ULTRAHIGH SELECTIVE NITRIDE ETCH TO FORM FINFET DEVICES

A substrate processing system for selectively etching a layer on a substrate includes an upper chamber region, an inductive coil arranged around the upper chamber region and a lower chamber region including a substrate support to support a substrate. A gas distribution device is arranged between the upper chamber region and the lower chamber region and includes a plate with a plurality of holes. A cooling plenum cools the gas distribution device and a purge gas plenum directs purge gas into the lower chamber. A surface to volume ratio of the holes is greater than or equal to 4. A controller selectively supplies an etch gas mixture to the upper chamber and a purge gas to the purge gas plenum and strikes plasma in the upper chamber to selectively etch a layer of the substrate relative to at least one other exposed layer of the substrate.