Capacitor

Abstract

A capacitor that includes an insulating substrate; a capacitance forming portion including a metal porous body, a dielectric film, and a conductive film; and a sealing portion that seals the capacitance forming portion. The capacitance forming portion is on a first main surface of the insulating substrate. A first external connection line including a first via conductor penetrating the insulating substrate from the first main surface side toward the second main surface side is connected to the metal porous body; and a second external connection line including a second via conductor penetrating the insulating substrate from the first main surface side toward the second main surface side is connected to the conductive film. When viewed in a normal direction of the first main surface, the first via conductor and the second via conductor are both in a region where the capacitance forming portion is disposed.

1 . A capacitor comprising:
 an insulating substrate having a first main surface and a second main surface opposed to the first main surface;   a capacitance forming portion on the first main surface, the capacitance forming portion including a conductive metal porous body, a dielectric film covering a surface of the metal porous body, and a conductive film covering the dielectric film;   a sealing portion on the first main surface and positioned so as to seal the capacitance forming portion together with the insulating substrate;   a first external connection line connected to the conductive metal porous body of the capacitance forming portion, the first external connection line including a first via conductor penetrating the insulating substrate so as to reach the second main surface from the first main surface; and   a second external connection line connected to the conductive film of the capacitance forming portion, the second external connection line including a second via conductor penetrating the insulating substrate so as to reach the second main surface from the first main surface,   wherein the first via conductor and the second via conductor are both located in a region where the capacitance forming portion is disposed when viewed in a normal direction of the first main surface.   
     
     
         2 . The capacitor according to  claim 1 , wherein the capacitor includes a plurality of the first via conductors and a plurality of the second via conductors. 
     
     
         3 . The capacitor according to  claim 2 , wherein
 the plurality of the first via conductors and the plurality of the second via conductors are arranged in an array when viewed in the normal direction of the first main surface, and   a polarity of adjacent via conductors at the shortest distance from each other among the plurality of the first via conductors and the plurality of the second via conductors are different from each other.   
     
     
         4 . The capacitor according to  claim 1 , wherein
 the first external connection line further includes a connection conductor on the first main surface that covers at least a part of the first via conductor, and   the metal porous body is bonded to the connection conductor, and the conductive film is bonded to the second via conductor.   
     
     
         5 . The capacitor according to  claim 4 , wherein the connection conductor is located only on the first via conductor. 
     
     
         6 . The capacitor according to  claim 4 , wherein the connection conductor is located on a portion of the first main surface excluding the second via conductor. 
     
     
         7 . The capacitor according to  claim 6 , wherein between the first via conductor and the second via conductor that are adjacent to each other at a shortest distance, the connection conductor extends to the second via conductor side from an intermediate position of a line connecting adjacent ends of the first via conductor and the second via conductor. 
     
     
         8 . The capacitor according to  claim 1 , wherein
 the first external connection line further includes an auxiliary connection conductor on the first main surface that does not cover the first via conductor and the second via conductor, and   the metal porous body is bonded to the auxiliary connection conductor.   
     
     
         9 . The capacitor according to  claim 1 , wherein, at a boundary portion between the second via conductor and the insulating substrate, the insulating substrate is covered with the dielectric film, the dielectric film is covered with the conductive film, and the conductive film is covered with the second via conductor. 
     
     
         10 . The capacitor according to  claim 9 , wherein the conductive film is a deposited film having a columnar structure including a columnar body grown in a direction substantially perpendicular to a surface of the dielectric film. 
     
     
         11 . The capacitor according to  claim 9 , further comprising a close contact layer between the conductive film and the second via conductor. 
     
     
         12 . The capacitor according to  claim 9 , wherein a surface roughness of the insulating substrate in a portion covered with the second via conductor is 200 nm to 20 μm. 
     
     
         13 . The capacitor according to  claim 9 , wherein
 the insulating substrate contains at least one of Al 2 O 3 , MgO, Mg 2 SiO 4 , BaTiO 3 , SrTiO 3 , and CaTiO 3  as a main material,   the dielectric film contains at least one of AlO x , SiO x , HfO x , and ZrO x ,   the conductive film contains at least one of TiN, WN, RuO 2 , ZnO, (Zn X Al 1-X ) O, and NiO, and   the second via conductor contains at least one of Cu, Ni, Ag, Sn, and Au.   
     
     
         14 . The capacitor according to  claim 1 , wherein the second via conductor has a tapered sectional shape decreasing from the first main surface side toward the second main surface side. 
     
     
         15 . The capacitor according to  claim 1 , wherein the metal porous body is a sintered body of metal grains. 
     
     
         16 . The capacitor according to  claim 1 , wherein a crystallite diameter of the metal porous body is 20 nm to 500 nm. 
     
     
         17 . The capacitor according to  claim 1 , wherein a part of the metal porous body enters the second via conductor in a portion penetrating the insulating substrate. 
     
     
         18 . The capacitor according to  claim 1 , wherein the metal porous body does not enter the second via conductor in a portion penetrating the insulating substrate. 
     
     
         19 . The capacitor according to  claim 1 , wherein the sealing portion comprises an insulating resin material or an insulating inorganic material. 
     
     
         20 . The capacitor according to  claim 1 , wherein
 the sealing portion includes an upper sealing portion opposing the insulating substrate when viewed from the capacitance forming portion, and a side sealing portion surrounding the capacitance forming portion between the insulating substrate and the upper sealing portion,   the upper sealing portion comprises an insulating resin material, and   the side sealing portion comprises a glass material.   
     
     
         21 . The capacitor according to  claim 1 , wherein
 a total number of via conductors including the first via conductor and the second via conductor is four or more, and   a diameter of the first via conductor and a diameter of the second via conductor are both 0.05 mm to 0.25 mm.   
     
     
         22 . The capacitor according to  claim 1 , wherein
 the first external connection line further includes a first bump portion covering the first via conductor at a position on the second main surface side, and   the second external connection line further includes a second bump portion covering the second via conductor at a position on the second main surface side.