Inductively coupled plasma etching of ultra-shallow Si3N4 nanostructures using SF6/C4F8 chemistry
Résumé
A reproducible inductively coupled plasma (ICP) etching process using simultaneously SF 6 /C 4 F 8 gases for the fabrication of ultra-shallow Si 3 N 4 nanostructures is presented. The effect of varying etching parameters such as the coil and platen RF power, the chamber pressure, the C 4 F 8 flow rate and the platen temperature on Si 3 N 4 and ZEP etch rates are investigated. The passivation and etching chemistry balance is used to slow down the Si 3 N 4 etch rate to a limit of 6 nm/min. For lower etch rates, the passivation regime is getting dominant and the surface roughness increases. 10 nm deep Si 3 N 4 nanostructures are patterned without inducing any additional roughness on etched surfaces.