Method for forming electrical contacts through multi-level dielectric layers by high density plasma etching

Abstract

A method for forming within a dielectric layer upon a substrate within a microelectronics fabrication a series of contact via holes etched through the dielectric layer to multi-level contact layers employing reactive plasma etching methods to form the series of contact via holes. The first plasma etch method employs fluorine containing gases to form the etched via holes, and then the second plasma etch method employs oxygen and a fluorocarbon gas to complete the etching of the via holes and remove residual materials. The etched via holes access multi-level contact layers formed upon the substrate at differing heights with respect to the substrate, penetrating through at least one contact layer. This permits formation of a series of electrical contacts, between the series of contact layers and patterned conductor layers through the series of via holes, with low electrical resistances.