Etch Process Trends. Etch process trends. Most trends are not consistent. They depend on the specific values of input parameters. At point A, pressure increases causes etch rate increase but at pint B, the trend is the inverse. Etch rate. B. Pressure. A. Gas flow rate.
Gas flow rate
Answer: higher pressure means more molecules to collide into for the ions in their trajectory (i.e. smaller Mean Free Path). Thus the their trajectory will be more scattered and thus less vertical less anisotropy.
Less like this
More like this
of input gases by plasma
ElectrodeThe effect of increased RF on Protective Film Generation
1) Reactants enter chamber
of reactants by electric fields
3) Reactant transport from bulk of plasma to surface of wafer
SubstrateEffect on Reactant delivery and by product removal process
Effect on Ion-bombardmentProcess
* Ion bombardment removes protective film on horizontal surfaces, exposing them to etching gas. It does not touch protective film on vertical surfaces, hence no vertical etch rate.
Region that feels the edge effect