Exemplary semiconductor substrate supports may include a pedestal shaft. The semiconductor substrate supports may include a platen. The platen may define a fluid channel across a first surface of the platen. The semiconductor substrate supports may include a platen insulator positioned between the platen and the pedestal shaft. The semiconductor substrate supports may include a conductive puck coupled with the first surface of the platen and configured to contact a substrate supported on the semiconductor substrate support. The semiconductor substrate supports may include a conductive shield extending along a backside of the platen insulator and coupled between a portion of the platen insulator and the pedestal shaft.