Insulating Substrate and Manufacturing Method Therefor, and Multilayer Wiring Board and Manufacturing Method Therefor

Abstract

There is provided a dimensionally accurate insulating substrate in which plane direction-wise shrinkage is practically zero and shrinkage variations are small. The insulating substrate includes a laminated body composed of at least two kinds of insulating layers made of crystallizable glass ceramics. The crystallization temperature of crystallizable glass contained in the first insulating layer is lower than the softening point of crystallizable glass contained in the second insulating layer. The difference in thermal expansion coefficient between the first and second insulating layers is preferably 2×10 −6 /° C. or below.

1 - 7 . (canceled) 
     
     
         8 . A method for manufacturing an insulating substrate, comprising the steps of:
 preparing a laminated body composed of first and second insulating sheets containing crystallizable glass powder and ceramic powder, wherein a crystallization temperature of the crystallizable glass powder contained in the first insulating sheet is lower than a softening point of the crystallizable glass powder contained in the second insulating sheet; and   carrying out co-firing of the laminated body to fabricate an insulating substrate.   
     
     
         9 . The method of  claim 8 , wherein the first and second insulating sheets each have a crystallizable glass powder content of 30% by mass or above. 
     
     
         10 . The method of  claim 8 , wherein the crystallizable glass contained in the first and second insulating sheets forms at least one selected from the group consisting of diopside, hardestnite, celsian, cordierite, anorthite, gahnite, willemite, spinel, mullite, forsterite, and suanite. 
     
     
         11 . The method of  claim 8 , wherein the crystallizable glass powder contained in the first insulating sheet comprises: 5 to 20% by mass of SiO 2 ; 40 to 50% by mass of MgO; 10 to 30% by mass of B 2 O 3 ; and 0 to 30% by mass of at least one selected from the group consisting of CaO, Al 2 O 3 , SrO, ZnO, TiO 2 , Na 2 O, BaO, SnO 2 , P 2 O 5 , ZrO 2 , and Li 2 O, whereas the crystallizable glass powder contained in the second insulating sheet comprises: 30 to 50% by mass of SiO 2 ; 10 to 25% by mass of MgO; and 25 to 55% by mass of at least one selected from the group consisting of B 2 O 3 , CaO, Al 2 O 3 , SrO, ZnO, TiO 2 , Na 2 O, SnO 2 , P 2 O 5 , ZrO 2 , and Li 2 O. 
     
     
         12 . A method for manufacturing a multilayer wiring board comprising the steps of:
 preparing a plurality of the first and second insulating sheets of  claim 8 ;   applying a conductor paste in a wiring pattern at least to surfaces of partial insulating sheets among a plurality of the insulating sheets to form a conductor layer, the conductor layer predominantly containing at least one selected from the group consisting of Au, Ag, Cu, Pd, and Pt;   fabricating a laminated body by stacking a plurality of the insulating sheets; and   sintering the laminated body.   
     
     
         13 . The method of  claim 12 , wherein the conductor paste is prepared by blending an organic binder and a solvent into metal powder having a tap bulk density of 15% or above based on a density (d 20 ) of a metal element. 
     
     
         14 . The method of  claim 12 , wherein the second insulating sheet has a firing shrinking starting temperature T 2  which is higher than both a shrinking ending temperature T 3  of the first insulating sheet and a shrinking ending temperature T 4  of the conductor layer. 
     
     
         15 . The method of  claim 14 , wherein B 1 /B 2  is 0.90 or above, in which B 1  represents a volume content of the inorganic compound composed of the crystallizable glass powder and the ceramic powder contained in the first insulating sheet, and B 2  represents a volume content of the inorganic compound composed of the crystallizable glass powder and the ceramic powder contained in the second insulating sheet. 
     
     
         16 . The method of  claim 15 , wherein B 3 /B 2  is 0.90 or above, in which B 3  represents a volume content of the metal compound contained in the conductor layer.