JPS59113613A - Method of forming end race electrode - 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 forming end face electrodes of composite circuit components that can be used in consumer electronic equipment circuits such as radio receivers, tape recorders, portable videos, etc.゛.

Conventional configurations and their problems In recent years, as the circuits of consumer electronic devices such as radio receivers, tape records, and portable videos have become increasingly miniaturized, inductors, which are difficult to incorporate into monolithic ICs,
The processing of passive elements such as high-precision resistors and large-capacity capacitors has become an obstacle to higher integration of analog circuits, and efficient implementation of these passive elements holds the key to ultra-miniaturization.

For this purpose, a multilayer ceramic capacitor, which is characterized by a large specific volumetric capacitance, is further combined with a multilayer composite capacitor as a Boehme substrate, and on this board, by trimming etc., high precision and stable characteristics can be obtained. Composite circuit components formed with thick film resistor circuits have been proposed. In this case, the extraction terminal of the multilayer composite capacitor is formed on the side surface, and in order to connect this terminal with the resistance circuit provided on the capacitor board, and to obtain continuity between the upper and lower surface circuits, , it is necessary to form a conductive layer on the edge surface as a lead-out terminal electrode for mounting on an external circuit. In addition, high stray capacitance occurs between the wiring that spans the top, bottom, and sides and the internal electrodes of the multilayer capacitor due to its high dielectric constant. It is also necessary to reduce this by providing .

Conventionally, screen printing has been commonly used as this type of method. First, on the laminated composite capacitor.

On the bottom and side surfaces, a low-permittivity dielectric layer is sequentially applied using unfired low-permittivity dielectric paste by screen printing using a silk screen or stainless steel screen, except for the capacitor terminals on the side of the board. Then, after heating and drying, it is fired. Next, conductive layers are similarly formed on the top, bottom, and side surfaces using unfired conductive paste, and the process is completed by heating and drying and firing.

However, this method attempts to connect layers on two mutually perpendicular surfaces only by dripping paste at the edge of the board by a combination of flat printing, and to obtain electrical continuity, which is not a normal connection. The required alignment margin is zero, it is fundamentally unreasonable, it is necessarily unreliable, and it is technically difficult and has poor productivity. Also,
This includes the possibility of short circuits due to bleeding due to imperfect perpendicularity at edges, and since alignment between the two layers of the conductor layer and dielectric layer is repeated many times, there is a risk of defects due to misalignment. There is also the issue of cumulative probabilities. Due to these difficulties associated with the formation of end face electrodes, the above-mentioned composite circuit component of a high-precision resistor-composite large-capacitance capacitor, although its effectiveness has been recognized, remains as a proposal at present.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems in forming end face electrodes of a resistor-capacitor composite circuit component and to provide a method for doing so simply and reliably.

Structure of the Invention The method for forming an end face electrode of the present invention involves forming a conductive layer in a desired shape on a base film that has been subjected to mold release treatment, and then depositing a low dielectric constant dielectric layer on top of the conductive layer so as to cover the conductive layer. form,
Furthermore, a thermoplastic resin layer is formed to cover the low-permittivity dielectric layer to prepare a multilayer film, and this multilayer film is laminated with a plurality of facing electrodes via a high-permittivity dielectric layer and drawn out on the side. The conductive layer is heat-pressed onto the side surface of a ceramic multilayer composite capacitor provided with electrodes so that at least a portion of the conductive layer protrudes on both surfaces, and after the base film is peeled off, it is fired. By making it possible to make circuit connections on the flat surface instead of the circuits that had to be made on the front surface, a sufficient alignment margin is secured, and by eliminating the multiple printing process on the side surface, workability is improved. This greatly improves reliability.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Figures 1 (a) and (b) are a plan view and a cross-sectional view taken along the plane X-X of the multilayer film used in the present β film. On the release-treated polyester base film 1, a conductive layer having a length exceeding the thickness of the substrate is formed as a first layer using an unfired conductive paste of 20% silver and 80% palladium by screen printing. Pattern 2 is formed, heated and dried.

This conductive layer will later become the terminal electrode of the resistor-capacitor composite circuit component, but from a circuit perspective, there are two types of conductive layers: one for simply providing continuity between the upper and lower circuits, and the other for the capacitor constructed within the board. In some cases, electrical conduction is obtained by connecting to the lead electrode 3 of a capacitor provided on the side surface. Next, as a second layer, a low-permittivity dielectric layer 4 is formed by applying glass paste so as to completely cover the conductive layer that has no connection to the side terminals of the composite capacitor, and is heated and dried.

This is to reduce the stray capacitance between the end face electrode and the electrode inside the substrate. At this time, a dielectric layer is not provided on the conductor layer that is connected to the side terminal of the composite capacitor for continuity, but the stray capacitance that increases at this time is added to the already large capacitance. It's not a problem.

