Abstract: A method for oxygen depleted plasma etching and mixed mode plasma etching are disclosed. The method includes using an oxygen free etch plasma or a substantially oxygen free etch plasma at a high temperature to etch a stack including a plurality of layers of thin film materials. The oxygen depleted etching prevents or substantially reduces by-product re-deposition of titanium oxides generated by etching of titanium thin films in the stack. The titanium oxides can serve as a secondary mask layer that can cause defects in devices formed from the stack. Mixed mode plasma etching can include etching the stack with an oxygen free plasma, a substantially oxygen free plasma, and an oxygen containing plasma at different stages of a process.