Electrostatic Wafer Holder for Wafer Cooling During Reactive Ion Etching
Original Publication Date: 1988-Jun-01
Included in the Prior Art Database: 2005-Feb-15
This wafer-holding technique for reactive ion etching (RIE) provides efficient cooling by electrostatic clamping of a wafer to an electrode surface. It makes use of the self-induced DC voltages, on the wafer for clamping and helium gas is applied to the back side of the wafer for conductive gas cooling at the same time. No external voltage supply is needed. (Image Omitted) Fig. 1 is a side sectional view of a holder using this technique. Fig. 2 is a top view of the holder of Fig. 1. As a result of electron and ion bombardment by the plasma on the wafer, electric charge is accumulated in the wafer, since it is unable to flow to the electrode through an insulator film (about 20 microns of a dielectric polymer) that is on the surface of the holder.