Reactive ion etching of metal stack consisting of an aluminium alloy, WGex, barrier and Ti adhesion layer

The increasing use of closely spaced narrow interconnections and generally reduced feature sizes in modern IC technology has led to a requirement for anisotropic etching of high performance metallizations. Etching processes addressing this requirement should exhibit good uniformity and reproducibility, a good selectivity over underlying materials and the mask to ensure a good pattern fidelity. WGe based barriers have good prospects in sub-micron contact barrier technology. The purpose of the present paper is to investigate the reactive ion etching (RIE) of blanket deposited AlCu/WGe/sub x//Ti films on SiO/sub 2/ in a chlorine based plasma chemistry employing a Cl/sub 2/, SiCl/sub 4/, He mixture. Various aspects of the metal stack etching including profile control, etch rate and selectivity to oxide are discussed in detail.