Silicon carbide deposition for use as a low-dielectric constant anti-reflective coating

Abstract

The present invention generally provides a process for depositing silicon carbide using a silane-based material with certain process parameters that is useful for forming a suitable ARC for IC applications. The same material may also be used as a barrier layer and an etch stop, even in complex damascene structures and with high diffusion conductors such as copper as a conductive material. Under certain process parameters, a fixed thickness of the silicon carbide may be used on a variety of thicknesses of underlying layers. The thickness of the silicon carbide ARC is substantially independent of the thickness of the underlying layer for a given reflectivity, in contrast to the typical need for adjustments in the ARC thickness for each underlying layer thickness to obtain a given reflectivity. A preferred process sequence for forming a silicon carbide anti-reflective coating on a substrate, comprises introducing silicon, carbon, and a noble gas into a reaction zone of a process chamber, initiating a plasma in the reaction zone, reacting the silicon and the carbon in the presence of the plasma to form silicon carbide, and depositing a silicon carbide anti-reflective coating on a substrate in the chamber. Another aspect of the invention includes a substrate having a silicon carbide anti-reflective coating, comprising a dielectric layer deposited on the substrate and a silicon carbide anti-reflective coating having a dielectric constant of less than about 7.0 and preferably about 6.0 or less.