Multilayered capacitor and board having the same mounted thereon

Abstract

A multilayer capacitor includes a ceramic body including a dielectric layer, and having first to sixth surfaces, connected to the first surface to the fourth surface and opposing each other, a plurality of internal electrodes disposed inside the ceramic body, exposed to the fifth surface and the sixth surface, and having one ends exposed to the third surface or the fourth surface, and a first side margin portion and a second side margin portion disposed on end portions of the internal electrode, exposed to the fifth surface and the sixth surface, the first and second side margin portions are divided into an inner layer formed to be adjacent to the ceramic body, and an outer layer formed on the inner layer, and a dielectric constant of the inner layer is lower than a dielectric constant of the outer layer.

What is claimed is: 
     
         1 . A multilayer capacitor, comprising:
 a capacitor body including a dielectric layer, and having a first surface and a second surface, opposing each other, a third surface and a fourth surface, connecting the first surface to the second surface, and a fifth surface and a sixth surface, connected to the first, second, third and fourth surfaces and opposing each other;   a plurality of internal electrodes disposed inside the capacitor body, exposed to the fifth surface and the sixth surface, and having one ends exposed to the third surface or the fourth surface;   first and second external electrodes disposed on the third surface and the fourth surface of the capacitor body; and   a first side portion and a second side portion disposed on end portions of the internal electrode, exposed to the fifth surface and the sixth surface,   wherein the first and second side portions are divided into an inner layer formed to be adjacent to the capacitor body, and an outer layer formed on the inner layer, and a dielectric constant of the inner layer is lower than a dielectric constant of the outer layer.   
     
     
         2 . The multilayer capacitor of  claim 1 , wherein the first and second side portions are provided with a ratio of a dielectric constant of the inner layer to a dielectric constant of the outer layer equal to or less than 0.5. 
     
     
         3 . The multilayer capacitor of  claim 1 , wherein the first and second side portions are provided with a ratio of an average thickness of the inner layer to an average thickness of the outer layer of 0.08 to 0.15. 
     
     
         4 . The multilayer capacitor of  claim 1 , wherein an average thickness of the dielectric layer is equal to or less than 0.4 μm, and an average thickness of the internal electrode is equal to or less than 0.41 μm. 
     
     
         5 . The multilayer capacitor of  claim 1 , wherein an average thickness of the first and second side portions is equal to or less than 10 μm. 
     
     
         6 . The multilayer capacitor of  claim 1 , wherein a stacking number of the internal electrodes is 400 or more layers. 
     
     
         7 . The multilayer capacitor of  claim 1 , wherein each of upper and lower cover areas of the capacitor body is equal to or less than 20 μm. 
     
     
         8 . The multilayer capacitor of  claim 1 , wherein an average thickness of the first and second external electrodes is equal to or less than 10 μm. 
     
     
         9 . The multilayer capacitor of  claim 1 , wherein the first and second side portions are provided with an inner layer and an outer layer having thicknesses different from each other. 
     
     
         10 . The multilayer capacitor of  claim 1 , wherein each of the first and second external electrodes includes:
 first and second connecting portions disposed on the third surface and the fourth surface of the capacitor body, respectively, and connected to the internal electrode; and   first and second band portions extended onto portions of the first surface of the capacitor body from the first and second connecting portions.   
     
     
         11 . A mounting substrate of a multilayer capacitor, comprising:
 a substrate having first and second electrode pads on one surface; and   the multilayer capacitor according to  claim 1  mounted to allow first and second external electrodes to be connected to the first and second electrode pads, respectively.   
     
     
         12 . A multilayer capacitor, comprising:
 a body comprising first and second internal electrodes stacked in a thickness direction with a dielectric layer interposed between each pair of first and second internal electrodes, the first internal electrodes being exposed to a third surface of the body and spaced apart from a fourth surface of the body opposing the third surface in a length direction and the second internal electrodes being exposed to the fourth surface and spaced apart from the third surface;   a first external electrode disposed on the third surface and connected the first internal electrodes;   a second external electrode disposed on the fourth surface and connected to the second internal electrodes; and   first and second side portions disposed respectively on fifth and sixth surfaces of the body opposing each other in a width direction, each of the first and second side portions comprising inner layers contacting opposing edges of the first and second internal electrodes taken in the width direction, and outer layers disposed on corresponding inner layers and having thicknesses different from those of the inner layers.   
     
     
         13 . The multilayer capacitor of  claim 12 , wherein a ratio of a dielectric constant of the inner layer to a dielectric constant of the outer layer is in a range from 0.08 to 0.15. 
     
     
         14 . The multilayer capacitor of  claim 12 , further comprising an upper cover layer and a lower cover layer comprising a dielectric material, disposed respectively above and below the uppermost and lowermost of first and second internal electrodes. 
     
     
         15 . The multilayer capacitor of  claim 14 , wherein each of the upper and lower cover layers has a thickness less than or equal to 20 μm. 
     
     
         16 . The multilayer capacitor of  claim 12 , wherein each of the first and second internal electrodes has a thickness less than or equal to 0.41 μm. 
     
     
         17 . The multilayer capacitor of  claim 12 , wherein the dielectric layer has a thickness less than or equal to 0.4 μm. 
     
     
         18 . The multilayer capacitor of  claim 12 , wherein the outer layers of each of the first and second side portions have a dielectric constant greater than that of the inner layers.