JPS61278193A - Manufacture of ceramic wiring 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 (Field of Industrial Application) The present invention relates to a method of manufacturing a ceramic wiring board suitable for use in ceramic packages for semiconductor devices and the like.

(Prior Art) A multilayer ceramic wiring board such as a ceramic package for a semiconductor device is manufactured by laminating a plurality of green sheets each having a wiring pattern formed on the surface and firing the green sheets. A conductive portion between each wiring pattern is formed by filling a conductive material into a via through hole provided through the green sheet.

FIG. 8 shows a conventional method of filling a via through hole with a conductive material, which will be described below.

First, make a via through hole 31 on the green sheet 30...
The through-holes 31 are filled with a binder, an organic solvent, and a paste 33 by screen printing on metal powder such as tungsten powder or molybdenum powder from the top of the mask 32 stacked on the top surface of the green sheet 30. Note that 34 is a squeegee.

(Problem to be solved by the invention) However, the conventional method described above has the following problems.

First, when filling the through holes 31 with the conductive paste 33 by screen printing, the green sheet 30 is
The conductive paste 33 oozes into the gap between the conductive paste 33 and the mask 32, and as a result, it adheres to the surface of the green sheet 30, which tends to cause a short-circuit accident in the wiring pattern.

Secondly, in the case of screen printing, since the conductive paste 33 is imprinted into the through holes 31 with the squeegee 34, air bubbles may be generated in the filled conductive paste 33a, and unfilled areas ( Holes, dents) are likely to occur, which may cause poor continuity. This is particularly likely to occur when the green sheet 31 is thick or when the conductive paste 33 has a high viscosity.

Thirdly, the life of the mask 32 is short, requiring frequent replacement, and the conductive paste 33 contains an organic solvent, which may worsen the working environment.

(Means for solving the problems) The present invention eliminates the various problems mentioned above. In particular, the via through holes passing through the green sheet are filled with a conductive material,
Ceramic material that allows conduction between both sides of the green sheet.
The method for manufacturing a 7-wire wiring board is characterized by the following: As shown in the drawings (particularly Figures 1 to 4 showing each process), after overlapping the green sheet 1 and the conductive sheet 2, the via through The conductive sheet 2 is punched out by a punching bunch 4a of a punching die 4 having a punching bunch 4a arranged at a position corresponding to the hole 3, and the conductive material 5 is filled into the via through hole 3.

(effect) Next, the operation of the present invention will be explained.

First, as shown in FIG. 3, the conductive sheet 2 is stacked on top of the green sheet 1 in which via through holes 3 have been formed in advance using the punching die 4 if necessary, and the punching bunch 4a placed in the punching die 4 is moved downward. If the via through hole 3 and each bunch 4a... Material 5)
directly connect via through hole 3 as shown in Figure 4.
It will be filled into.

(Example) Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

FIGS. 1 to 4 show each step of carrying out the method of the present invention.

FIG. 5 is a vertical cross-sectional view of the punching die, and a partial cross-sectional view of the manufactured ceramic wiring board.

First, the outline of the punching die 4 will be explained with reference to FIG.

The punching die 4 includes a lower die 11 at the lower part and an upper die 12 which moves up and down at the upper part. A die 13 having an opening corresponding to the position of the via through hole 3 is formed on the upper surface of the lower mold 11.

Further, the upper die 12 is provided with a plurality of punching bunches 4a corresponding to the positions of the die 13. The punching bunch 4
The magnitude of the movement stroke of a can be controlled arbitrarily.

Next, the manufacturing method according to the present invention will be sequentially explained.

As shown in FIG. 1, first, a green sheet 1, which is a workpiece, is sewn onto a lower mold 11.

After this, as shown in FIG. 2, the upper mold 12 is lowered,
The green sheet 1 is sandwiched between the lower mold 11 and the upper mold 12, and the punching bunch 4a is moved downward to remove the green sheet 1 one by one to form the via through hole 3. At this time, the downward stroke of the punching bunch 4a is the maximum (
bottom).

Next, as shown in FIG. 3, the conductive sheet 2 is placed on the green sheet 1 in which the via through holes 3 are formed. This conductive sheet 2 is made by mixing a binder such as methyl cellulose with conductive powder, which is a high-melting point metal such as tungsten powder or molybdenum powder, and adding necessary additives such as an organic solvent and a dispersant to the slurry, which is then prepared using a doctor blade. It is formed into a tape shape using methods such as methods. This conductive sheet 2 is molded to have appropriate hardness and brittleness so that it can be easily punched out, and its thickness is made approximately equal to the thickness of Green Sea 1-1.

