JPS6124296A - Thick film hybrid ic - 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 the Invention The present invention relates to a hybrid IC using a ceramic substrate forming through holes in the structure of a thick film hybrid IC.

Conventional configuration and its problemsThick film paste is printed in a desired pattern by screen printing, etc., and fired.In the case of Lufted IC, when both sides of the board are used, electrical continuity is established between the conductor layers on the upper and lower surfaces. Therefore, it is necessary to provide a conductor layer also in the through holes formed in the substrate. A common method for forming a through-hole conductor layer is to use vacuum suction and screen printing to suck up the conductor paste into the through-holes of the substrate.

However, in conventional ceramic substrates, the edges of the through-hole portions 2 of the ceramic substrate 1 are almost at right angles as shown in FIG. Due to the extremely thin thickness compared to the inner wall of the hole, there were major problems in terms of initial characteristics and reliability, such as high electrical resistance in the through-hole section and open circuits during high current loads. Conventional methods to solve these problems include printing the through-hole area multiple times after drying or baking, or printing the through-hole area with a special high viscosity. There are methods such as using conductor paste.

However, in the former case, these methods require very complicated steps.

In the latter case, there are management issues such as having to prepare a high viscosity paste in addition to the conductor paste for flat printing, and ensuring the conductor thickness at the through-hole edge. Therefore, there were many problems such as having to use an excessive amount of expensive conductive paste for other parts, which was a major practical drawback.

OBJECTS OF THE INVENTION The present invention relates to a hybrid IC that eliminates various drawbacks found in conventional ICs.

Structure of the Invention In the hybrid IC of the present invention, the through-hole edge portion is not at a right angle but is tapered or rounded.
When printing under vacuum suction, the conductor layer in the through-hole can be formed to have a uniform thickness at the same time as the conductor layer is printed on the plane of the substrate.

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

As shown in Figure 2, the through-hole portion 4 is polished by barrel polishing.
While vacuum suctioning an alumina substrate 6 whose edges have been rounded, a conductor paste 8 is printed onto the surface of the substrate and inside the through-holes using a screen plate 6 and an executor 7 in the same process to form a conductor layer 9. As a result, as shown in Fig. 3, the conductor layer 1o in the through-hole part can be formed with a uniform thickness on the substrate plane part, the through-hole inner wall part, and the through-hole edge part. The electrical resistance of the through-hole part is similar to the value of the flat part of the board, and furthermore, there is no occurrence of order of magnitude during high current loads, and very good results can be obtained in terms of initial characteristics and reliability. did it.

Furthermore, good results were also obtained when rounding the edges of through-holes using a sandblasting method in which hard, fine powder was sprayed at high speed.

Furthermore, in the manufacturing process of the alumina substrate, the green sheet 13 is formed using a mold die 12 that has a paris facing in the − direction as shown in FIG. 4 and has a large clearance with respect to the mold punch 11. When performing drilling, it was possible to form a good radius and taper at the edge of the through hole, similar to the above-mentioned barrel polishing and Sand Plus I processing on the sintered substrate.0 Effects of the Invention In the invention, the conductor layer in the through-hole portion can be easily formed to have a uniform thickness by a normal vacuum suction printing method,
All of the drawbacks seen in conventional through-hole structures are eliminated, and it is extremely advantageous in practice.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the state of a conductor layer in a conventional through-hole structure, FIG. 2 is a diagram showing a printing method on an alumina substrate having a through-hole structure according to an embodiment of the present invention, and FIG.
The figure is a cross-sectional view showing the state of the conductor layer in the same through-hole shape, and FIG. 4 is a cross-sectional view showing the state of forming the through-hole shape of the present invention. 1.4...Ceramic substrate, 11...
Mold punch, 2...Through hole part, 12...
... Mold die, 3.9 ... Conductor layer, 13
... Green sheet, 5 ... Alumina substrate, 6 ... Screen plate, 7 ... Squeegee, 8 ... Conductor paste, 10.・・・・・・
・Conductor layer of through-hole part. Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] Thick film hybrid I with a taper or radius formed at the edge of the through hole to electrically conduct the circuits on both sides of a ceramic substrate that forms thick film circuits on both sides.
C.