Código SA para mordazas para sierras

World Customs Organization Harmonized System Committee Classification Rulings Session 30

HS Code :	8466.20

Reference No :

Electrostatic chuck (ESC) consisting of an aluminium pedestal with a thin copper film between layers of polyimide. The polyimide coating protects the copper from the plasma and from arcing. The pedestal bolts to the surface of the simplified cathode. The ESC pedestal is either notched or flatted, depending on the type of wafer being used.
Helium channels cut into the top and bottom of the ESC distribute helium across the back of the wafer. The helium flow increases heat transfer from the wafer to the ESC pedestal. This helps prevent photoresist reticulation on the wafer. The helium is routed up through the cathode to the back of the wafer.
When a plasma ignites the chamber, it creates a charge at the backside of the wafer. A positive DC voltage is then applied to the copper film of the ESC. This results in a charge opposite in polarity to the charge at the backside of the wafer. The opposite charges attract, forming an electrostatic bond between the wafer and the ESC. This "chucks" the wafer, keeping the wafer in place when the backside helium pressure is enabled. After processing, the backside helium pressure is reduced and the voltage is lowered, allowing the plasma to dissipate the excess static charge. This "dechucks" the wafer. After dechucking, the wafer is ready to be transferred out of the chamber.

Source : World Customs Organization Harmonized System Committee Classification Rulings Session 30