Method of reducing wet etch rate of silicon nitride

摘要

A method of reducing the wet etch rate of silicon nitride relative to that of silicon oxide is disclosed. The method comprises implanting nitrogen-containing ions into silicon nitride films, followed by thermal annealing to repair the implant damage and concurrently promote Si-N bonding in the nitrogen-implanted films. The silicon nitride films thus treated are more resistant to oxide etchants such as HF. The present invention is particularly useful in reducing the wet etch rate of the silicon nitride formed by reacting hexachlorodisilane (Si2Cl6) with ammonia (NH3) at below 650° C.