JPH08172029A - Thick film printed capacitor and its capacity adjusting method - Google Patents

Abstract

PURPOSE: To provide a thick film printed capacitor which is simple, reliable and with precision and its capacity being adjustable by improving the shape of an electrode constituting a capacitor. CONSTITUTION: By printing a conductor paste on a ceramics substrate 1, facing comb-like electrodes 2 are formed, and on the comb-like electrodes 2, a dielectric paste 3 is printed/applied so that a dielectric layer 3 is formed. The teeth part of the thick film print capacitor thus formed is selectively cut with laser light, etc., so that capacity is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode shape of a thick film printed capacitor and a capacitance adjusting method for the thick film printed capacitor.

[0002]

2. Description of the Related Art Conventionally, a thick film printed capacitor has been formed by sandwiching a dielectric layer between plane electrodes. Therefore, in the method of adjusting the capacitance of the thick film printed capacitor, the thick film printed capacitor is mounted on or in a ceramic substrate. By repeatedly firing a capacitor and heating it by irradiating it with laser light, the dielectric layer is deteriorated to adjust the capacitance.

[0003]

However, the above-mentioned conventional thick film printed capacitor has a multilayer structure of an electrode conductor paste, a dielectric paste, and an electrode conductor paste.
Short-circuiting between electrodes due to pinholes in the dielectric layer, disconnection of electrode conductors at the edges of the dielectric, and the like have occurred.
Further, there is a problem that the heat treatment at the time of adjusting the capacity deteriorates the characteristics of the dielectric and has a great influence on other parts.

The present invention is intended to solve the above-mentioned problems of the prior art. By improving the shape of the electrodes forming the capacitor, the present invention provides a thick film printed capacitor with high accuracy and high reliability, and at the same time, the capacitance is improved. It is an object of the present invention to provide a capacity adjusting method capable of easily and highly accurately adjusting.

[0005]

In order to achieve the above object, (1) a thick film printed capacitor of the present invention, an electrode conductor paste is printed in a comb shape facing each other on a ceramic substrate or a ceramic green sheet, A thick film printed capacitor is formed by printing and applying a dielectric paste on the electrodes.

(2) In the method of adjusting the capacitance of the thick film printed capacitor of the present invention, the capacitance is adjusted by selectively cutting the tooth portions of the opposing comb-shaped electrodes with laser light or the like. .

[0007]

According to the thick film printed capacitor of the above (1), since the electrodes sandwiching the dielectric can be formed at the same time, the number of printing steps for forming the electrode is reduced, and the short circuit between the electrodes due to the pinhole of the dielectric. Also, disconnection of the electrode conductor at the edge of the dielectric is eliminated.

Further, according to the capacitance adjusting method (2), the capacitance can be adjusted without directly applying a load to the dielectric forming the capacitor, and the capacitor incorporated in the ceramic substrate can also be used in the comb-shaped electrode. By similarly wiring the tooth portion of (1) to the outermost layer via the via conductor, the capacitance can be similarly adjusted.

[0009]

Embodiments will be described in detail below with reference to the drawings. FIG. 1 shows a thick film printed capacitor according to an embodiment of the present invention, in which 1 is a ceramic substrate, 2 is a comb-shaped electrode formed by printing and firing a conductor paste, and facing each other.
Reference numeral 3 denotes a dielectric layer printed and applied on the comb-shaped electrode 2, reference numeral 4 denotes a tooth portion of the electrode selectively cut by a laser beam or the like, and reference numeral 5 denotes a cut portion thereof.

The electrode conductor paste used is Ag / Pd (8
5/15) Organic powder was added to the powder, and the mixture was kneaded and prepared. The dielectric paste was Pb (Mg1 / 3, Nb2 / 3).
Those prepared by adding vehicle -PbO-PbTiO ₃ powder.

A comb-shaped electrode pattern is printed on the ceramic substrate 1 using a conductor paste, and the comb-shaped electrode pattern is printed in a box-type drying oven.
After drying at 150 ° C for 10 minutes and cooling, the dielectric paste is then applied by printing onto the comb-shaped electrodes, dried at 150 ° C for 10 minutes in a box-type drying oven, and then 900 ° C for 15 minutes in a belt-type firing oven. Was fired.

While the capacitance of the obtained thick film printed capacitor having the comb-shaped electrode 2 was measured with an LCR meter, the comb tooth portion was selectively cut (cutting point 5), and the cutting tooth portion 4 and the mating tooth portion 4 were mated with each other. The capacity of the portion sandwiched between the side teeth is reduced. In this way, by selectively cutting the comb teeth until the predetermined capacitance value is obtained, a thick film printed capacitor with high capacitance accuracy can be obtained.

[0013]

As described above, according to the present invention, the electrodes of the capacitor are formed in a comb shape so as to face each other to form the thick film printed capacitor, which can reduce the number of steps for forming the electrode, and the dielectric material. The short circuit between electrodes due to the pinhole and the disconnection of the electrode conductor at the edge portion of the dielectric are eliminated. As a result, the reliability of the thick film printed capacitor can be improved.

Further, according to the present invention, since the tooth portion of the comb-shaped electrode is selectively cut to adjust the capacitance, it is not necessary to directly apply a load to the dielectric material forming the capacitor or the entire substrate, and therefore the circuit board is provided. In, the capacitance of the thick film printed capacitor can be adjusted even after mounting other electronic components. Also, regarding the capacitor built in the ceramic substrate, the capacitance can be adjusted in the same manner by wiring the wiring of the comb-teeth portion to the outermost layer via the via conductor. In this way, it is possible to provide a thick film printed capacitor having high capacitance accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a thick film printed capacitor formed on a ceramic substrate according to an embodiment of the present invention.

[Explanation of Codes] 1 ... Ceramic substrate, 2 ... Comb-shaped electrode, 3 ... Dielectric layer, 4 ... Cut tooth portion, 5 ... Cut portion.

Claims (2)

[Claims] 1. A thick film printed capacitor, characterized in that the electrodes have a comb shape facing each other. 2. A method of adjusting the capacity of a thick film printed capacitor, which comprises selectively cutting the tooth portions of the comb-shaped electrodes facing each other to adjust the capacity.