Substrate support assemblies and components

A substrate support assembly comprising:

• a platen characterized by a first surface configured to support a semiconductor substrate;
• a first stem section coupled with a second surface of the platen opposite the first surface of the platen, wherein a bottom end of the first stem section comprises a flange portion;
• a second stem section coupled with the first stem section, the second stem section comprising:
• a housing, wherein an upper end of the housing comprises a collar,
• a rod holder disposed within the housing,
• a connector seated within the rod holder at a first end of the connector,
• a heater rod disposed within the first end of the connector,
• a heater extension rod coupled with the connector at a second end of the connector,
• an RF rod,
• an RF extension rod extending through the rod holder, and an RF strap coupling an end of the RF extension rod with an end of the RF rod;
• and a sealing band that fits about a lateral surface of the flange portion and extends over a top surface of the flange portion and that couples with the collar of the housing to clamp the top surface of the flange portion to the housing along a longitudinal axis of the first stem section and the second stem section;
• wherein the RF rod is spatially separated from the RF extension rod near the flange portion.