A reactive ion etch study for producing patterned platinum structures

Abstract Various high-density DRAM and FRAM technologies currently under investigation utilize high-dielectric constant materials requiring noble metal or refractory metal oxide electrodes. In this paper we describe a study of platinum patterning by reactive ion etching (RIE). Platinum films were etched in a rf diode parallel plate RIE tool with a grounded upper electrode and a 13.56 rf powered lower electrode upon which substrates were processed. The removal characteristics of blanket platinum films and platinum films with a patterned photoresist etch mask were investigated as a function of gas chemistry (Ar, CF4, SF6, and Cl2), rf power (100 to 680 W), gas pressure (5 to 100 mTorr), total gas flow (5 to 80 scan), and substrate temperature (21 to 300°C). The platinum etch was characterized in terms of etch rate, amount of redeposited material observed on the photoresist etch sidewalls (‘fencing'), and etch scale-up non-uniformity versus small size and feature size. Platinum etch rates from 80 to 1250 A/m...