Dry etching of TiN/Al(Cu)/Si for very large scale integrated local interconnections

Patterning Ti/TiN/Ti/Al(2 wt. % Cu)/Si interconnection lines over 700 nm topographic steps in Si02 with an angle of 84° is reported using a reactive ion etching. The etching gas is a mixture of BC13/C12/N2/CHC13 and the etching process uses a combination of high and low reactor pressures in a single wafer etching tool. No metal rails along the sidewall of topographic features were detected using an electrical test site. The etched metal profile shows a near vertical metal sidewall with negligible undercut. The metal linewidths are 0.7 to 1.8 μm wide with the variation of about 0.1 μm near the steps, due to resist linewidth variations over the topographic step. It also demonstrated that the Al(Cu) line can be a good landing pad for contact hole dielectric etching. © 1990, American Vacuum Society. All rights reserved.