Importance

Loading Importance Indicators...

Abstract

A method of processing a workpiece in a plasma reactor having an electrostatic chuck for supporting the workpiece within a reactor chamber, the method including circulating a coolant through a refrigeration loop that includes inner and outer zone evaporators inside respective inner and outer zones of the electrostatic chuck, while pressurizing inner and outer zones of a workpiece-to-chuck interface with a thermally conductive gas, and sensing conditions in the chamber including inner and outer zone temperatures near the workpiece. The method further includes obtaining the next scheduled change in RF heat load on the workpiece and using thermal modeling to estimate respective changes in thermal conditions of the coolant in the inner and outer zone evaporators, respectively, that would hold temperatures measured in the inner and outer electrostatic chuck zones, respectively, nearly constant by compensating for the next scheduled change in RF heat load, and making the respective changes in thermal conditions of the coolant in inner and outer zone evaporators prior to the time of the next scheduled change by a head start related to the thermal propagation delay through the electrostatic chuck.

Loading the Abstract Image...

First Claim