Etch characteristics of an amorphous refractory absorber

An ECR etch process for defining sub-0.25 mu m features in a TaSiN absorber layer has been developed. A 2000 Angstrom PECVD oxide layer served as a hard mask during the etch. The effect on feature profile has been determined as a function of both rf power and back side temperature. Etch rate uniformity is excellent, with 3 sigma deviations of less than 4% over the center 40 mm of the substrate. Micro-loading issues associated with the etch process have also been characterized. Minimal line edge roughness is observed, and the feasibility for defining 0.10 mu m features has been demonstrated.