High heat loss heater and electrostatic chuck for semiconductor processing

Exemplary substrate support assemblies may include an electrostatic chuck body defining a support surface that defines a substrate seat. The substrate support surface may include a dielectric coating. The substrate support assemblies may include a support stem coupled with the electrostatic chuck body. The substrate support assemblies may include a cooling hub positioned below a base of the support stem and coupled with a cooling fluid source. The electrostatic chuck body may define at least one cooling channel that is in communication with a cooling fluid source. The substrate support assemblies may include a heater embedded within the electrostatic chuck body. The substrate support assemblies may include an AC power rod extending through the support stem and electrically coupled with the heater. The substrate support assemblies may include a plurality of voids formed within the electrostatic chuck body between the at least one cooling channel and the heater.