A ceramic assembly is attached to a lower support structure having a bowl shape. The ceramic assembly has a top surface configured to support a substrate. At least one clamp electrode is positioned within an upper region of the ceramic assembly. A primary radiofrequency (RF) power delivery electrode is positioned within the ceramic assembly at a location vertically below the at least one clamp electrode such that a region of the ceramic assembly between the primary RF power delivery electrode and the at least one clamp electrode is substantially free of other electrically conductive material. A plurality of RF power delivery connection modules is distributed in a substantially uniform manner about a perimeter of the ceramic assembly. Each of the RF power delivery connection modules is configured to form an electrical connection from the lower support structure to the primary RF power delivery electrode at its respective location.