Then, as shown in FIG. 4, the upper mold 12 is lowered,
The green sheet 1 and the conductive sheet 2 are sandwiched between the lower mold 11 and the upper mold 12, and the punching bunch 4a is moved downward to punch out the conductive sheet 2. At this time, the downward stroke of the punching bunch 4a is controlled to a moving distance from the upper surface 2a of the conductive sheet 2 to approximately the lower surface 2b, and the part of the conductive sheet 2 punched downward, that is, the conductive material 5, is just It fits within the via through hole 3 of the sheet 1.

By firing the green sheet 1 manufactured through the above steps, a ceramic wiring board is obtained. Furthermore, as shown in FIG. 5, by laminating and firing a green sheet 20 with a required wiring pattern (not shown) on its surface and a plurality of green sheets 21 formed in the same manner, ceramics for semiconductor devices can be produced. - Obtain a desired multilayer ceramic wiring board 22 such as a solid package.

In addition, the conductive sheet 2 can be formed into a long tape shape as described above, and can be automatically fed sequentially by a certain length each time a new green sheet 1 is filled with the conductive material 5. Further, the conductive sheet 2 after the conductive material 5 is punched out is recycled and used.

Next, a modified embodiment will be described with reference to FIGS. 6 and 7. FIGS. 6 and 7 are longitudinal cross-sectional views of the punching die 4 showing each modified embodiment.

In the modified embodiment shown in FIG. 6, the via through holes in the green sheet 1 are punched out at the same time as the conductive material 5 is punched out from the conductive sheet 2. In other words, in the embodiment shown in FIGS. 1 to 4, the conductive material 5 is first formed after the via through hole 3 is formed in the green sheet 1, but in the modified embodiment shown in FIG. The green sheet 1 with unprocessed through holes and the conductive sheet 2 are overlapped, and in this state, the punching bunch 4a is moved downward in the same manner as in the process shown in FIG. Punching and punching for forming via through holes 3 in the green sheet 1 using the punched conductive material 5 can be performed simultaneously. Such embodiments can be implemented as appropriate depending on the thickness and brittleness of each sheet 1, 2, for example.

Further, the modified embodiment shown in FIG. 7 can be used when the conductive sheet 2 is formed to be relatively hard compared to the green sheet 1, and in step G shown in FIG. When placing it on the green sheet 1, a thin rigid metal plate 25 having an opening 26 is interposed as shown in FIG. This effectively prevents stress deformation of the green sheet 1 when the conductive sheet 2 is punched out and the via through holes 3 are filled with the conductive material 5. In addition, the metal plate 25
The opening 26 for passing the conductive material 5 in the green sheet 1
When punching the via through hole 3, it can be punched at the same time. Further, the methods shown in FIG. 7 may be combined and implemented.

Although the embodiments have been described above, the present invention is not limited to such embodiments, and the details of the shapes.

Changes in configuration, quantity, arrangement, etc. can be made as desired without departing from the spirit of the present invention.

(Effects of the Invention) As described above, in the method for manufacturing a ceramic wiring board according to the present invention, the conductive sheet stacked on the green sheet is punched out using a punching die equipped with bunches, and the via through holes are filled with a conductive material. Obtaining great effects such as.

- Since a viscous paste-like conductive material is not used as in the past, there are no problems such as the conductive material oozing out and adhering to the green sheet surface, causing short-circuit defects in the wiring pattern. Therefore, the distance between the via through holes can be made denser, and the wiring board can be made smaller, more dense, and more reliable.

- No filling defects occur at all, and it is possible to always reliably fill a constant amount of conductive material, which is uniform in each via through-hole, resulting in a significant improvement in quality.

- Automation is extremely easy, and there is no need to replace screen printing masks as required in the past, streamlining work and improving the work environment.

[Brief explanation of drawings]

1 to 4 are vertical cross-sectional views of a punching die showing each step of carrying out the method of the present invention, FIG. 5 is a partial vertical cross-sectional view of a ceramic wiring board manufactured according to the present invention, and FIGS. 7
FIG. 8 is a vertical cross-sectional view of a punching die showing a modified embodiment of the method of the present invention, and FIG. 8 is an explanatory diagram showing a recent method for making a conductive material according to a conventional example. In addition, in the mother surface, 1... Green sheet, 2... Conductive sheet, 3... Via through hole. 4... Punching die, 4a... Punch. 5... Conductive material.

Claims (1)

[Claims] 1. A method for manufacturing a ceramic wiring board in which a conductive material is filled in a via through hole provided through a green sheet to establish electrical conduction between both surfaces of the green sheet. After the green sheets are stacked, the conductive sheet is punched out using a punch of a punching die provided with a punch placed at a position corresponding to the via through hole, and the conductive material is filled into the via through hole. A method of manufacturing a ceramic wiring board. 2. The method of manufacturing a ceramic wiring board according to claim 1, wherein via through holes are formed in the green sheet in advance using the punching die.