Methods for Recess Etching

摘要

Methods for recess etching are provided herein that advantageously improve lateral to vertical etch ratio requirements, thereby enabling deeper recess etching while maintaining relatively shallow vertical etch depths. Such enhanced lateral etch methods advantageously provide benefits for numerous applications where lateral to vertical etch depth ratios are constrained or where recesses or cavities are desired to be formed. In some embodiments, a method of recess etching includes providing a substrate having a structure formed thereon; forming a recess in the substrate at least partially beneath the structure using a first etch process; forming a selective passivation layer on the substrate; and extending the recess in the substrate using a second etch process. The selective passivation layer is generally formed on regions of the substrate adjacent to the structure but generally not within the recess. The first and second etch processes may be the same or different.