Origin, evolution, and control of sidewall line edge roughness transfer during plasma etching

摘要

(cont.) micromasking. Porous films seem especially prone, perhaps due to polymer diffusion into the pore structure. Control of polymerization during the etch through the use of lower-polymerizing fluorocarbons or the addition of oxygen was shown to effectively control excessive roughening on solid films, while porous dielectrics remain challenging. Finally, an inductively-coupled plasma beam source was used to conduct a preliminary investigation into roughening of polysilicon in an HBr plasma beam. The initial polysilicon topography was shown to seed striation formation at glancing ion incident angles due to scattering and ion shadowing. These results indicate that, in a pure etching process (no deposition) the surface topography can be an important source of roughness and striation formation on sidewalls.