Method for etching tungsten

摘要

A fluorine based metal etch chemistry, wherein an admixture of etch products (or species which are closely related to etch products) is added during the post etch stage, i.e. during the stage when the pattern has partially cleared by overetch is not yet completed, to maintain the balance of chemistries which provides selectivity and anisotropy. In a tungsten etch, WF6 is usefully added during the post etch period to provide this loading.