Green chemistry for SiN etch

Over the past few years, numerous countries and semiconductor manufacturing entities have unveiled their commitments to achieving net-zero carbon emissions by 2050 or even sooner. When it comes to manufacturing chips, plasma etch processes contribute significantly to emissions, especially in dielectric etching. These processes typically involve the use of high global warming potential (GWP) fluorocarbon gasses like CHF₃, CF₄, and CH₂F₂. Air Liquide's research and development (R&D) endeavors have led to the creation of multiple alternative etch chemistries for SiN and SiO₂ etching applications that boast remarkably low GWPs. Despite strides in developing these alternative chemistries, accurately forecasting the gases emitted post-plasma remains elusive. The complexities inherent in the breakdown and recombination processes within the plasma make it challenging to predict the specific emissions, regardless of whether the gas introduced into the plasma etch chamber carries a high or low GWP. This research showcases the utilization of Fourier Transform Infrared Spectroscopy (FTIR) to analyze and measure the emission gas stream from the plasma etch chamber. Moreover, the innovative chemistries developed by Air Liquide have exhibited enhanced etch performance while resulting in lower CO₂ equivalent emissions compared to the current baseline in dielectric etching.