Fabrication processes for forming dual depth trenches using a dry etch that deposits a polymer

摘要

Trench isolation structures and methods to form same for use in the manufacture of semiconductor devices are described. The trench isolation structures are formed using several processing schemes that utilize disclosed dry etching processes to form a significant depth &Dgr; between an array trench depth and a periphery trench depth. One etching method creates a trench delta depth utilizing a single dry etch step, while two other etching methods create a trench &Dgr; depth by utilizing three dry etch steps.