Temperature Effects and Optical Emission Spectroscopy Studies of Hydrogen-Based Plasma Etching of Copper

Abstract

Optical emission spectroscopy (OES) and substrate temperature variation studies have been performed on Cu etch processes based on hydrogen (H2) plasmas. Temperature was varied between −150°C and 100°C. Gas phase Cu emission was detected during the H2 plasma etch processes. The correlation between Cu etch rate and Cu emission intensity trends as a function of temperature suggests that the Cu removal mechanism changes over the temperature range investigated. The hydrogen-Cu interaction chemistry plays a critical role in the etch process, suggesting that copper hydrides are likely etch products.