Method of manufacturing a multi-layer ceramic substrate using a constraining green sheet

Abstract

Provided are a method of manufacturing a multi-layer ceramic substrate. The method includes preparing a non-sintered ceramic laminated structure formed of a plurality of ceramic green sheets; preparing one or more constraining green sheets comprising a first constraining layer formed of a first inorganic powder having a first particle diameter and a second constraining layer formed of a second inorganic powder having a second particle diameter larger than the first particle diameter; disposing the constraining green sheets on the top and the bottom of the ceramic laminated structure; and firing the ceramic laminated structure at a predetermined firing temperature.

1 . A method of manufacturing a multi-layer ceramic substrate, the method comprising:
 preparing a non-sintered ceramic laminated structure formed of a plurality of ceramic green sheets;   preparing one or more constraining green sheets comprising a first constraining layer formed of a first inorganic powder having a first particle diameter and a second constraining layer formed of a second inorganic powder having a second particle diameter larger than the first particle diameter;   disposing the constraining green sheets on the top and the bottom of the ceramic laminated structure; and   firing the ceramic laminated structure at a predetermined firing temperature.   
     
     
         2 . The method of  claim 1 , wherein the first inorganic powder of the first constraining layer has a first density, and the second inorganic powder of the second constraining layer has a second density lower than the first density. 
     
     
         3 . The method of  claim 2 , wherein the second constraining layer is equal to or lower than the first constraining layer in terms of the powder filling density. 
     
     
         4 . The method of  claim 2 , wherein the preparing of the constraining green sheets comprises:
 forming a slurry by adding an organic binder to a mixed powder of the first inorganic powder and the second inorganic powder; and   coating the slurry.   
     
     
         5 . The method of  claim 4 , wherein the coating of the slurry moves, by a density difference, the first inorganic powder with the first density downward to form the first constraining layer, and moves the second inorganic powder with the second density upward to form the second constraining layer. 
     
     
         6 . The method of  claim 2 , wherein the first density of the first inorganic powder is about 1.5 or more times higher than the second density of the second inorganic powder. 
     
     
         7 . The method of  claim 1 , wherein the second particle diameter of the second inorganic powder is about 2 or more times larger than the first particle diameter of the first inorganic powder. 
     
     
         8 . The method of  claim 1 , wherein the first inorganic powder is formed of at least one selected from the group consisting of cerium dioxide (CeO 2 ), zinc oxide (ZnO 2 ), and zirconia (ZrO 2 ). 
     
     
         9 . The method of  claim 1 , wherein the second inorganic powder is formed of at least one selected from the group consisting of alumina (Al 2 O 2 ), magnesia (MgO), and boron nitride (BN). 
     
     
         10 . The method of  claim 1 , further comprising:
 removing the constraining green sheets from the top and the bottom of the ceramic laminated structure after completion of the firing of the ceramic laminated structure; and   forming an external electrode on the ceramic laminated structure.