Abstract: Etching is selectively performed and selectively is modified using a treatment or pre-treatment with nitrogen radicals, prior to etching. Etching is performed with a gas phase chemistry etch. Different selectivities can also be provided in different processes or different regions (or different devices or different locations) of a substrate by the selective use and non-use of the treatment.

Abstract: An etch and surface modification is performed in a plasma, in which ions have been removed so that radicals of the plasma form a modified surface of a layer of substrate. A gas chemistry is reacted with the modified surface to form a reacted modified surface, and the reacted modified surface is removed.

Abstract: A method of processing a substrate that includes: forming an etch mask over a ruthenium (Ru) metal layer of a substrate, the etch mask exposing a first portion of the Ru metal layer and covering a second portion of the Ru metal layer; and converting the first portion of the Ru metal layer into a volatile Ru etch product in a processing chamber, the converting including exposing the Ru metal layer of the substrate to a halogen-containing vapor, and to a ligand-exchange agent to form the volatile Ru etch product, where the converting is an oxygen-free process.