High aspect ratio mask open without hardmask

摘要

A method of etching a stack of dielectric mask layers by reactive ion etch steps in order to open an aperture for etching into a semiconductor substrate improves the selectivity of the reactive ion etch relative to photoresist to the extent that an etch of an equivalent of 2000 nm of oxide is made with only photoresist as the etch mask, instead of a hardmask, thereby permitting the etch to be performed in a single chamber of an etch tool.