A two-level prediction model for deep reactive ion etch (DRIE)

We contribute a quantitative and systematic model to capture etch non-uniformity in deep reactive ion etch of MEMS devices. Non-uniformity depends on uneven distributions of ion and neutral species at the wafer-level, and local consumption at the die-level. An ion-neutral synergism model is constructed from data obtained from several layouts of differing layout pattern densities, and is used to predict wafer-level variation with an r.m.s. error below 3%. This model is combined with the die-level model, which we have reported previously [1], on a MEMS layout. The two-level model is shown to enable prediction of both within-die and wafer-scale etch rate variation for arbitrary wafer loadings.