Electricity: electrical systems and devices – Electrostatic capacitors – Fixed capacitor
Reexamination Certificate
1999-12-21
2001-04-03
Dinkins, Anthony (Department: 2831)
Electricity: electrical systems and devices
Electrostatic capacitors
Fixed capacitor
C361S305000, C361S306300, C361S311000, C361S313000
Reexamination Certificate
active
06212057
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flexible thin film capacitor using a high dielectric thin film, in particular, a flexible thin film capacitor used in flexible and compact portable electronic equipment such as an IC card as a flexible chip capacitor.
2. Description of the Prior Art
In recent years, compact and thin electronic equipment is in demand, and a circuit substrate used in the electronic equipment on which electronic components such as ICs and capacitors are mounted is required to be thin. Especially in a non-contact IC card, the thickness thereof is as thin as 1 mm or less, so that the thickness of the electronic component included therein is required to be several hundreds &mgr;m or less. For this reason, in order to obtain a capacitor having a large capacitance, a thin ceramic capacitor divided into several portions is proposed.
When a ceramic capacitor is used in the non-contact IC card, the capacitor cannot be as thin as the IC. In addition, in the case where the ceramic capacitor is mounted on a substrate, it becomes thicker by the contact layer. Furthermore, the mechanical strength becomes poorer as the ceramic capacitor becomes thinner, and therefore, when the ceramic capacitor is bent, it may be broken.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind, it is an object of the present invention to provide a high-quality and highly reliable flexible thin film capacitor that results in a thin mounted substrate on which the components are mounted, and is flexible so that it hardly is broken when being bent. Furthermore, it is another object of the present invention to provide a method for producing a flexible thin film capacitor having such excellent characteristics.
In order to achieve the objects, one embodiment of the present invention includes a substrate formed of at least one selected from the group consisting of an organic polymer and a metal foil, and an inorganic high dielectric film and metal electrode films formed on the substrate. The inorganic high dielectric film is interposed between the metal electrode films. The inorganic high dielectric film and at least one of the metal electrode films are formed in contact with an adhesive film on the substrate, thereby being integrated with the substrate by the adhesive film. It is preferable that the adhesive film is a metal oxide adhesive film.
Furthermore, one embodiment of a method for producing a flexible thin film capacitor of the present invention includes forming a first metal electrode film, an inorganic high dielectric film and a second metal electrode film in this order on a substrate formed of at least one selected from the group consisting of an organic polymer and a metal foil, using respective masks. The first metal electrode film and the inorganic high dielectric film are formed in contact with an adhesive film on the substrate, thereby being integrated with the substrate by the adhesive film.
The present invention allows the metal electrode films to adhere to the substrate firmly. In addition, for example, when a metal adhesive film is provided on a surface of an organic polymer, it is possible to form a high dielectric film having a high dielectric constant of &egr;
r
>10 without peeling from the substrate even at a low substrate temperature of about 300° C. Thus, the present invention can provide a high-quality and highly reliable flexible thin film capacitor in which no peeling nor damage occurs when it is bent.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.
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Kitagawa Masatoshi
Kohara Naoki
Sawada Taisuke
Dinkins Anthony
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P.C.
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