JPH0680892B2 - Manufacturing method of ceramic substrate - Google Patents

Description

Detailed Description [Overview] By stretching the film on both sides of the green sheet, the conductor paste can be filled from both sides of the green sheet, and the thickness of the green sheet penetrates. Even if the hole diameter is small and the aspect ratio is high, reliable quality can be obtained.

[Industrial application field]

The present invention relates to a method for manufacturing a ceramic substrate formed by firing a green sheet, and more particularly to a method for manufacturing a ceramic substrate that improves the filling of a conductive paste in a paste filling process to improve quality.

Ceramic substrates used in electronic devices are generally manufactured by stacking a plurality of green sheets on which pattern wiring and the like are formed and curing them by firing.

In recent years, such a ceramic substrate has been increasingly densified due to high-density mounting of mounted semiconductor elements and the like, and the width of the pattern wiring has been made as narrow as possible.

Therefore, the diameter of the via connecting the laminated pattern wirings is naturally small, and the quality of the via is deteriorated.

Therefore, it is desired to improve the quality of such a small diameter via.

[Conventional technology]

Conventionally, manufacturing was performed as shown in the conventional manufacturing process diagrams of FIGS. 3 (a) to 3 (f).

As shown in FIG. 3 (a), a soft green sheet material 11 is spread on the upper surface of the film 10 by a doctor blade 16 to have a predetermined thickness and dried to obtain a green sheet 1 by a doctor blade processing step. Is formed.

This green sheet 1 is cut into a predetermined size as shown in (b), and after cutting, as shown in (c), a film is formed.
A drilling process is performed to process the through hole 3 so as to penetrate 10 and the green sheet 1.

Next, as shown in (d), the conductive paste 4 is stacked on the upper surface of the film 10 so that the through holes 3 are filled with the conductive paste 4, and the squeegee 12 is operated as indicated by an arrow. As a result, a paste filling step of filling is performed.

As shown in (e), the film 10 is peeled off and the pattern 14 is formed by applying the conductive paste 4 by screen printing, as shown in (e). pattern as shown in f)
A firing process is performed in which a plurality of green sheets 1 on which 14 are formed are stacked and housed in a jig 15, pressurized by a cover plate 15A as shown by arrow A, inserted into a high temperature furnace, and fired.

In this case, the conductive paste 4 filled in the through holes 3 forms vias and is formed so as to connect the patterns stacked by the vias.

[Problems to be solved by the invention]

In such a manufacturing method, when the conductive paste 4 is filled, the diameter D of the through hole 3 with respect to the thickness T of the green sheet 1 is set.
Is extremely small, as shown in (d), the through hole 3
Cannot be completely filled with the conductive paste 4.

Therefore, when the green sheets 1 are laminated, there is a problem that the patterns 14 between the laminated layers are not connected in the worst case.

[Means for solving problems]

 FIG. 1 is a sectional view showing the principle of the present invention.

As shown in FIG. 1, the film (2) is stretched on both sides of the green sheet (1) after the doctor blade processing step,
In the paste filling step, the filling of the conductive paste (4) is performed from the two surfaces of the film (2) on which the conductive paste (4) is stretched.

By manufacturing in this way, the above-mentioned problems are solved.

[Operation] That is, the film is stretched on both sides of the green sheet so that the conductive paste can be filled from both sides.

Therefore, even if the diameter D is smaller than the thickness T, insufficient filling as in the conventional case can be avoided, and when the layers are stacked, the patterns are not disconnected and the quality can be improved. .

〔Example〕

The present invention will be described in detail below with reference to FIG. 2 (a) to (d) are manufacturing process diagrams of one embodiment according to the present invention. Throughout the drawings, the same reference numerals denote the same objects.

As shown in FIG. 2A, the film 2 is stretched on both sides of the green sheet 1 formed by the doctor blade processing step.

In this case, since the film 2 needs to be adhered to the dried green sheet 1, the film 2 may be thermocompression bonded, for example, if a film formed of polyvinylidene chloride material is used. good.

In the green sheet 1 having the film 2 stretched on both sides in this manner, the through holes 3 are punched by a punching process as shown in (b).

Next, as shown in (c), the conductive paste 4 is filled with A
From the side indicated by (4), the A side is set downward as shown in (d), and the conductive paste 4 is similarly filled from the B side.

Therefore, in the paste filling step, the conductive paste 4 is filled from both sides of the A and B sides.

Further, after the paste filling step, the film 2
Laminating and curing are performed by peeling, pattern formation, and firing process.

In this way, in the paste filling step, when the conductive paste 4 is applied from both sides of the film 2, the conductive paste 4 is filled into the through holes 3 from both sides.
On the other hand, even if the diameter D is small and the aspect ratio (T / D) is small, the through holes 3 can be sufficiently filled with the conductive paste 4.

〔The invention's effect〕

As described above, according to the present invention, the conductive paste can be sufficiently filled even in the through hole having a high aspect ratio.

Therefore, it is possible to improve the quality as compared with the related art, and it is possible to promote the high-density mounting by thinning the pattern, and the practical effect is great.

[Brief description of drawings]

FIG. 1 is a sectional view of the principle of the present invention, FIGS. 2A to 2D are manufacturing process diagrams of an embodiment according to the present invention, and FIGS. 3A to 3F are conventional manufacturing processes. The figure is shown. In the figure, 1 is a green sheet, 2 is a film, 3 is a through hole, and 4 is a conductor paste.

Claims (1)

[Claims] 1. A doctor blade forming step for forming a green sheet (1), a hole forming step for forming a through hole (3) at a predetermined position of the green sheet (1), and a conductor for the through hole (3). In a method for manufacturing a ceramic substrate formed by a paste filling step of filling a paste (4) and a firing step of hardening at a predetermined heating temperature, a film is formed on both surfaces of the green sheet (1) after the doctor blade processing step. (2) is stretched, and in the paste filling step, the conductive paste (4) is filled from two sides of the stretched film (2).