During plasma etching, the temperature of the silicon wafer being processed must remain constant.
Energetic ions strike the wafer during etching, transferring heat to the wafer. In the absence of cooling, the wafer temperature will rise. To remove heat from the wafer surface, the electrostatic chuck (ESC) holding the wafer must be cooled
Scaling of NAND devices beyond 48L layers requires more aggressive etch processing – with higher energy ions and longer etch times. The ESC must operate at lower temperatures, which requires sub-zero temperature seals that also resist the etch chemistries.
New FFKM material technology, such as Chemraz® 663, has been developed to ensure low temperatures during these process changes. Chemraz® 663 is the first FFKM that can operate at -40°C, and is compatible with etch processes.
Contact Greene Tweed for more information.