Low-Temperature Etching of Cu by Hydrogen-Based Plasmas

A simple, plasma-based, low-temperature etch process was developed for the subtractive etching of copper (Cu) films. Hydrogen (H 2 ) plasma etching of Cu thin films was performed in an inductively coupled plasma (ICP) reactor at temperatures below room temperature. This process achieved anisotropic Cu features and an etch rate of ∼13 nm/min. Cu etch rate and patterning results were consistent with an etch process that involved both chemical and physical characteristics. This conclusion was reached by consideration of the plasma as a source of ultraviolet photons, ions, and hydrogen atoms, which promote Cu etching.