MULTILAYER SUBSTRATE AND ITS PRODUCTION PROCESS

PROBLEM TO BE SOLVED: To provide a multilayer substrate in which the occurrence of swelling of a conductor layer is suppressed when it receives thermal hysteresis at high temperature in reflow process, while applying a dielectric material containing aromatic liquid crystal polyester and dielectric ceramic particles as an insulation layer. SOLUTION: The multilayer substrate comprises a plurality of insulation layers 5, an inner conductor layer 3 provided between adjoining insulation layers 5, and an outer conductor layer 7 provided on the outermost layer. The insulation layer 5 contains aromatic liquid crystal polyester and dielectric ceramic particles, the inner conductor layer 3 and the outer conductor layer 7 contain at least one of Cu and Ag, and protective layers 31, 32 and 33 containing a metal element having standard free energy of formation of an oxide lower than that of Cu are provided to cover the opposite sides of the inner conductor layer 3 and the insulation layer 5 side of the outer conductor layer 7, respectively. COPYRIGHT: (C)2008,JPO&INPIT