Etch Stop Materials and Process for Reactive Ion Etching of Aluminum Copper
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
A set of material layers, reactive ion etch (RIE) gases and process sequence are described for RIE removal of aluminum-copper-silicon (AlCuSi) conductors while tolerating misalignment of etch masks over silicon (Si) or titanium disilicide (TiSi2) contacts. Thus, high line density need not be sacrificed by requiring fully-covered contacts. Referring to Fig. 1, a contact hole through insulator 2 is opened to contact diffusion 4 in Si substrate 6. A thin layer of titanium (Ti) 8 is deposited and heat treated to form TiSi2 9 where Ti contacts Si at the bottom of the contact hole opening. Next, a layer of tungsten (W) 10 is deposited followed by co-deposition of AlCuSi con ductive line material 12. Photoresist 14 is deposited and patterned for conductive line definition. In Fig.