Furthermore, as a third layer, a conductive layer 2.0 is formed using polyamide resin during heat compression bonding in a post-process. A thermoplastic resin layer 6 that contributes to adhesion of the low dielectric constant dielectric layer 4 to the substrate is formed by coating.

After drying, the multilayer film is completed. At this time, ethyl cellulose is mixed into the conductive paste and the dielectric paste to ensure flexibility after drying and adhesion between the layers.

As shown in FIG. 2, after predetermined alignment, the multilayer film is heat-pressed in a U-shape over the side, upper and lower surfaces of the composite capacitor substrate 6. At this time, the thermoplastic resin layer 5 is melted by heating and exhibits adhesiveness, and the base film 1 is easily peeled off due to its releasability, and the conductor layer and low-permittivity dielectric layer are attached to the edge of the composite capacitor. It is formed in a U-shape. By firing this in an 85C)C atmosphere, the formation of the end electrodes on the composite capacitor substrate is completed.

After applying a low-permittivity dielectric layer to the top and bottom surfaces using a standard thick film process, a resistor circuit is formed to obtain a reliable connection on the flat surface, eliminating the connection concerns at the edges of the conventional method. In addition, resistor and capacitor composite circuit components can be completed without any operational difficulties.

In this example, silver-platinum was used as the conductive material, but gold, silver, copper, or silver-platinum may also be used, and the third layer may also be made of other than polyamide, which melts during heat-pressing and becomes sticky. The organic substance mixed into the paste is not limited to ethyl cellulose as long as it can impart flexibility and adhesiveness. Also, the firing temperature was set to 8
Although the temperature was set at 50°C, this value may be selected as an appropriate value within the range of 500°C to 120°C depending on the paste and other components. The reason why the lower limit was set at 500°C is that if the temperature is lower than that, it will interfere with the melting of the glass components, so the upper limit is set at 1.
The reason why it is set to 20C) is that if it exceeds that value, the characteristics of the composite capacitor will deteriorate.

In addition, it is easy to infer by analogy that by constructing a multilayer film in which the developed pattern of the upper, lower, and side electrical circuits is formed using a thick film, it is possible to form the entire circuit or any part of it at once. can.

Effects of the Invention As is clear from the above explanation, the manufacturing method of the present invention uses a multilayer film to simultaneously form a low dielectric constant dielectric layer over the upper, lower, and side surfaces of the upper plate by heat and pressure bonding.
Eliminates the process of printing on the sides again in conventional methods,
It makes it possible to connect the upper and lower circuits with sufficient mating margin, overcomes the poor workability and poor yield associated with connections at the edges, and improves mass productivity and reliability in forming edge electrodes. This greatly improves the performance and contributes to the practical use of large-capacity, high-precision resistor composite circuit components.

This will pave the way to more efficient mounting of passive elements, which has been an obstacle to the miniaturization of consumer device circuits, and to realize this goal.

Furthermore, recently, attempts have been made to integrally sinter an inductor onto a composite capacitor substrate, and if this becomes practical, it will be possible to realize an LCR integrated module by using the method of the present invention, which will lead to ultra-miniaturization. It is expected that this will contribute to further progress in the field.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are a plan view and a cross-sectional view taken along line X-Xt of a multilayer film used in an embodiment of the present invention, and Figure 2 is a perspective view of the main parts of a composite circuit component on which end electrodes are formed. be. DESCRIPTION OF SYMBOLS 1...Base film, 2...Conductor layer, 3...Composite capacitor terminal electrode, 4...
. . . Low dielectric constant dielectric layer, 6 . . . Thermoplastic resin layer, 6 . . . Composite capacitor substrate.

Claims (3)

[Claims] (1) Form a conductive layer in a desired shape on a release-treated base film, form a low dielectric constant dielectric layer thereon so as to cover the conductive layer, and further form the low dielectric constant dielectric layer on the conductive layer so as to cover the conductive layer. A multilayer film is prepared by forming a thermoplastic resin layer so as to cover the layers, and this multilayer film is then laminated with multiple facing electrodes via a high-permittivity dielectric layer, and an extraction electrode is provided on the side. 1. A method for forming an end face electrode, which comprises heat-pressing the conductor layer to a side surface of a capacitor so that at least a part of the conductor layer projects on both sides, peeling off the base film, and then firing the conductor layer. (2) The method for forming an end electrode according to claim (1), using one selected from gold, silver, copper, silver-palladium, and silver-platinum as the material of the conductor layer. (3) A method for forming an end electrode according to claim (1) or claim (2), wherein the firing temperature is 600°C to 1200'C.