Monolithic ceramic substrate and method for making the same

Abstract

A monolithic ceramic substrate includes a green laminate having a plurality of green functional ceramic layers including a functional ceramic material, green support layers including a ceramic material that does not sinter at a sintering temperature for the green functional ceramic material to prevent shrinkage of the functional ceramic layers, first conductor patterns including a thin-film conductor, and second conductor patterns including a thick-film conductor. The green laminate is fired at the sintering temperature for the green functional ceramic material.

1 - 12 . (canceled)  
     
     
         13 . A method for making a monolithic ceramic substrate comprising the steps of: 
 preparing a green laminate including a plurality of green functional ceramic layers that include a functional ceramic material, at least one green support layer including a ceramic material that does not sinter at a sintering temperature for the green functional ceramic material, the at least one green support layer being in contact with at least one of the plurality of green functional ceramic layers to prevent shrinkage of the plurality of functional ceramic layers, a first conductor pattern including at least one thin-film conductor selected from the group consisting of a metal foil, a metal wire, and a conductive thin-film, the first conductor pattern being in contact with at least one of the plurality of green functional ceramic layers, and a second conductor pattern including a thick-film conductor in contact with at least one of the plurality of green functional ceramic layers; and    firing the green laminate at the sintering temperature for the green functional ceramic material.    
     
     
         14 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the green support layer is formed between two adjacent green functional ceramic layers.  
     
     
         15 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the first conductor pattern and the second conductor pattern are each formed between one of the plurality of green functional ceramic layers and the at least one support layer.  
     
     
         16 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the thin-film conductor of the first conductor pattern has a thickness of about 100 μm or less.  
     
     
         17 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the thin-film conductor of the first conductor pattern has a porosity of about 10% or less before sintering of the plurality of functional ceramic layers.  
     
     
         18 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the thin-film conductor of the first conductor pattern has a volume resistivity of about 2.5 Ω·cm or less and a surface roughness of about 5 μm or less.  
     
     
         19 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the area ratio of the thin-film conductor of the first conductor pattern to the plurality of functional ceramic layers is about 90% or less.  
     
     
         20 . The method for making a monolithic ceramic substrate according to  claim 13 , wherein the second conductor pattern is made of a conductive paste and has a thickness of about 30 μm or less after sintering of the plurality of functional ceramic layers.