Abstract: A joined structure includes: a ceramic member having a wafer placement surface; an embedded electrode that is embedded in the ceramic member and has a shape extending along the wafer placement surface; a metallic connection member embedded in a surface of the ceramic member that is opposite to the wafer-placement surface so as to reach the embedded electrode; and a metallic external energizing member joined to a surface of the connection member that is exposed to the outside with a joint layer interposed therebetween. The connection member has an arithmetic mean surface roughness Ra of 6 to 16 ?m.

Abstract: A wafer placement table includes a conductor unit. In the wafer placement table, a sub-RF electrode (first conductive layer) and a jumper layer (second conductive layer) are embedded at different levels in a ceramic substrate having a wafer placement surface, and the conductor unit establishes electrical continuity between the sub-RF electrode and the jumper layer. The conductor unit is a transversely placed coil or a transversely placed perforated cylindrical body.