METHODS FOR SELECTIVE ETCHING OF A MULTI-LAYER SUBSTRATE

摘要

A method is disclosed for the selective etching of a multi-layer metal oxide stack comprising a platinum or tungsten layer on a TiN layer on an HfO2 or ZrO2 layer on a silicon substrate. In some embodiments, the method comprises a physical sputter process to selectively etch the platinum layer, followed by a first wet etch using a mixture of NH4OH and H2O2 to selectively etch the TiN layer, and a second wet etch using a dilute mixture of HF and HCl to selectively etch the HfO2 or ZrO2 layer.