In this study,we developed microfabrication process of lead-free sodium potassium niobate [(K,Na)NbO_3,KNN]thin films by dry etching.We deposited KNN thin films on Si substrate and evaluated its etching characteristics.We found that Ar/C_4F_8 plasma dry etching was effective for high etching rate 63 nm/min of KNN as well as excellent selectivity of KNN and Cr metal mask 5.7.We conducted fabrication of Pt/KNN/Pt unimorph microcantilevers through KNN etching process.We could fabricate micro-cantilevers without initial deflection and they show high piezoelectric coefficients d_31=110 pm/V.These results suggest that Ar/C_4F_8 plasma dry etching enable to apply for various lead-free piezoelectric MEMS fabrication processes.
