Radical-based surface treatment and selective etch enabled by high density ICP remote plasma source

With Moore’s law continues to drive IC feature size and device density, advanced technology evolves to enable not only smaller feature size but also 3D structures for logic and memory chipmakers.1 The associated process requires precise surface/interface functionality and material loss control, as a result plasma damage free process and isotropic etch with high selectivity became crucial for advanced 3D transistor manufacturing. High density radical based processes provide ideal solutions with very low electron temperature, excellent step coverage and ultra-high selectivity. The highly reactive radicals can largely reduce thermal budget as well. In this article radical based surface treatments and material modifications including metal treatment, surface reduction and surface smoothing are discussed. Furthermore, the benefits of combining such surface treatment and radical based selective etch are also presented with examples of Si and TiN etch processes. Both surface treatment and selective etch processes are enabled by high density ICP plasmas generated radicals.