Pedestal lift for semiconductor processing chambers

A plasma processing chamber, comprising:

• a body comprising:
• a lid;
• one or more walls;
• and
• a bottom, wherein the lid, walls and bottom define an internal processing volume;
• a substrate support assembly disposed in the interior volume, the substrate support assembly comprising:
• a pedestal;
• and
• a shaft coupled to the pedestal, the shaft extending from the internal processing volume and through the bottom of the body;
• and
• a pedestal lift assembly coupled to the shaft and configured to move the pedestal vertically, the pedestal lift assembly comprising:
• a fixed frame;
• a platen configured to couple to the shaft of the pedestal, the fixed frame disposed between the platen and the pedestal;
• an absolute linear encoder disposed on the fixed frame and coupled via a rod to the platen, wherein the absolute linear encoder is configured to detect incremental movement of the platen;
• a lift rod coupled to the platen and extending through the fixed frame;
• and
• a movement assembly disposed on the fixed frame and moveably coupled to the lift rod, the movement assembly configured to move the lift rod in a first direction and a second direction, wherein the movement of the lift rod results in the displacement of the pedestal.

A method for processing a substrate in a plasma processing chamber, the method comprising:

• placing a substrate on a pedestal attached to a lift via a shaft coupled to a platen;
• moving the pedestal vertically upward by a moving assembly disposed on a fixed frame of the lift to a predefined up location, wherein the shaft extends through the fixed frame;
• determining a location of the pedestal using an absolute linear encoder disposed on the fixed frame and coupled via a rod to the platen;
• slowing the movement of the pedestal using the moving assembly upon the absolute linear encoder determining the location of the pedestal is approaching the predefined elevated location;
• and
• stopping the moving assembly to prevent further movement of the pedestal upon the absolute linear encoder determining the location of the pedestal is positioned at or near the predefined elevated location.