Summary
Successful use of iodofluorocarbons (IFCs) in a high aspect ratio via etch has been demonstrated in a high density plasma etch tool.
Presently, 70-80% emissions reductions are possible, relative to C3F8 reference process
Process criteria for etch rate and feature profile have been met; bulk photoresist selectivity needs further development work.
Understanding of key differences between IFC plasmas and conventional perfluoroalkane plasmas has been critical to successful implementation of IFCs as etch chemistries.
In general, chemistries which are likely to offer substantial reductions in emissions are those resulting in significantly different plasma environments; developing an understanding of these environments can be nontrivial but is essential to the implementation of new chemistries as PFC replacements.