ADVANCED ETCHING TECHNIQUES FOR STRAIGHT TALL AND UNIFORM FINS ACROSS MULTIPLE FIN PITCH STRUCTURES

摘要

Embodiments of the present invention describe semiconductor devices having high aspect ratio fins and methods for forming such devices. According to one embodiment, a semiconductor device includes one or more nested fins and one or more isolated fins. According to one embodiment, a patterned hard mask comprising one or more isolated features and one or more nested features is formed using a hard mask etching process. A first substrate etch process forms isolated fins and nested fins in the substrate by transferring the pattern of nested features and isolated features of the hard mask to a first depth into the substrate. A second etch process is used to etch through the substrate to a second depth. According to embodiments of the present invention, the first etch process uses _{an etch chemistry comprising HBr, O 2} and CF ₄ , and the second etch process uses an etch chemistry comprising _{Cl 2} , Ar, and CH _{4 .} use the