A study of lead zirconate titanate etching characteristics using magnetized inductively coupled plasmas

In this study, Pb(Zr1−xTix)O3 (PZT) thin films were etched using magnetized inductively coupled plasmas (MICP) and their etch characteristics were compared with those by non-magnetized conventional inductively coupled plasmas (ICP). The use of Helmholtz type axial electromagnets around the chamber wall increased the PZT etch rates while decreasing etch uniformity. By using both the multidipole magnets and the axial electromagnets around the chamber wall, the etch uniformity could be improved while maintaining high PZT etch rates. PZT etch rates close to 1700 Å/min which are three times higher than those etched using the conventional ICP plasmas could be obtained with optimized MICP conditions. The etch selectivities over Pt at these conditions were higher than 1.5. The MICP used in the experiment showed higher Cl radicals and Cl2+/Cl+ ratios in the plasmas compared with those in the conventional ICP plasmas. Therefore, the increased chemical and/or physical sputtering by the increased Cl2+/Cl+ ratios along with the increased chemical reactivity by higher Cl radical densities appears to be responsible for high PZT film etch rates obtained with the MICP in our study. Using the MICP in 90%Cl2+10%Ar gas mixture, a nearly vertical etch profile could be also obtained.