| 摘要 |
PROBLEM TO BE SOLVED: To suppress the firing shrinkage of a circuit board in the planar direction and, at the same time, to suppress the coefficient of firing shrinkage at the time of baking the board without relying upon press molding nor any unbaked ceramic board. SOLUTION: The circuit board is manufactured by baking a laminate prepared by laminating two kinds of unbaked ceramic insulating layers having different firing shrinkage starting temperatures upon another. At the time of manufacturing the circuit board, the firing shrinkage of the ceramic insulating layer having the lower firing shrinkage starting temperature is in progress to >=90% when the ceramic insulating layer having the higher firing shrinkage starting temperature starts to shrink. It is preferable to have a difference of >=10 deg.C between the firing shrinkage starting temperatures of the ceramic insulating layers and a difference of <=2×10<-6> / deg.C between the coefficients of thermal expansion of the insulating films after baking. |
