Thin film capacitor and method of manufacturing the same

Abstract

A thin film capacitor includes a metal foil, dielectric layers and internal electrode layers alternately disposed on the metal foil, and a top electrode layer on the topmost layer among the two or more dielectric layers. These layers have peripheries that define an outer profile flaring toward the metal foil as viewed from the stacking direction of the thin film capacitor, and at least one dielectric layer of two or more dielectric layers satisfies a relationship B>A>0 wherein A is a gap of the periphery of the internal electrode layer directly below the dielectric layer protruding from the periphery of the dielectric layer, and B is a gap of the periphery of the dielectric layer protruding from the periphery of the internal electrode layer or the top electrode layer directly above the dielectric layer. The thin film capacitor has a structure free from short-circuiting and reducing debris of broken dielectric material.

1 . A thin film capacitor, comprising:
 a metal foil;   two or more dielectric layers on the metal foil;   one or more internal electrode layers, each disposed between two adjacent dielectric layers, and   a top electrode layer provided on topmost layer among the two or more dielectric layers,   these layers having peripheries defining an outer profile flaring toward the metal foil as viewed from the stacking direction of the thin film capacitor, and   at least one dielectric layer of the two or more dielectric layers satisfying a relationship B>A>0 wherein A is a gap of the periphery of the internal electrode layer directly below the dielectric layer protruding from the periphery of the dielectric layer, and B is a gap of the periphery of the dielectric layer protruding from the periphery of the internal electrode layer or the top electrode layer directly above the dielectric layer.   
     
     
         2 . The thin film capacitor of  claim 1 , wherein
 the gap A is 2 μm or more.   
     
     
         3 . A method of manufacturing a thin film capacitor, comprising the steps of:
 (a) alternately depositing dielectric films and conductive films on a metal foil to fabricate a laminated body including two or more dielectric films each disposed between the metal foil and a conductive film farthest from the metal foil; and   (b) patterning the laminated body serially from a side of the dielectric film farthest from the metal foil such that these layers have peripheries defining an outer profile flaring toward the bottom of the laminated body as viewed from the stacking direction, and   in step (b), the dielectric films and the conductive films are processed such that at least one dielectric film of the two or more dielectric films satisfies a relationship B>A>0 wherein A is a gap of the periphery of the conductive film directly below the dielectric film protruding from the periphery of the dielectric film, and B is a gap of the periphery of the dielectric film protruding from the periphery of the conductive film directly above the dielectric film.   
     
     
         4 . The method of manufacturing the thin film capacitor of  claim 3 , wherein
 in step (b), the laminated body is patterned by wet etching.