Self-aligned process

Abstract

Methods of forming self-aligned structures on patterned substrates are described. The methods may be used to form metal lines or vias without the use of a separate photolithography pattern definition operation. Self-aligned contacts may be produced regardless of the presence of spacer elements. The methods include directionally ion-implanting a gapfill portion of a gapfill silicon oxide layer to implant into the gapfill portion without substantially ion-implanting the remainder of the gapfill silicon oxide layer (the sidewalls). Subsequently, a remote plasma is formed using a fluorine-containing precursor to etch the patterned substrate such that the gapfill portions of silicon oxide are selectively etched relative to other exposed portions exposed parallel to the ion implantation direction. Without ion implantation, the etch operation would be isotropic owing to the remote nature of the plasma excitation during the etch process.