Inverse microloading effect in reactive ion etching of silicon

摘要

We have investigated reactive ion etching of silicon and observed an inverse microloading effect, where the etch depth increases with the local pattern density. The increase is believed to be caused by an increased sputtering by silicon containing ions that become significant when there is a surplus of radicals in the plasma. We have also observed a conventional microloading effect by reducing the gas flow rate through the reactor, thus forcing the etch process into a regime where the supply of radicals is the limiting factor.