Thin film capacitor having a metal foil with roughened main surfaces, manufacturing method therefor, and electronic circuit board having the thin film capacitor
AssigneeTDK Corporation
InventorsMiyu Hasegawa, Daiki Ishii
Life of this patent
Estimating the term…
Abstract
To provide a thin film capacitor having a large capacitance. A thin film capacitor includes a metal foil having roughened main surfaces, a dielectric film covering the main surfaces, an electrode layer contacting the metal foil through an opening formed in the dielectric film and having a surface formed as a metal terminal, an electrode layer contacting the dielectric film without contacting the metal foil and having a surface formed as a metal terminal, and an electrode layer contacting the dielectric film without contacting the metal foil. The electrode layers include a conductive polymer layer contacting the dielectric film.
Claims10
A thin film capacitor comprising:
- a metal foil having a first main surface and a second main surface opposite to the first main surface, both the first and second main surfaces being roughened;
- a first dielectric film covering the first main surface of the metal foil;
- a second dielectric film covering the second main surface of the metal foil;
- a first electrode layer contacting the metal foil through an opening formed in the first dielectric film and having a surface formed as a first metal terminal;
- a second electrode layer contacting the first dielectric film without contacting the metal foil and having a surface formed as a second metal terminal;
- and
- a third electrode layer contacting the second dielectric film without contacting the metal foil,
- wherein the second electrode layer includes a first conductive polymer layer contacting the first dielectric film,
- wherein the third electrode layer includes a second conductive polymer layer contacting the second dielectric film,
- wherein the metal foil has a through hole,
- wherein an inner wall of the through hole is covered with a third dielectric film, and
- wherein a third conductive polymer layer connecting the first and second conductive polymer layers is provided in a region surrounded by the inner wall of the through hole.
A method of manufacturing a thin film capacitor, the method comprising:
- roughening a first main surface of a metal foil and a second main surface opposite to the first main surface;
- forming first and second dielectric films respectively on the first and second main surfaces of the metal foil;
- exposing a part of the metal foil by removing a part of the first dielectric film;
- covering the first and second dielectric films respectively with first and second conductive polymer layers;
- forming a first electrode layer contacting the part of the metal foil and having a surface formed as a first metal terminal;
- forming a second metal terminal connected to the first conductive polymer layer;
- forming a through hole whose inner wall is covered with a third dielectric film in the metal foil before forming the first and second conductive polymer layers;
- and
- forming a third conductive polymer layer connecting the first and second conductive polymer layers in a region surrounded by the inner wall of the through hole.
Dependencies are inferred from the claim text.