Patent ID: 7662477

Claim:
A multilayer ceramics substrate having a surface conductor on at least one surface of a multilayer body constituted by a plurality of laminated ceramics substrate layers, wherein a reaction phase formed by a reaction between a ceramics component in the ceramics substrate layers and a glass component in the surface conductor is deposited at an interface between the surface conductor and the ceramics substrate layers, wherein at least a ceramics substrate layer in contact with the surface conductor is formed from glass ceramics containing Al 2 O 3 as a filler component, while the surface conductor contains Zn as a glass component, wherein the multilayer ceramics substrate contains ZnAl 2 O 4 as the reaction phase, and wherein the ceramics substrate layer in contact with the surface conductor has an Al 2 O 3 content of at least 34 vol % but not greater than 40 vol % in at least a part in contact with the surface conductor.