1. Field of the Invention
The present invention relates to a ceramic chip-type electronic component such as a multilayer ceramic capacitor or a chip resistor, and to a method of making such an electronic component.
2. Description of the Related Art
Conventionally, a multilayer ceramic capacitor generally includes a chip body and a plurality of external electrodes. The chip body is formed by sintering a plurality of ceramic green sheets laminated one upon another. An internal electrode is provided on an obverse surface of each of the ceramic green sheets. The external electrodes are formed by sputtering of metal such as copper or by the application of metal paste such as copper paste, for example. Each of the internal electrodes is electrically connected to one of the external electrodes.
The multilayer ceramic capacitor having the above-described structure has a drawback that the chip body easily cracks or chips. For instance, when the multilayer ceramic capacitor is soldered on e.g. a printed circuit board, such cracking or chipping may occur due to the shock from the outside or the thermal expansion difference between the multilayer ceramic capacitor and the printed circuit board.
To prevent such cracking or chipping, JP-A-2004-296936 proposes to cover each of the external electrodes by a conductive elastic resin film containing metal powder. The elasticity of the conductive elastic resin film functions to absorb the shock from the outside to the chip body or the thermal expansion difference. Further, to facilitate the soldering, a metal plating film is formed on the conductive elastic resin film.
According to the above-described patent document, the conductive elastic resin film is formed by applying elastic resin paste mixed with metal powder by e.g. screen printing and then drying or hardening the paste applied. With such a technique, however, the metal powder existing at a surface of the conductive elastic resin film is covered by a thin film of elastic resin and is not exposed.
Since the metal powder is not exposed, the adhesion between the metal plating film and the conductive elastic resin film may be poor. Therefore, the metal plating film may be separated due to the shock from the outside or the thermal expansion difference between the multilayer ceramic capacitor and the printed circuit board. Moreover, since the metal powder is not exposed, any measures may need to be taken to enhance the adhesion between the metal plating film and the conductive elastic resin film, which leads to an increase in the manufacturing cost.
USPTO Backgrounds
USPTO Backgrounds