PLASMA ETCHING OF A SINGLE-CELL RF CAVITY -ASYMMETRIC ELECTRONEGATIVE DISCHARGE
We are pursuing the use of environmentally friendly dry etching of SRF cavity in Ar/Cl2 discharge. We have successfully demonstrated on flat samples that in a barrel-type reactor etching rates are comparable to the wet process, such as BCP or EP. The geometry of SRF cavities made of bulk Nb defines the use of asymmetric RF discharge configuration for plasma etching. The asymmetry in the surface area of a driven and grounded electrode creates a difference in the voltage drop over the plasma sheath attached to the driven electrode and the plasma sheath attached to the cavity surface. A specially designed single cell cavity is used to study these asymmetric discharges which contain 20 sample holder holes symmetrically placed over the cell. These sample holder holes can be used for both diagnostics and sample etching purposes. The approach is to combine radially and spectrally resolved profiles of optical intensity of the discharge with direct etched surface diagnostics to obtain an optimum combination of etching rates, roughness and homogeneity in a variety of discharge types, conditions and sequences.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1999204
- Report Number(s):
- JLAB-ACC-09-1094; DOE/OR/23177-1027
- Resource Relation:
- Conference: SRF2009, Berlin, Germany, September 20, 2009
- Country of Publication:
- United States
- Language:
- English
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