A number of different plasma chemistries have been investigated for the etching of oxides (indium tin oxide for conductive electrodes; alumina/titania and Al2O3 for insulators) and phosphors (SrS, ZnS) used in thin film electroluminescent displays. Under high ion density conditions, such as in an electron cyclotron resonance source, maximum etch rates above 1500 Angstrom/min are obtained for ZnS in Cl-2/Ar, BCl3/Ar, and SF6/Ar, for SrS in SF6/Ar and CH4/H-2/Ar, for ITO in CH4/H-2/Ar and for ATO in SF6/Ar. The etching is ion activated under most conditions, producing good feature anisotropy. Near-surface stoichiometry could generally be maintained on the etched surfaces of all materials except SrS where we invariably detected strong preferential loss of S. An optimized process for etching a typical metal-insulators-semiconductor-insulator-metal stack would involve switching plasma chemistries for each individual layer, but we have successfully patterned such a stack using only the CH4/H-2/Ar chemistry.