pressure, and the conductor paste 15 is sucked into the via formation hole 10 to form the conductor via 5.

[For production]

In the via forming method according to the present invention, the conductive paste 15 applied to the surface of the ceramic wiring board 1 housed in the airtight container 2o is sucked into the via forming hole lo by reducing the pressure inside the airtight container 20. Since the structure is such that the conductive via 5 is formed there, there is no difficulty in forming the conductive via 5, and therefore, the conductive paste 1 is formed in the via forming hole 10.
The phenomenon of formation of the unfilled portion α of 5 is precisely eliminated.

〔Example〕

Hereinafter, the present invention will be described in detail based on ten embodiment figures.

Figures 1 (al, b) and (c) are diagrams showing an example of the formation of conductor vias and the IJI power of the equipment used to form conductor vias, and (a) and crests) show the overall configuration of the equipment. A schematic side sectional view and a perspective view are shown, and (C) is a side sectional view of a main part showing an example of a conductive via formed using this method. However, in these figures, the same parts as in FIG. 3 are designated by the same reference numerals.

In the via forming method according to the present invention, conductive vias are formed using the via forming apparatus shown in FIGS. 1(a) and α)).

The configuration of this device will be explained below. This via forming device is
A vacuum pump is equipped with a pair of holding jigs 21 that hold the ceramic wiring board 1 in an airtight state, and an airtight container 20 that houses the holding jigs 21 in an airtight state, and also brings the inside of the airtight container 20 into a reduced pressure state. Equipped with 50. In the figure,
22 is a gasket that maintains airtightness between the ceramic wiring board 1 and the holding jig 21, and 23 is a gasket that maintains airtightness between the holding jig 21 and the airtight container 2.
This is a gasket that maintains airtightness between 0 and 0. Further, 40 is a valve installed between the airtight container 20 and the vacuum pump 50.

The holding jig 21 is an endless ring-shaped member having an L-shaped cross section, and the gaskets 22 and 23 are endless backing members made of, for example, bottom rubber, or O-rings. . Therefore, when housed in the airtight container 20, the ceramic wiring board 1 has air circulation between the inside and outside of the airtight container 20 only through the via forming holes 10.

FIG. 2 is a diagram illustrating the process of forming a conductor via according to the present invention.

The process of forming conductor vias will be described below with reference to FIGS. 1 and 2.

(1) A ceramic wiring board l having via holes 10 penetrating the front and back sides is housed in an airtight container 20 while being held between a pair of holding jigs 21. At this time, between the ceramic wiring board 1 and the holding jig 21, and between the holding jig 21 and the airtight container 2,
0, gaskets 22 and 23 are arranged as shown in FIG. 1(a).

(2) A conductor base opening 5 made by kneading copper powder and an organic binder is applied to the exposed surface of the ceramic wiring board 1 as shown in FIG. 1(a).

(2) Operate the vacuum pump 50 (or open the valve 40) to bring the inside of the airtight container 20 into a reduced pressure state. Airtight container 2
Ceramic wiring board 1
The conductive paste 15 applied thereon is sucked into the via forming hole 10 and filled therein. Note that at this time, since no air remains in the via forming hole 10, this filling is performed extremely smoothly.

(2) Stop the vacuum pump 50 (or close the valve 40) when the conductor paste 15 is completely filled into the via formation hole IO.

■Take out the ceramic wiring board 1 from the airtight container 20,
Wipe off the conductor base (15) adhering to both the front and back surfaces.

(2) Thereafter, this ceramic wiring board 1 is placed in a firing furnace to solidify the conductive paste 15.

FIG. 1(C) is a diagram showing an example of the formation of conductive vias 5 formed using the method of the present invention. As is clear from this figure, the conductor vias 5 formed by this method are of good quality with no unfilled portions α.This via formation method also improves the air circulation in the via formation holes 10. Therefore, no matter how thick the ceramic wiring board l is, no unfilled portion α of the conductive paste 15 will be formed in the via forming hole 10.

As described above, the via forming method according to the present invention is configured such that the conductive paste 15 is sucked into the via forming hole 10 in a very natural manner to form the conductive via 5.
Conductor vias can be obtained that are significantly more reliable than conventional via formation methods such as the squeegee method.

〔Effect of the invention〕

As is clear from the above explanation, the via forming method according to the present invention is configured such that the conductive paste is sucked into the via forming hole in a natural state, so that extremely high quality conductive vias can be formed. .

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1(a), (b), and (C) are schematic side cross-sectional views of main parts showing the configuration of a via forming apparatus used in the present invention and an example of forming conductive vias obtained thereby. Figure ε is a perspective view, Figure 2 is a process diagram showing the process of forming a conductor via according to the present invention, Figure 3 (a), (b) and (C1 shows a conventional via forming method and an example of forming a conductor via). This is a side sectional view of the main parts. In the figure, 1 is a ceramic wiring board, 5 is a conductor via, 10 is a via forming hole, 15 is a conductor paste, 20 is an airtight container, 21 is a holding jig, 22 and 23 are gaskets, 40 is the valve, 50 is the vacuum pump, α is the unfilled part, T and t are the thickness of the ceramic wiring board, respectively. (Q) (b) Mengzi Moryou's first form σJzner darkness part 5g ear 1;

Claims (1)

[Claims] Conductor via (5) formed in ceramic wiring board (1)
A method of forming a ceramic wiring board (1) in which a via forming hole (10) penetrating from the front surface to the back surface is formed is housed in an airtight container (20), and then the ceramic wiring board (1) is exposed. Apply a conductive paste (15) to the surface, and then apply the airtight container (20).
) by reducing the pressure inside the conductive paste (15) and sucking the conductive paste (15) into the via forming hole (10).
) A method for forming a conductive via, characterized by a configuration that forms a