Etch Stop Device for Triode Plasma Etching
Original Publication Date: 1978-Jan-01
Included in the Prior Art Database: 2005-Feb-20
In a triode plasma batch etching system, positioning a "hat-shaped" element over a silicon wafer prevents etching of the SiO(2) layer. These elements are useful to prevent etching during the initial "pre-cleaning" transition period when the composition of the plasma is approaching its equilibrium composition and when the etch rate and etch rate ratio of the plasma varies with time. Furthermore, in the plasma etching of a batch of wafers, individual hat-shaped elements may be positioned directly over the individual wafers that have thinner SiO(2) layers when no more etching is wanted on those wafers while continuing to etch the other wafers that have thicker SiO(2) layers.