Methods for protecting a surface prior to etching to optimize etch performance

Abstract

The present disclosure provides various embodiments of methods for protecting an exposed metal surface of a metal layer prior to etching the metal layer using wet etch chemistry optimized for the bulk metal layer. In the embodiments disclosed herein, the exposed metal surface of the metal layer is protected by depositing a sacrificial metal layer on the exposed metal surface prior to etching the metal layer with the wet etch chemistry. The sacrificial metal layer protects the exposed metal surface by preventing oxidative passivation of the metal surface before and during etching the metal layer with the wet etch chemistry. In some embodiments, the techniques disclosed herein may be used to protect a surface of a ruthenium (Ru) layer prior to etching the ruthenium layer using halogenating etch chemistries in a wet atomic layer etching (ALE) process.