Patterning of 0.175 mu m platinum features using Ar/O-2 chemically assisted ion-beam etching

Argon/oxygen based chemically assisted ion-beam etching has been investigat ed for the patterning of stacked capacitor platinum electrodes at ground ru les of 200 nm and below. Titanium nitride and bilayers of titanium on top o f titanium nitride were used as hard mask layers in the patterning of the p latinum. The ion-beam platinum etch process relies on physical sputtering b y Ar ions with oxygen being added to the chamber during the etch to provide passivation of the Ti or TiN hard mask material. Pt:Ti etch selectivities of up to 20 have been achieved on blanket wafer samples. Sidewall profile a ngles greater than 80 degrees (measured from the horizontal) were obtained for tightly spaced platinum features with a pitch of 350 nm using a multipl e-angle ion-beam etch process. The uniformity of the etch process across 20 0 mm diam blanket oxide wafers was measured to be 3.5% (3 sigma value). (C) 2000 American Vacuum Society. [S0734-211X(00)03002-X].