CHARACTERIZATION OF PLASMA-ETCHED RUO_2 SUBSTRATES

摘要

New materials used as metal oxide conductors are being evaluated to maintain device performance or for specialized applications. The "noble metals" (platinum, palladium, osmium, indium, rhenium, and ruthenium) have desirable material properties in that they are thermally stable and resistant to oxidation and corrosion. However, because they are very hard materials, they can be difficult to etch. The use of ruthenium oxide has been proposed and demonstrated as a metal oxide gate electrode, but there are process and integration issues that must be addressed. In addition, there are health and safety issues with ruthenium oxide etch byproducts, including ruthenium tetroxide. This paper examines some aspects of etch performance of blanket ruthenium oxide as well as byproducts using a variety of gas-phase analytical techniques. In addition, the chemical environment and plasma conditions during which the toxic byproduct ruthenium tetroxide is formed are determined by gas-phase analytical techniques, as well as performance of the abatement device as a function of process conditions. Chamber cleans procedures are also described, both pre-maintenance plasma cleaning and wet cleans. Finally, surface analytical techniques are discussed in their application to ruthenium oxide, especially TXRF and TOF-SIMS.