Specific Process Knowledge/Etch/DRIE-Pegasus: Difference between revisions

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 #a higher pressure during the etch increases the density of reactive species and hence the etch rate. Since a high platen power is no longer necessary to drive the ion bombardement, lowering it will reduce the impact on the masking material thus improving the selectivity.
+[[Image:boostdelay4b.jpg |400x400px|thumb|The etch cycle is split into three parts: Boost, Delay and Main]]
 These conflicting demands are the same on the ASE. However, with hardware improvements on the DRIE-Pegasus such as
 *fast response digtal MFC's mounted on top of the process chamber itself to shorten the gas line
 *fast APC valve
 *fast RF power supply
-the etch and deposition cycles may be split into three separate phases, called Delay, Boost and Main.
+the etch and deposition cycles may be split into three separate phases, called Delay, Boost and Main. Following the arguments from above, the third phase (Delay) may be thought of as a short delay that ensures a very low pressure (and thus extremely good ion directionality) before the ion bombardment.
-[[Image:boostdelay4b.jpg |400x400px|thumb|The etch cycle is split into three parts: Boost, Delay and Main]]
-Following the arguments from above, the third phase (Delay) may be thought of as a short delay that ensures a very low pressure (and thus extremely good ion directionality) before the ion bombardment.
 ===[[Advanced_Silicon_Etcher_-_Pegasus|Details on DRIE-Pegasus]]===