JPH07221452A - Ceramic multilayer substrate - Google Patents

Abstract

PURPOSE:To make a substrate surface flat after baking and to enable large capacity. CONSTITUTION:A capacitor layer 2 and a capacitor electrode 3 are formed by printing and drying electrode paste and capacitor paste alternately in a specified part of a surface of an insulation layer green sheet 1. An insulation layer 4 is formed of insulation paste with the same composition as a ceramic element in the green sheet in a surface of the green sheet 1 in a periphery of a capacitor layer to be as thick as the capacitor layer 2. A ceramic green sheet is further laminated in an upper part and a multilayer substrate with a built-in capacitor is acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic multi-layer substrate having a built-in capacitor, and more particularly to a capacitor having a built-in capacitor layer which has no irregularities on the surface of the substrate and enables high capacity. .

[0002]

2. Description of the Related Art Conventionally, a ceramic multilayer substrate having a built-in capacitor is formed by sandwiching a plurality of capacitor layer green sheets 2 with a plurality of insulating layer green sheets 1 as shown in FIG. There is something. Further, as shown in FIG. 4, a capacitor electrode 3 and a capacitor layer 2 are formed on a predetermined portion of the insulating layer green sheet 1 by screen printing, and the insulating layer green sheet 1 is laminated and fired on the electrode 3. There are also things.

[0003]

However, the above-mentioned FIG.
In the structure shown in Fig. 1, a large-capacity built-in capacitor can be realized without the unevenness of the substrate surface, but the dielectric constant of the capacitor layer 2 is very high, so that an electrical cross between the via conductors 5 formed in the capacitor layer 2 Talk was a big problem.

Further, in the structure shown in FIG. 4, since the via conductor 5 is formed on the insulating layer green sheet 1, there is no problem of electrical crosstalk, but the insulating layer is formed on the partially formed capacitor layer 2. Since the green sheets 1 are piled up, unevenness is formed on the substrate surface, and there is a problem that the number of capacitor layers cannot be increased to achieve high capacity.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a ceramic multi-layer substrate having a flat surface and a large-capacity capacitor, which is free from crosstalk between via conductors. .

[0006]

In order to solve the above-mentioned problems, the ceramic multilayer substrate of the present invention is designed such that the capacitor electrode paste and the capacitor paste are alternately printed and dried on a predetermined portion of the surface of the green sheet for the insulating layer. A capacitor layer is repeatedly formed, and an insulating paste having a dielectric constant lower than that of the capacitor paste is printed on the surface of the green sheet on which the capacitor layer is formed so as to have the same thickness as the capacitor layer to form an insulating layer. However, a green sheet for an insulating layer is laminated on the capacitor layer and the insulating layer.

[0007]

According to the above construction, the capacitor layer is partially formed on the insulating layer and is not affected by electrical crosstalk. Further, since the insulating paste is printed so as to have almost the same thickness as the capacitor layer, the substrate surface after firing can be made flat, and the number of capacitor layers can be increased to achieve a large capacity.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a capacitor electrode paste containing Ag / Pd as a main component is printed and dried on a predetermined portion of an insulating layer green sheet 1 whose ceramic component is a mixture of lead borosilicate glass and alumina. Then, a capacitor layer paste containing a lead perovskite compound as a main component is printed and dried. This process is repeated, and the capacitor electrode paste is further printed and dried to provide the capacitor layer 2 including the capacitor electrode 3.
Is composed of two layers.

On the surface of the green sheet 1 on which the capacitor layer 2 is partially formed, an insulating layer paste having the same composition as the ceramic component in the green sheet 1 is printed to have the same thickness as the capacitor layer 2 for insulation. Form layer 4. The via conductor 5 of the insulating layer 4 can be formed by screen printing.

As shown in FIG. 2, the capacitor layer 2
And on the insulating layer green sheet 1 on which the insulating layer 4 is formed,
Further, another green sheet for insulating layers 1 was laminated by thermocompression bonding, and then the organic components were sufficiently removed in air at 450 ° C.
Firing was performed in air at 00 ° C. to obtain a ceramic multilayer substrate on which built-in capacitors were formed.

[0011]

As described above, in the ceramic multilayer substrate of the present invention, the periphery of the partially formed capacitor layer is printed with an insulating paste so that the unevenness of the capacitor layer is eliminated and the substrate surface is made flat. As a result, it is possible to achieve the same level of flatness as the surface of a board that does not have a built-in capacitor. Further, even if the thickness of the capacitor layer is increased by making the capacitor layer multi-layered, the flatness of the substrate surface is not lost, and the capacity can be increased.

Further, since the ceramic multilayer substrate of the present invention is formed by printing the insulating paste around the capacitor layer, the capacitor layer and the insulating layer adhere well and no gap is formed after firing. The performance and reliability of the substrate are also good.

[Brief description of drawings]

FIG. 1 is a sectional view of a ceramic multilayer substrate in one manufacturing process according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same ceramic multilayer substrate.

FIG. 3 is a sectional view of a conventional ceramic multilayer substrate with a built-in capacitor.

FIG. 4 is a sectional view of a conventional ceramic multilayer substrate with a built-in capacitor.

[Explanation of reference symbols] 1 green sheet for insulating layer 2 capacitor layer 3 electrode for capacitor 4 insulating layer 5 via conductor

Claims (1)

[Claims] 1. A green sheet on which a capacitor layer is formed by alternately printing an electrode paste for a capacitor and a capacitor paste on a predetermined portion of the surface of a green sheet for an insulating layer and repeating drying to form the capacitor layer. An insulating layer having a dielectric constant lower than that of the capacitor paste is printed on the surface so as to have the same thickness as the capacitor layer to form an insulating layer, and a green sheet for the insulating layer is formed on the capacitor layer and the insulating layer. A ceramic multi-layer substrate characterized by being laminated.