Study of process dependent reliability in SiOC dielectric interconnects and film

Carbon doped oxides undergo surface carbon depletion induced by plasma etch and clean processes. The effect of this surface damage on dielectric reliability was assessed in patterned and blanket films using current-voltage (IV) methods. Among the process steps characterized, SiC etching imparted higher surface roughness and resulted in lower breakdown strength and higher leakage due to irreversible surface damage and carbon depletion of the SiOC dielectric. Moreover, it is postulated that fluoride ions from the etching plasma can penetrate the bulk SiOC dielectric, causing a significant increase in k-value.