Specific Process Knowledge/Etch/DRIE-Pegasus
DRIE-Pegasus
The DRIE-Pegasus takes the well established Bosch process known from the ASE a significant step further. In the ASE the Bosch process has two cycles, etch and passivation. Within each cycle the process parameters are kept constant (This is, at least, that is the intention - the reality is that the ideal square function is rarely achieved during process parameter changes). In the passivation cycle, a C4F8 plasma is formed using the RF coil power only and a teflon-like coating is created on all surfaces thus protecting the sidewalls in the subsequent etch cycle. In the etch cycle the ion bombardment driven by the platen power first removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces) then as the bottom of the structures are opened the etch itself starts.
Details on DRIE-Pegasus
Further info: