Radical etching of metals for three-dimensional device fabrication with microwave ECR plasma system

The study highlights the effectiveness of using Hitachi High-Tech RAXIO for isotropic etching of metal films, crucial for the advancement of three-dimensional semiconductor devices. The RAXIO system, utilizing microwave electron cyclotron resonance for plasma generation, enables low-pressure radical etching, enhancing isotropy and selectivity while maintaining process reproducibility. This method proved superior to ion-assisted etching, particularly for tungsten and hafnium oxide, and also improved surface roughness for ruthenium and titanium nitride. The ability to clean accumulated by-products in the chamber further contributes to the consistency of the etching process.