Selective Etching of HfO_2 by Using Inductively-Coupled Ar/C_4F_8Plasmas andthe Removal of Etch Residue on Si by Using an O_2Plasma Treatment

摘要

HfO_2 thin films were etched using an Ar/C_4F_8inductively-coupled plasma (ICP) for high etchselectivity of HfO_2/Si and the fluorocarbon remaining on silicon surface after the HfO_2etchingwas removed by using an oxygen ICP and its effect was investigated. The etching of HfO_2usingAr/C_4F_8magnetically-enhanced ICP (MEICP) improved the etch selectivity of HfO_2/Si by morethan three times, possibly due to the differences in the thicknesses of the fluorocarbon polymerlayers formed on the surfaces of HfO_2and Si. In addition, the oxygen ICP treatment after theHfO_2 thin film etching by using Ar/C_4F_8ICP removed the polymer layer on silicon surfaceeffectively, so for the HfO_2-nMOSFET (n-type metal-oxied-semiconductor-field-effect-transistors)devices, an improvement in drain current of more than 60 % could be observed after the O_2ICPtreatment.