Modeling of Advanced FinFET Dummy Gate Corner Residue Impacted By Clogging

In this work, we model 3D corner residues based on a process flow simulation using the Coventor SEMulator3D virtual platform. The role of clogging existing during plasma etch process in 3D corner formation has been studied based on the simulation results. In particular, the impacts of clogging and plasma aspect ratio distribution functions on corner size in typical etching steps are assessed. Furthermore, tunable model provides insights on the effect of fin height variation. Higher Fin structure could provide more shadowing effects which encourage the aggregation of 3D corner residue. In an advanced model containing multiple dry etch steps, the window of plasma divergence is also discussed, which is helpful to study and deal with the existing of 3D corner residue.